<PAGE>

                                                                    EXHIBIT 2.37

                                AMENDMENT NO. 3
                         dated as of December 10, 2004

                                       to

                     AMENDED AND RESTATED CREDIT AGREEMENT
                         dated as of February 21, 2003

                                     among

                     FRESENIUS MEDICAL CARE HOLDINGS, INC.,
                            a New York corporation,
                           FRESENIUS MEDICAL CARE AG,
                             a German corporation,
                                      and
             the other Borrowers and Guarantors identified therein,

                        the Lenders identified therein,

                                      and

                             BANK OF AMERICA, N.A.,
                            as Administrative Agent

                        BANC OF AMERICA SECURITIES LLC,
                          CREDIT SUISSE FIRST BOSTON,
                   acting through its Cayman Islands Branch,
                                      and
                               DEUTSCHE BANK AG,
                 as Joint Lead Arrangers and Joint Book Runners
        for Increase to Revolving Commitments and Tranche A-1 Term Loan
<PAGE>

                                AMENDMENT NO. 3

     THIS AMENDMENT NO. 3, dated as of December 10, 2004 (this "Amendment"),
relating to the Credit Agreement (as defined below), by and among FRESENIUS
MEDICAL CARE AG ("FMCAG"), FRESENIUS MEDICAL CARE HOLDINGS, INC. ("FMCH"),
certain subsidiaries and affiliates of FMCAG party to the Credit Agreement (as
defined below) and identified on the signature pages hereto, and BANK OF
AMERICA, N.A., as Administrative Agent for and on behalf of the Lenders.
Capitalized terms used herein but not otherwise defined shall have the meanings
provided in the Credit Agreement (as defined below).

                              W I T N E S S E T H

     WHEREAS, a $1.5 billion credit facility was extended to FMCAG, FMCH and the
other Borrowers identified therein (collectively, the "Borrowers") pursuant to
the terms of that Amended and Restated Credit Agreement dated as of February 21,
2003 (as amended, modified and supplemented, the "Credit Agreement") among the
Borrowers, the Guarantors and Lenders identified therein, and the Administrative
Agent;

     WHEREAS, pursuant to the Tranche C Term Loan Joinder Agreement dated as of
August 22, 2003, the Tranche C Term Loan was made available to the Borrowers and
the proceeds of the Tranche C Term Loan (together with other sums) were
voluntarily applied by the Borrowers to prepay the Tranche B Term Loan in full;

     WHEREAS, pursuant to the Tranche D Term Loan Joinder Agreement dated as of
May 7, 2004, the Tranche D Term Loan was made available to the Borrowers and the
proceeds of the Tranche D Term Loan (together with other sums) were voluntarily
applied by the Borrowers to prepay the Tranche C Term Loan in full;

     WHEREAS, the Borrowers have requested certain modifications to the Credit
Agreement, including a request for an increase in the Aggregate Revolving
Committed Amount and to make available to the Borrowers a new Tranche A-1 term
loan, the proceeds of which, together with other sums and the proceeds of
Revolving Loans drawn on the Third Amendment Closing Date, will be applied as
voluntary prepayments on the existing Tranche A Term Loan and Tranche D Term
Loan;

     WHEREAS, the requisite Lenders pursuant to Section 11.01 of the Credit
Agreement have consented to the requested modifications on the terms and
conditions set forth herein and have authorized the Administrative Agent to
enter into this Amendment on their behalf;
<PAGE>

     NOW, THEREFORE, IN CONSIDERATION of these premises and other good and
valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, the parties hereto agree as follows:

     SECTION 1  Amendments to the Credit Agreement.  The Credit Agreement is
hereby amended and modified in the following respects:

          1.1  In Section 1.01 (Definitions) the following definitions are
     amended in their entirety or added to read as follows:

          "Applicable Percentage" means the following percentages per annum,
     based on the Consolidated Leverage Ratio as set forth in the most recent
     Compliance Certificate received by the Administrative Agent pursuant to
     Section 7.02(b):

<Table>
<Caption>
                                                             REVOLVING LOANS (INCLUDING L/C OBLIGATIONS)
                                                                      AND TRANCHE A-1 TERM LOAN
                                     TRANCHE A TERM LOAN    ---------------------------------------------
                                   -----------------------   EUROCURRENCY RATE
PRICING   CONSOLIDATED LEVERAGE    EUROCURRENCY  BASE RATE  LOANS AND LETTER OF   BASE RATE   COMMITMENT
 LEVEL            RATIO             RATE LOANS     LOANS         CREDIT FEE         LOANS         FEE
-------  ------------------------  ------------  ---------  --------------------  ----------  -----------
<S>      <C>                       <C>           <C>        <C>                   <C>         <C>
   I            > 3.5:1.0             2.25%        1.25%           1.25%            0.25%       0.30%
  II     > 3.0:1.0 but # 3.5:1.0      2.00%        1.00%           1.25%            0.25%       0.30%
  III    > 2.5:1.0 but # 3.0:1.0      1.75%        0.75%           1.00%             0%         0.30%
  IV     > 2.0:1.0 but # 2.5:1.0      1.50%        0.50%          0.875%             0%         0.25%
   V     > 1.5:1.0 but # 2.0:1.0      1.25%        0.25%           0.75%             0%         0.20%
  VI            # 1.5:1.0             1.25%        0.25%          0.625%             0%         0.15%
</Table>

     Any increase or decrease in the Applicable Percentage resulting from a
     change in the Consolidated Leverage Ratio shall become effective as of the
     date two Business Days immediately following the date a Compliance
     Certificate is delivered pursuant to Section 7.02(b); provided, however,
     that if a Compliance Certificate is not delivered when due in accordance
     therewith, then Pricing Level I shall apply as of the first Business Day
     after the date on which such Compliance Certificate was required to have
     been delivered until the first Business Day immediately following the date
     such Compliance Certificate is delivered; provided, further, that any
     decrease in the Applicable Percentage resulting from the Third Amendment
     shall take effect on the Third Amendment Closing Date.

          "Approved Jurisdiction" means Australia, Canada, France, Germany,
     Japan, Luxembourg, Switzerland, United Kingdom, Bermuda, any other
     Participating Member State as of the Closing Date, any jurisdiction of
     organization of a Domestic Subsidiary and any other jurisdiction approved
     by the Required Lenders.

          "Consolidated Fixed Charge Coverage Ratio" is deleted in its entirety.

          "Consolidated Net Interest Expense" means, for any period for the
     Consolidated Group, Consolidated Interest Expense minus interest income, as
     determined in accordance with GAAP.

          "Consolidated Interest Coverage Ratio" means, as of the end of each
     fiscal quarter for the period of four consecutive fiscal quarters then
     ending, the ratio of (i) Consolidated EBITDA to (ii) Consolidated Net
     Interest Expense.

          "Consolidated Net Income" means, for any period for the Consolidated
     Group, net income (or loss) determined on a consolidated basis in
     accordance with GAAP, but excluding for purposes of determining the
     Consolidated Leverage Ratio and the Consolidated Interest Coverage Ratio,
     extraordinary gains and losses and gains and losses from discontinued
     operations, and, in each such case, related tax effects thereon. Except as
     otherwise expressly provided, the applicable period shall be the four
     consecutive fiscal quarters ending as of the date of determination.

          "Interest Payment Date" means (a) as to any Base Rate Loan (other than
     a Swing Line Loan), the last Business Day of each March, June, September
     and December, the Termination Date and the dates of the final principal
     amortization installment on the Tranche A Term Loan, the Tranche A-1 Term
     Loan and the Tranche D Term Loan, as applicable, (b) as to any Swing Line
     Loan, the last Business Day of each March, June, September and December and
     the Termination Date, or such other days as may be

                                        2
<PAGE>

     mutually agreed upon by the Borrowers and the Swing Line Lender, and (c) as
     to any Eurocurrency Rate Loan or any Absolute Rate Loan, the last Business
     Day of each Interest Period for such Loan, the date of repayment of
     principal of such Loan, the Termination Date and the dates of the final
     principal amortization installment on the Tranche A Term Loan, the Tranche
     A-1 Term Loan and the Tranche D Term Loan, as applicable, and in addition,
     where the applicable Interest Period exceeds three months, the date every
     three months after the beginning of such Interest Period. If an Interest
     Payment Date falls on a date that is not a Business Day, such Interest
     Payment Date shall be deemed to be the next succeeding Business Day.

          "Lender Joinder Agreements" means any Revolving Loan Joinder
     Agreement, the Incremental Tranche A Term Loan Joinder Agreement, the
     Tranche A-1 Term Loan Joinder Agreement, the Tranche C Term Loan Joinder
     Agreement, and the Tranche D Term Loan Joinder Agreement.

          "Material Subsidiary" means (i) for FMCH, any Material Domestic
     Subsidiary and any Material Foreign Subsidiary of FMCH, and (ii) for FMCAG,
     (A) FMCH, (B) FMCD, (C) Fresenius Medical Care Beteiligungsgesellschaft
     mbH, (D) FMCF-II, (E) FMC Trust Finance S.a.r.l. Luxembourg, (F) FMC Trust
     Finance S.a.r.l. Luxembourg-III, (G) National Medical Care of Spain, S.A.,
     and (H) Fresenius Medical Care Japan K.K.

          "Outstanding Amount" means (a) with respect to Revolving Loans and
     Swing Line Loans on any date, the aggregate outstanding principal amount
     thereof after giving effect to any Borrowings and prepayments or repayments
     of Revolving Loans and Swing Line Loans, as the case may be, occurring on
     such date; (b) with respect to any L/C Obligations on any date, the amount
     of such L/C Obligations on such date after giving effect to any L/C Credit
     Extension occurring on such date and any other changes in the aggregate
     amount of the L/C Obligations as of such date, including as a result of any
     reimbursements of outstanding unpaid drawings under any Letters of Credit
     or any reductions in the maximum amount available for drawing under Letters
     of Credit taking effect on such date; (c) with respect to the Tranche A
     Term Loan on any date, the aggregate outstanding principal amount thereof
     after giving effect to any prepayments or repayments of the Tranche A Term
     Loan on such date; (d) with respect to the Tranche A-1 Term Loan on any
     date, the aggregate outstanding principal amount thereof after giving
     effect to any prepayments or repayments of the Tranche A-1 Term Loan on
     such date; and (e) with respect to the Tranche D Term Loan on any date, the
     aggregate outstanding principal amount thereof after giving effect to any
     prepayments or repayments of the Tranche D Term Loan on such date.

          "Required Tranche A-1 Term Lenders" means, as of any date of
     determination, Lenders holding in the aggregate more than 50% of the
     Tranche A-1 Term Loan; provided that the portion of the Tranche A-1 Term
     Loan held, or deemed held by, any Defaulting Lender shall be excluded for
     purposes of making a determination of Required Tranche A-1 Term Lenders.

          "Revolving Loan Joinder Agreements" means, collectively, the Revolving
     Loan Joinder Agreement entered into on the Second Amendment Closing Date
     and any Revolving Loan Joinder Agreement substantially in the form of
     Exhibit K, including any that are entered into in connection with the
     increase of the Revolving Commitments pursuant to Section 2.01(j).

          "Term Loan" means the Tranche A Term Loan, the Tranche A-1 Term Loan,
     the Tranche B Term Loan, the Tranche C Term Loan and the Tranche D Term
     Loan.

          "Term Loan Commitments" means the Tranche A Term Loan Commitment, the
     Tranche A-1 Term Loan Commitment, the Tranche B Term Loan Commitment, the
     Tranche C Term Loan Commitment and the Tranche D Term Loan Commitment.

          "Term Notes" means the Tranche A Term Notes, the Tranche A-1 Term
     Notes, the Tranche B Term Notes, the Tranche C Term Notes and the Tranche D
     Term Notes.

          "Termination Date" means February 28, 2010.

                                        3
<PAGE>

          "Third Amendment" means that certain Amendment No. 3 dated as of
     December 10, 2004, relating to the Credit Agreement, by and among FMCAG,
     FMCH, certain subsidiaries and affiliates of FMCAG, and the Administrative
     Agent for and on behalf of the Lenders.

          "Third Amendment Closing Date" means December 10, 2004.

          "Tranche A-1 Term Lenders" means, prior to funding of the Tranche A-1
     Term Loan, Lenders with Tranche A-1 Term Loan Commitments, and after
     funding of the Tranche A-1 Term Loan, Lenders holding a portion of the
     Tranche A-1 Term Loan, together with their successors and permitted
     assigns.

          "Tranche A-1 Term Loan" shall have the meaning provided in Section
     2.01(f-1).

          "Tranche A-1 Term Loan Commitment" means the commitment of each
     Tranche A-1 Term Lender to make its portion of the Tranche A-1 Term Loan
     hereunder as set forth in the Tranche A-1 Term Loan Joinder Agreement.

          "Tranche A-1 Term Loan Commitment Percentage" means, for each Tranche
     A-1 Term Lender, a fraction (expressed as a percentage carried to the ninth
     decimal place), the numerator of which is, prior to funding of the Tranche
     A-1 Term Loan, such Tranche A-1 Term Lender's Tranche A-1 Term Loan
     Committed Amount, and, after funding of the Tranche A-1 Term Loan, the
     principal amount of such Tranche A-1 Term Lender's Tranche A-1 Term Loan
     and the denominator of which is, prior to funding of the Tranche A-1 Term
     Loan, the aggregate principal amount of the Tranche A-1 Term Loan Committed
     Amounts, and, after funding of the Tranche A-1 Term Loan, the aggregate
     principal amount of the Tranche A-1 Term Loan. The initial Tranche A-1 Term
     Loan Commitment Percentages are shown on Schedule 2.01.

          "Tranche A-1 Term Loan Committed Amount" means, with respect to each
     Tranche A-1 Term Lender, the amount of such Lender's Tranche A-1 Term Loan
     Commitment. The initial Tranche A-1 Term Loan Committed Amounts will be as
     set forth in the Tranche A-1 Term Loan Joinder Agreement.

          "Tranche A-1 Term Loan Joinder Agreement" means the Tranche A-1 Term
     Loan Joinder Agreement, if any, providing for the establishment of the
     Tranche A-1 Term Loan, substantially in the form of Exhibit L.

          "Tranche A-1 Term Note" means the promissory notes given to each
     Tranche A-1 Term Lender to evidence the Tranche A-1 Term Loan, as amended,
     restated, modified, supplemented, extended, renewed or replaced. A form of
     Tranche A-1 Term Note is attached as Exhibit C-6.

     1.2  In Section 2.01(a), clause (ii)(A) is amended to read as follows:

          "(A) the aggregate principal amount of Revolving Obligations shall not
     exceed SEVEN HUNDRED FIFTY MILLION DOLLARS ($750,000,000) (as such amount
     may be increased or decreased in accordance with the provisions hereof, the
     "Aggregate Revolving Committed Amount") and"

     1.3  In Section 2.01, a new subsection (f-1) is added immediately following
subsection (f) and immediately before subsection (g) to read as follows:

          "(f-1) Tranche A-1 Term Loan Commitment. On the Third Amendment
     Closing Date, each of the Tranche A-1 Term Lenders severally agrees to make
     its portion of a term loan (in the amount of its respective Tranche A-1
     Term Loan Committed Amount) in a single advance in Dollars to FMCH and
     FMCAG, as co-borrowers, in an aggregate principal amount of FOUR HUNDRED
     FIFTY MILLION DOLLARS ($450,000,000) (the "Tranche A-1 Term Loan"). The
     Tranche A-1 Term Loan may consist of Base Rate Loans, Eurocurrency Rate
     Loans or a combination thereof, as such Borrower may request. Amounts
     repaid on the Tranche A-1 Term Loan may not be reborrowed."

     1.4  In Section 2.01(j) (Increase in Revolving Commitments), the lead-in
sentence is amended to read as follows:

          "On or after the Third Amendment Closing Date, FMCH and FMCAG may,
     from time to time, upon written notice to the Administrative Agent,
     increase the Aggregate Revolving Committed Amount

                                        4
<PAGE>

     by up to TWO HUNDRED MILLION DOLLARS ($200,000,000) to not more than NINE
     HUNDRED FIFTY MILLION DOLLARS ($950,000,000); provided that:"

     1.5  In Section 2.02 (Borrowings, Conversions and Continuations of Loans),
subsection (e) is amended to read as follows:

          "(e) After giving effect to all Borrowings, all conversions of Loans
     from one Type to the other, and all continuations of Loans as the same
     Type, (i) there shall not be more than twenty Interest Periods in effect
     with respect to all Committed Revolving Loans hereunder, (ii) there shall
     not be more than five Interest Periods in effect with respect to the
     Tranche A Term Loan, (iii) there shall not be more than five Interest
     Periods in effect with respect to the Tranche A-1 Term Loan, and (iv) there
     shall not be more than five Interest Periods in effect with respect to the
     Tranche D Term Loan; provided in each case that, for purposes hereof,
     Interest Periods with respect to Loans (whether or not of the same Type)
     with separate or different Interest Periods will be considered as separate
     Interest Periods, even if such Interest Periods end on the same date."

     1.6  In Section 2.05 (Repayment of Loans), a new subsection (d-1) is added
immediately following subsection (d) and immediately before subsection (e) to
read as follows:

          (d-1) Tranche A-1 Term Loan. The Borrower shall repay to the Lenders
     the principal amount of the Tranche A-1 Term Loan in quarterly installments
     on the dates set forth below, commencing on December 31, 2005, as follows:

<Table>
<Caption>
                                                              PRINCIPAL
DATE                                                    AMORTIZATION PAYMENT
----                                                    ---------------------
<S>                                                     <C>
December 31, 2005.....................................         $25,000,000.00
March 31, 2006........................................         $25,000,000.00
June 30, 2006.........................................         $25,000,000.00
September 30, 2006....................................         $25,000,000.00
December 31, 2006.....................................         $25,000,000.00
March 31, 2007........................................         $25,000,000.00
June 30, 2007.........................................         $25,000,000.00
September 30, 2007....................................         $25,000,000.00
December 31, 2007.....................................         $25,000,000.00
March 31, 2008........................................         $25,000,000.00
June 30, 2008.........................................         $25,000,000.00
September 30, 2008....................................         $25,000,000.00
December 31, 2008.....................................         $25,000,000.00
March 31, 2009........................................         $25,000,000.00
June 30, 2009.........................................         $25,000,000.00
September 30, 2009....................................         $25,000,000.00
December 31, 2009.....................................         $25,000,000.00
February 28, 2010.....................................  Outstanding Amount of
                                                        Tranche A-1 Term Loan
                                                        ---------------------
Total.................................................        $450,000,000.00
                                                        =====================
</Table>

     1.7  Section 2.06(c)(i) (Application of Voluntary Prepayments) is replaced
in its entirety to read as follows:

          "(i) Voluntary Prepayments. Voluntary prepayments shall be applied as
     specified by the Borrowers; provided that (A) any voluntary prepayment on
     the Term Loans shall be applied first to payment of the Tranche D Term Loan
     until paid in full, then to payment of the Tranche A Term Loan until paid
     in full and then to payment of the Tranche A-1 Term Loan, (B) voluntary
     prepayments on the Tranche A Term

                                        5
<PAGE>

     Loan shall be applied pro rata to remaining principal amortization
     installments thereunder, (C) voluntary prepayments on the Tranche A-1 Term
     Loan shall be applied pro rata to remaining principal amortization
     installments thereunder, and (D) prepayments on the Tranche D Term Loan
     shall be applied to remaining principal amortization installments in
     inverse order of maturity. Voluntary prepayments on the Loan Obligations
     will be paid by the Administrative Agent to the Lenders ratably in
     accordance with their respective interests therein."

     1.8  In Section 2.06(c)(ii) (Application of Mandatory Prepayments),
subsection (B) is amended to read as follows:

          "(B) Mandatory prepayments in respect of Dispositions under subsection
     (b)(ii) above, Debt Transactions under subsection (b)(iii) and
     Securitization Transactions under subsection (b)(iv) above shall be applied
     first to the Term Loans until paid in full, and then to the Revolving
     Obligations. Mandatory prepayments on the Term Loans shall be applied first
     to payment of the Tranche D Term Loan until paid in full, then to payment
     of the Tranche A Term Loan until paid in full and then to payment of the
     Tranche A-1 Term Loan. Prepayments on the Tranche A Term Loan and the
     Tranche A-1 Term Loan shall be applied pro rata to remaining principal
     amortization installments thereunder and prepayments on the Tranche D Term
     Loan shall be applied to remaining principal amortization installments in
     inverse order of maturity."

     1.9  In Section 2.13 (Evidence of Debt), in subsection (a) the next-to-last
sentence is amended to read as follows:

          "The Borrowers shall execute and deliver to the Administrative Agent
     (i) a Revolving Note for each Revolving Lender that so requests, (ii) a
     Tranche A Term Note for each Tranche A Term Lender that so requests, (iii)
     a Tranche A-1 Term Note for each Tranche A-1 Term Lender that so requests,
     (iv) a Tranche B Term Note for each Tranche B Term Lender that so requests,
     (v) a Tranche C Term Note for each Tranche C Term Lender that so requests
     and (vi) a Tranche D Term Note for each Tranche D Term Lender that so
     requests, which Notes, in addition to such accounts or records, shall
     evidence such Lender's Loans."

     1.10  In Section 2.14 (Payments Generally), the next-to-last sentence in
subsection (a) is amended to add a new clause "(ii-A)" immediately after clause
(ii) and immediately before clause (iii) to read as follows:

          "(ii-A) with respect to such payments on the Tranche A-1 Term Loan,
     its Tranche A-1 Term Loan Commitment Percentage thereof, and"

     1.11  A new paragraph is added at the end of Section 7.02 (Certificates;
Other Information), to read as follows:

          The Borrowers hereby acknowledge that (A) the Administrative Agent
     will make available to the Lenders materials and/or information provided by
     or on behalf of the Borrowers hereunder (collectively, the "Borrower
     Materials") by posting the Borrower Materials on IntraLinks or another
     similar electronic system (the "Platform") and (B) certain of the Lenders
     may be "public-side" Lenders (i.e., Lenders that do not wish to receive
     material non-public information with respect to the Borrowers or their
     securities) (each, a "Public Lender"). The Borrowers hereby further agree
     that (1) all Borrower Materials that are to be made available to Public
     Lenders shall be clearly and conspicuously marked "PUBLIC" which, at a
     minimum, shall mean that the word "PUBLIC" shall appear prominently on the
     first page thereof; (2) by marking Borrower Materials "PUBLIC," the
     Borrowers shall be deemed to have authorized the Administrative Agent and
     the Lenders to treat such Borrower Materials as either publicly available
     information or not material information (although it may be sensitive and
     proprietary) with respect to the Borrowers or their securities for purposes
     of United States federal and state securities laws; (3) all Borrower
     Materials marked "PUBLIC" are permitted to be made available through a
     portion of the Platform designated as "Public Investor"; and (4) the
     Administrative Agent shall be entitled to treat and shall treat any
     Borrower Materials that are not marked "PUBLIC" as being suitable only for
     posting on a portion of the Platform not marked as "Public Investor".

                                        6
<PAGE>

     1.12  In Section 7.13 (Pledge of Capital Stock) the parenthetical reference
"(whether currently existing or hereafter formed or acquired)" appearing at the
end of subsection (b) just before the proviso is deleted.

     1.13  In Section 8.01 (Indebtedness), clause (i) of the proviso in
subsection (j) is amended to read as follows:

          (i) the maturity date for any such debt is not earlier than the final
     maturity date of the Tranche A-1 Term Loan,

     1.14  Section 8.07 (Prepayment of Other Subordinated Debt) is deleted in
its entirety.

     1.15  In Section 8.13 (Financial Covenants), subsections (a) and (b) are
amended to read as follows:

          (a) Consolidated Leverage Ratio. As of the end of each fiscal quarter,
     the Consolidated Leverage Ratio will not exceed:

<Table>
<Caption>
                                                                 MAXIMUM
                                                               CONSOLIDATED
FISCAL QUARTER ENDING                                         LEVERAGE RATIO
---------------------                                         --------------
<S>                                                           <C>
Prior to December 30, 2004..................................     3.50:1.0
December 31, 2004 through December 30, 2005.................     3.25:1.0
December 31, 2005 through December 30, 2006.................      3.0:1.0
December 31, 2006 through December 30, 2007.................     2.75:1.0
December 31, 2007 and thereafter............................     2.50:1.0
</Table>

          (b) Consolidated Interest Coverage Ratio. As of the end of each fiscal
     quarter, the Consolidated Interest Coverage Ratio will not be less than
     4.5:1.0.

     1.16  In Section 11.01 (Amendments), a new subsection "(c-1)" is added
immediately following subsection (c) and immediately before subsection (d) to
read as follows:

          "(c-1) unless also signed by the Required Tranche A-1 Term Lenders, no
     such amendment, waiver or consent shall:

             (i) amend or waive any mandatory prepayment on the Tranche A-1 Term
        Loan Obligations under Section 2.06(b) or the manner of application
        thereof to the Tranche A-1 Term Loan Obligations under Section 2.06(c),
        or

             (ii) amend or waive the provisions of this Section 11.01(c-1) or
        the definition of "Required Tranche A-1 Term Lenders";"

     1.17  In Section 11.16 (Replacement of Lenders) the lead-in clause
immediately preceding the phrase "the Borrower may, upon notice to such Lender
and the Administrative Agent" shall be amended to read as follows:

          "Under any circumstance set forth herein providing that the Borrowers
     shall have the right to replace a Lender as a party to this Agreement and
     also under any circumstance where a Lender shall refuse to consent to a
     proposed amendment, waiver or consent hereunder that has been approved by
     the Required Lenders, the Required Revolving Lenders, the Required Tranche
     A Term Lenders, or the Required Tranche A-1 Term Lenders, as appropriate,
     (including, without limitation by a failure to respond in writing to a
     proposed amendment by the date and time specified by the Administrative
     Agent),"

     1.18  Section 11.21 (Reallocation of Commitments) is replaced in its
entirety to read as follows:

          11.21  Reallocation of Commitments.  Each Revolving Lender that will
     hold a greater percentage of the Revolving Commitments on the Third
     Amendment Closing Date than such Lender held immediately prior to such
     Third Amendment Closing Date, including any New Lender (as defined in the
     Revolving Loan Joinder Agreement entered into on or about such Third
     Amendment Closing Date) (each, a "Purchasing Lenders" and, collectively,
     the "Purchasing Lenders") shall be deemed to have

                                        7
<PAGE>

     automatically purchased an assignment and assumption on a pro rata basis
     from each Revolving Lender that will hold a lesser percentage of the
     Revolving Commitments on the Third Amendment Closing Date that such
     Revolving Lender held prior to the effectiveness thereof (including,
     without limitation, any Lender being replaced pursuant to Section 11.16)
     (the "Selling Lenders"), effective as of the Third Amendment Closing Date
     simultaneously with the effectiveness thereof and the voluntary repayment
     of the Tranche A Loans contemplated thereby, of all of such Selling
     Lender's rights and obligations (including, to the extent permitted to be
     assigned under applicable law, all claims, suits, causes of action and any
     other right of such Selling Lender against any Person, whether known or
     unknown, arising under or in connection with the Credit Agreement, the
     documents delivered pursuant thereto and the transactions governed thereby
     or in any way based on or related to any of the foregoing, whether at law
     or in equity) under the Credit Agreement and the other Credit Documents to
     the extent related to such Selling Lender's Assigned Interest (as defined
     below) such that, after giving effect to such assignment and assumptions,
     each Lender's Commitments shall be as set forth on Schedule 2.01 or in the
     case of Lenders being replaced under Section 11.16, shall be terminated as
     of the Third Amendment Closing Date. Each such assignment and assumption
     shall be at par and without recourse, representation or warranty, provided
     that each Selling Lender shall be deemed to represent and warrant to each
     Purchasing Lender that it is the legal and beneficial owner of its Assigned
     Interest and that the rights and obligations assigned by such Selling
     Lender are free and clear of any lien, encumbrance or other adverse claim
     created by such Selling Lender. For purposes of this provision, "Assigned
     Interest" means with respect to any Selling Lender, the remainder of (a)
     the amount and percentage interest of such Selling Lender under the Credit
     Agreement as in effect immediately prior to the effectiveness of the Third
     Amendment less (b) the amount and percentage interest of the rights and
     obligations of such Selling Lender immediately following the effectiveness
     of the Third Amendment.

     1.19  The portion of Schedule 2.01 (Commitments and Commitment Percentages)
relating to the Revolving Commitments and the Tranche A-1 Term Loan will be
amended as of the Third Amendment Date, to set forth the Revolving Committed
Amounts and the Tranche A-1 Term Loan Committed Amounts, and the Revolving
Commitment Percentages and the Tranche A-1 Term Loan Commitment Percentages,
respectively, in effect immediately after the effectiveness hereof.

     1.20  Exhibit A-1 (Form of Loan Notice) is replaced in its entirety with
Exhibit A-1 attached hereto.

     1.21  A new Exhibit C-6 (Form of Tranche A-1 Term Note) is added in the
form of Exhibit C-6 attached hereto.

     1.22  Exhibit K (Form of Revolving Loan Joinder Agreement) is replaced in
its entirety with Exhibit K attached hereto.

     SECTION 2  Consent.

     2.1  Consent is hereby given to waive the voluntary prepayment notice
provisions of Section 2.06(a)(i) with respect to the voluntary prepayment in
full by the Borrowers to be made to the Tranche A Term Loan and the Tranche D
Term Loan on the Third Amendment Closing Date.

     SECTION 3  Conditions Precedent.  The effectiveness of this Amendment is
subject to receipt by the Administrative Agent of the following, each in form
and substance satisfactory to the Administrative Agent:

          (a) copies of this Amendment executed by each of the Borrowers and the
     Guarantors;

          (b) the consent of the Required Lenders;

          (c) the consent of the Revolving Lenders;

          (d) the consent of the Required Tranche A Term Lenders;

          (e) the consent of the Tranche A-1 Term Lenders;

          (f) to the extent reasonably necessary in the judgment of the
     Administrative Agent, amendments to each foreign Pledge Agreement and the
     Parallel Debt Agreement and/or delivery of any substantially

                                        8
<PAGE>

     similar agreement that creates an obligation of the Credit Parties (as debt
     acknowledgment or abstraktes Schuldanerkenntnis), in each case in a manner
     satisfactory to the Administrative Agent;

          (g) opinions of counsel to the Borrowers and the Guarantors; and

          (h) payment of the reasonable fees and expenses of counsel to the
     Administrative Agent (including Moore & Van Allen, PLLC and foreign
     counsel) relating to the Credit Agreement and this Amendment;

provided that the effectiveness of the amendments to Sections 11.16 and 11.21 of
the Credit Agreement contemplated by Section 1.17 and Section 1.18 hereby shall
become effective upon the satisfaction of the conditions set forth in (a) and
(b).

     SECTION 4  Miscellaneous.

     4.1  Except as modified hereby, all of the terms and provisions of the
Credit Agreement (including Schedules and Exhibits) remain in full force and
effect.

     4.2  The Credit Parties hereby affirm (a) the representations and
warranties set forth in Article VI of the Credit Agreement are true and correct
in all material respects as of the date hereof (except those which expressly
relate to an earlier period) and (b) no Default or Event of Default exists as of
the date hereof.

     4.3  The Credit Parties hereby affirm the liens and security interests
created and granted in the Credit Documents and agree that this Amendment is not
intended to adversely affect or impair such liens and security interests in any
manner.

     4.4  Each Guarantor (a) acknowledges and consents to all of the terms and
conditions of this Amendment, (b) affirms such Guarantor's obligations under the
Credit Documents and (c) agrees that this Amendment does not operate to reduce
or discharge such Guarantor's obligations under the Credit Documents.

     4.5  FMCAG agrees to pay all reasonable fees and expenses of the
Administrative Agent in connection with the preparation, execution and delivery
of this Amendment, including without limitation the reasonable fees and expenses
of Moore & Van Allen, PLLC and of foreign counsel to the Administrative Agent.

     4.6  This Amendment may be executed in any number of counterparts, each of
which when so executed and delivered shall be deemed an original and it shall
not be necessary in making proof of this Amendment to produce or account for
more than one such counterpart. Delivery by any party hereto of an executed
counterpart of this Amendment by facsimile shall be effective as such party's
original executed counterpart and shall constitute a representation that such
party's original executed counterpart will be delivered promptly.

     4.7  THIS AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED AND INTERPRETED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK APPLICABLE TO AGREEMENTS MADE
AND TO BE PERFORMED ENTIRELY WITHIN SUCH STATE.

                  [remainder of page intentionally left blank]

                                        9
<PAGE>

     IN WITNESS WHEREOF, each of the parties hereto has caused a counterpart of
this Amendment to be duly executed and delivered as of the date first above
written.

<Table>
<S>                                            <C>
BORROWERS AND GUARANTORS:                      FRESENIUS MEDICAL CARE AG, a German
                                               corporation, as a Borrower and as a Guarantor
</Table>

                                          By:      /s/ Lawrence A. Rosen
                                            ------------------------------------
                                            Name:     Lawrence A. Rosen
                                              Title:   Chief Financial Officer/
                                                Member of the Management Board

                                          By:       /s/ Dr. Rainer Runte
                                            ------------------------------------
                                            Name:     Dr. Rainer Runte
                                            Title:   Member of the Management
                                                     Board

                                          FRESENIUS MEDICAL CARE HOLDINGS, INC.,
                                          a New York corporation, as a Borrower
                                          and as a Guarantor

                                          By:         /s/ Mark Fawcett
                                            ------------------------------------
                                            Name:     Mark Fawcett
                                            Title:   Assistant Treasurer

                                          FMC FINANCE II S.a.r.l., a private
                                          limited company (societe a
                                          responsabilite limitee) organized
                                          under the laws of Luxembourg, as a
                                          Borrower and as a Guarantor

                                          By:         /s/ Gabriele Dux
                                            ------------------------------------
                                            Name:     Gabriele Dux
                                            Title:   Managing Director

                                          By:        /s/ Andrea Stopper
                                            ------------------------------------
                                            Name:     Andrea Stopper
                                            Title:   Managing Director
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    NATIONAL MEDICAL CARE, INC., a Delaware
                                               corporation
</Table>

                                          By:         /s/ Mark Fawcett
                                            ------------------------------------
                                            Name:     Mark Fawcett
                                            Title:   Treasurer

                                          FRESENIUS MEDICAL CARE DEUTSCHLAND
                                          GmbH, a German corporation

                                          By:        /s/ Emanuele Gatti
                                            ------------------------------------
                                            Name:     Dr. Emanuele Gatti
                                            Title:   Managing Director

                                          By:        /s/ Norbert Weber
                                            ------------------------------------
                                            Name:     Norbert Weber
                                            Title:   Managing Director

                                          FMC TRUST FINANCE S.a.r.l. LUXEMBOURG,
                                          a private limited company (societe a
                                          responsabilite limitee) organized
                                          under the laws of Luxembourg

                                          By:        /s/ Andrea Stopper
                                            ------------------------------------
                                            Name:     Andrea Stopper
                                            Title:   Managing Director

                                          FMC TRUST FINANCE S.a.r.l.
                                          LUXEMBOURG-III, a private limited
                                          company (societe a responsabilite
                                          limitee) organized under the laws of
                                          Luxembourg

                                          By:         /s/ Gabriele Dux
                                            ------------------------------------
                                            Name:     Gabriele Dux
                                            Title:   Managing Director
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    BIO-MEDICAL APPLICATIONS MANAGEMENT COMPANY,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF ARIZONA, INC., a
                                               Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF CALIFORNIA, INC.,
                                               a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF LOUISIANA, LLC, a
                                               Delaware limited liability company,
                                               BIO-MEDICAL APPLICATIONS OF MAINE, INC., a
                                               Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF
                                               NEW MEXICO, INC., a Delaware corporation,
                                               FMS NEW YORK, INC., a Delaware corporation
                                               formerly known as Bio-Medical Applications of
                                               New York, Inc.
                                               BIO-MEDICAL APPLICATIONS OF NORTH CAROLINA,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF PENNSYLVANIA,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF SOUTH CAROLINA,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF TEXAS, INC., a
                                               Delaware corporation,
                                               EVEREST HEALTHCARE HOLDINGS, INC., a Delaware
                                               corporation,
                                               FRESENIUS USA MANUFACTURING, INC., a Delaware
                                               corporation,
                                               FRESENIUS USA MARKETING, INC., a Delaware
                                               corporation,
                                               FRESENIUS USA, INC., a Massachusetts
                                               corporation,
                                               SPECTRA LABORATORIES, INC., a Nevada
                                               corporation
</Table>

                                          By:         /s/ Mark Fawcett
                                            ------------------------------------
                                            Name:     Mark Fawcett
                                              Title:   Treasurer
                                                 for each of the foregoing
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    NMC A, LLC, a Delaware limited liability
                                               company
</Table>

                                          By:         /s/ Mark Fawcett
                                            ------------------------------------
                                            Name:     Mark Fawcett
                                            Title:   Treasurer

                                          FRESENIUS MEDICAL CARE US
                                          BETEILIGUNGSGESELLSCHAFT mbH, a German
                                          limited liability company

                                          By:      /s/ Lawrence A. Rosen
                                            ------------------------------------
                                            Name:     Lawrence A. Rosen
                                            Title:   Managing Director

                                          By:         /s/ Josef Dinger
                                            ------------------------------------
                                            Name:     Josef Dinger
                                            Title:   Managing Director

                                          FRESENIUS MEDICAL CARE
                                          BETEILIGUNGSGESELLSCHAFT mbH, a German
                                          limited liability company

                                          By:      /s/ Lawrence A. Rosen
                                            ------------------------------------
                                            Name:     Lawrence A. Rosen
                                            Title:   Managing Director

                                          By:       /s/ Dr. Rainer Runte
                                            ------------------------------------
                                            Name:     Dr. Rainer Runte
                                            Title:   Managing Director
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    FRESENIUS MEDICAL CARE US ZWEI
                                               BETEILIGUNGSGESELLSCHAFT mbH, a German limited
                                               liability company, formerly known as Gabriele
                                               41 Vermogensverwaltung GmbH
</Table>

                                          By:      /s/ Lawrence A. Rosen
                                            ------------------------------------
                                            Name:     Lawrence A. Rosen
                                            Title:   Managing Director

                                          By:         /s/ Josef Dinger
                                            ------------------------------------
                                            Name:     Josef Dinger
                                            Title:   Managing Director

                                          FRESENIUS MEDICAL CARE US DREI
                                          BETEILIGUNGSGESELLSCHAFT mbH, a German
                                          limited liability company

                                          By:      /s/ Lawrence A. Rosen
                                            ------------------------------------
                                            Name:     Lawrence A. Rosen
                                            Title:   Managing Director

                                          By:         /s/ Josef Dinger
                                            ------------------------------------
                                            Name:     Josef Dinger
                                            Title:   Managing Director

<Table>
<S>                                            <C>
ADMINISTRATIVE AGENT:                          BANK OF AMERICA, N.A., as Administrative Agent
                                               for and on behalf of the Lenders
</Table>

                                          By:       /s/ Cassandra McCain
                                            ------------------------------------
                                            Name:     Cassandra McCain
                                            Title:   Officer
<PAGE>

                                 Schedule 2.01
                            Schedule of Commitments
                     as of the Third Amendment Closing Date

<Table>
<Caption>
                                                                                                          TRANCHE A
                                                                       REVOLVING                          TERM LOAN
                                                      REVOLVING        COMMITMENT       TRANCHE A-1      COMMITMENT
LENDER                                               COMMITMENT        PERCENTAGE        TERM LOAN       PERCENTAGE
------                                             ---------------   --------------   ---------------   -------------
<S>                                                <C>               <C>              <C>               <C>
BANK OF AMERICA..................................  $ 28,125,000.00     3.7500000000%  $    16,875,000      3.75000000%
CREDIT SUISSE FIRST BOSTON.......................    28,125,000.00     3.7500000000%       16,875,000      3.75000000%
DEUTSCHE BANK LUXEMBOURG SA......................    28,125,000.00     3.7500000000%       16,875,000      3.75000000%
BANK OF NOVA SCOTIA..............................    26,250,000.00     3.5000000000%       15,750,000      3.50000000%
JPMORGAN CHASE BANK..............................    26,250,000.00     3.5000000000%       15,750,000      3.50000000%
ABN-AMRO BANK N.V. NIEDERLASSUNG DEUTSCHLAND.....    25,625,000.00     3.4166666667%       15,375,000      3.41666667%
COMMERZBANK AKTIENGESELLSCHAFT...................    25,625,000.00     3.4166666667%       15,375,000      3.41666667%
DRESDNER BANK AKTIENGESELLSCHAFT.................    25,625,000.00     3.4166666667%       15,375,000      3.41666667%
DZ BANK AG.......................................    25,625,000.00     3.4166666667%       15,375,000      3.41666667%
KREDITANSTALT FUR WIEDERAUFBAU...................    25,625,000.00     3.4166666667%       15,375,000      3.41666667%
MIZUHO CORPORATE BANK GERMANY....................    25,625,000.00     3.4166666667%       15,375,000      3.41666667%
SOCIETE GENERALE.................................    25,625,000.00     3.4166666667%       15,375,000      3.41666667%
LANDESBANK HESSEN-THUERINGEN.....................   25,625,000.000     3.4166666667%       15,375,000      3.41666667%
BANK AUSTRIA CREDITANSTALT.......................    12,187,500.00     1.6250000000%        7,312,500      1.62500000%
BAYERISCHE HYPO- UND VEREINSBANK AG New York
  Branch.........................................    12,187,500.00     1.6250000000%        7,312,500      1.62500000%
BNP PARIBAS......................................    24,375,000.00     3.2500000000%       14,625,000      3.25000000%
SUNTRUST BANK....................................    24,375,000.00     3.2500000000%       14,625,000      3.25000000%
WACHOVIA BANK NATIONAL ASSOCIATION...............    24,375,000.00     3.2500000000%       14,625,000      3.25000000%
WEST LB AG, New York Branch......................    24,375,000.00     3.2500000000%       14,625,000      3.25000000%
BARCLAYS BANK PLC................................    22,500,000.00     3.0000000000%       13,500,000      3.00000000%
BAYERISCHE LANDESBANK............................    22,500,000.00     3.0000000000%       13,500,000      3.00000000%
UFJ BANK, LTD. ..................................    22,500,000.00     3.0000000000%       13,500,000      3.00000000%
SUMITOMO MITSUI BANKING CORPORATION, DUESSELDORF
  BRANCH.........................................    22,500,000.00     3.0000000000%       13,500,000      3.00000000%
BANCO BILBAO VIZCAYA ARGENTARIA S.A. ............    19,375,000.00     2.5833333333%       11,625,000      2.58333333%
BANK OF NEW YORK.................................    19,375,000.00     2.5833333333%       11,625,000      2.58333333%
BANK OF TOKYO-MITSUBISHI TRUST CO................    19,375,000.00     2.5833333333%       11,625,000      2.58333333%
ING BHF BANK AKTIENGESELLSCHAFT..................    19,375,000.00     2.5833333333%       11,625,000      2.58333333%
RAIFFEISEN ZENTRALBANK OSTERREICH................   13,839,285.714     1.8452380952%     8,303,571.43      1.84523810%
RZB FINANCE LLC..................................    5,535,714.286     0.7380952381%     3,321,428.57      0.73809524%
ALLIED IRISH BANK PLC............................    15,000,000.00     2.0000000000%        9,000,000      2.00000000%
THE GOVERNOR AND CO OF THE BANK OF IRELAND.......    15,000,000.00     2.0000000000%        9,000,000      2.00000000%
KEYBANK NA.......................................    15,000,000.00     2.0000000000%        9,000,000      2.00000000%
LANDESBANK SACHSEN GIROZENTRALE..................    15,000,000.00     2.0000000000%        9,000,000      2.00000000%
NATEXIS BANQUES POPULAIRES.......................    15,000,000.00     2.0000000000%        9,000,000      2.00000000%
NATIONAL CITY BANK OF KENTUCKY...................    15,000,000.00     2.0000000000%        9,000,000      2.00000000%
DEUTSCHE APOTHEKER UND ARZTEBANK EG..............     9,375,000.00     1.2500000000%        5,625,000      1.25000000%
                                                   ---------------   --------------   ---------------   -------------
                                                   $750,000,000.00   100.0000000000%  $450,000,000.00   100.000000000%
                                                   ===============   ==============   ===============   =============
</Table>
<PAGE>

                                 Schedule 11.02
                      to Revolving Loan Joinder Agreement

                     NEW REVOLVING LENDER NOTICE ADDRESSES
<PAGE>

                                  Exhibit A-1

                             [FORM OF] LOAN NOTICE

<Table>
<S>     <C>
Date:           ,

To:     Bank of America, N.A., as Administrative Agent

Re:     Amended and Restated Credit Agreement dated as of February
        21, 2003 (as further amended, restated, extended,
        supplemented or otherwise modified, the "Credit Agreement")
        among FRESENIUS MEDICAL CARE AG, FRESENIUS MEDICAL CARE
        HOLDINGS, INC. and FMC FINANCE II S.a.r.l., as Borrowers,
        the Guarantors party thereto, the Lenders party thereto, and
        BANK OF AMERICA, N.A., as Administrative Agent. Capitalized
        terms used herein and not otherwise defined have the
        meanings provided in the Credit Agreement.
</Table>

Ladies and Gentlemen:

The undersigned hereby requests (select one):

<Table>
        <S>                          <C>                             <C>
        [ ]  A Borrowing             [ ]  A conversion               [ ]  A continuation of Eurocurrency
                                                                       Rate Loans
</Table>

of (select one):


<Table>
        <S>                          <C>                             <C>
        [ ]  Revolving Loans



        [ ]  Tranche A-1 Term Loan



        1.  Date of Borrowing:
        -------------------------------------------------------------------------------------------------
            (a Business Day)



        2.  Currency:
        -------------------------------------------------------------------------------------------------



        3.  Amount:
        -------------------------------------------------------------------------------------------------



        4.  Type:
        -------------------------------------------------------------------------------------------------



        5.  Requested Interest Period (for Eurocurrency Rate Loans):
        -------------------------------------------------------------------------------------------------
</Table>

            With respect to any Borrowing, conversion or continuation requested
       herein, the undersigned Borrower hereby represents and warrants that (a)
       such request complies with the requirements of Sections 2.01 and 2.02 of
       the Credit Agreement, (b) the representations and warranties contained in
       Article VI of the Credit Agreement or in any other Credit Document, or
       that are contained in any document furnished at any time under or in
       connection therewith, shall be true and correct in all material respects
       on and as of the date hereof, except to the extent that such
       representations and warranties specifically refer to an earlier date, in
       which case they shall be true and correct in all material respects as of
       such earlier date, and except that for purposes hereof, the
       representations and warranties contained in subsections (a) and (b) of
       Section 6.05 of the Credit Agreement shall be deemed to refer to the most
       recent statements furnished pursuant to clauses (a) and (b),
       respectively, of Section 7.01 thereof, and (c) no Default or Event of
       Default shall exist, or would result from such proposed Credit Extension.

                                          Borrower:
                                               ---------------------------------

                                          By:
                                            ------------------------------------
                                            Name:
                                              Title:
<PAGE>

                                                              Exhibit C-6

                                                               [FORM OF]
                                                      TRANCHE A-1 TERM NOTE
                                                 [Date]

     FOR VALUE RECEIVED, each of the undersigned (the "Borrowers") hereby
jointly and severally promise to pay to [LENDER] or its registered assigns (the
"Lender"), in accordance with the provisions of that certain Amended and
Restated Credit Agreement dated as of February 21, 2003 (as further amended,
restated, extended, supplemented or otherwise modified from time to time, the
"Credit Agreement"), among the Borrowers, the Guarantors, the Lenders, and Bank
of America, N.A., as Administrative Agent, the principal amount of the Tranche
A-1 Term Loan made by the Lender to the Borrowers thereunder. Capitalized terms
used herein and not otherwise defined have the meanings provided in the Credit
Agreement.

     Each of the Borrowers jointly and severally promises to pay interest on the
unpaid principal amount of the Tranche A-1 Term Loan made by the Lender from the
date of such Tranche A-1 Term Loan until such principal amount is paid in full,
at the interest rates and at the times provided in the Credit Agreement. All
payments of principal and interest shall be made to the Administrative Agent for
the account of the Lender in immediately available funds at the Administrative
Agent's Office. If any amount is not paid in full when due hereunder, such
unpaid amount shall bear interest, to be paid upon demand, from the due date
thereof until the date of actual payment (and before as well as after judgment)
computed at the per annum rate set forth in the Credit Agreement.

     This Note is one of the Notes referred to in the Credit Agreement, is
entitled to the benefits thereof and may be prepaid in whole or in part subject
to the terms and conditions provided therein. Upon the occurrence and
continuation of one or more of the Events of Default specified in the Credit
Agreement, all amounts then remaining unpaid on this Note shall become, or may
be declared to be, immediately due and payable all as provided in the Credit
Agreement. The Tranche A-1 Term Loan made by the Lender shall be evidenced by
one or more loan accounts or records maintained by the Lender in the ordinary
course of business. The Lender may also attach schedules to this Note and
endorse thereon the date, amount and maturity of its Tranche A-1 Term Loan and
payments with respect thereto, and, absent manifest error, such schedules,
accounts or records shall be conclusive to the extent set forth in the Credit
Agreement.

     Each Borrower, for itself and its successors and assigns, hereby waives
diligence, presentment, protest and demand and notice of protest, demand,
dishonor and nonpayment of this Note.
<PAGE>

     THIS NOTE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF
THE STATE OF NEW YORK.

                                          FRESENIUS MEDICAL CARE AG, a German
                                          corporation

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FRESENIUS MEDICAL CARE HOLDINGS, INC.,
                                          a New York corporation

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:
<PAGE>

                                   Exhibit K

                        REVOLVING LOAN JOINDER AGREEMENT

     THIS REVOLVING LOAN JOINDER AGREEMENT (this "Agreement") dated as of
          to the Credit Agreement referenced below is by and among each of the
Persons identified as a "Revolving Lender" on the signature pages hereto (the
"New Revolving Lenders"), FRESENIUS MEDICAL CARE HOLDINGS, INC., a New York
corporation ("FMCH"), and FRESENIUS MEDICAL CARE AG, a German corporation
("FMCAG"), the other Borrowers identified in the Credit Agreement (together with
FMCH and FMCAG, the "Borrowers"), certain Subsidiaries and Affiliates of FMCAG,
as Guarantors, and BANK OF AMERICA, N.A., as administrative agent (in such
capacity, the "Administrative Agent") for the Lenders. All of the defined terms
of the Credit Agreement (as defined below) are incorporated herein by reference.

                              W I T N E S S E T H

     WHEREAS, there exists an Amended and Restated Credit Agreement dated as of
February 21, 2003 (as amended and modified from time to time, the "Credit
Agreement") among Fresenius Medical Care AG, a German corporation ("FMCAG"),
Fresenius Medical Care Holdings, Inc., a New York corporation ("FMCH"), certain
Subsidiaries and Affiliates of FMCAG identified therein, as borrowers and
guarantors, the lenders identified therein and Bank of America, N.A., as
Administrative Agent (the "Credit Agreement");

     WHEREAS, pursuant to Section 2.01(j) of the Credit Agreement, the Borrowers
have requested that each of the New Revolving Lenders provide an additional
Revolving Commitment under the Credit Agreement; and

     WHEREAS, each New Revolving Lender has agreed to provide an additional
Revolving Commitment on the terms and conditions set forth herein and to become
a "Revolving Lender" under the Credit Agreement in connection therewith;

     NOW, THEREFORE, IN CONSIDERATION of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

          1. Each New Revolving Lender severally agrees to provide an additional
     Revolving Commitment to the Borrowers from the date hereof through the end
     of the Commitment Period in the amount of its Revolving Committed Amount;
     provided that, after giving effect to this Agreement, (i) with regard to
     the Revolving Lenders (including the New Revolving Lenders) collectively,
     the Aggregate Revolving Committed Amount shall not exceed [SEVEN HUNDRED
     FIFTY MILLION DOLLARS ($750,000,000)] [NINE HUNDRED FIFTY MILLION DOLLARS
     ($950,000,000)]. The existing Schedule 2.01 to the Credit Agreement shall
     be deemed to be amended and replaced with Schedule 2.01 attached hereto,
     which has been revised to reflect the modified commitments and commitment
     percentages of the Revolving Lenders (including the New Revolving Lenders)
     pursuant to Section 2.01(j) of the Credit Agreement.

          2. Each New Revolving Lender shall be deemed to have purchased,
     without recourse, a risk participation from the L/C Issuers in all Letters
     of Credit issued or existing under the Credit Agreement and the obligations
     arising thereunder in an amount equal to its Revolving Commitment
     Percentage of the obligations under such Letters of Credit, and shall
     absolutely, unconditionally and irrevocably assume, as primary obligor and
     not as surety, and be obligated to pay to the L/C Issuers and discharge
     when due, its Revolving Commitment Percentage of the obligations arising
     under such Letters of Credit.

          3. Each New Revolving Lender (a) represents and warrants that it is an
     existing Revolving Lender under the Credit Agreement or a commercial
     lender, other financial institution or other "accredited" investor (as
     defined in SEC Regulation D) that makes or acquires loans in the ordinary
     course of business and that it will make or acquire Loans for its own
     account in the ordinary course of business; (b) confirms that it has
     received a copy of the Credit Agreement, together with copies of the
     financial statements referred to in Section 7.01 thereof and such other
     documents and information as it has deemed appropriate to make its own
     credit analysis and decision to enter into this Agreement; (c) agrees
<PAGE>

     that it will, independently and without reliance upon the Administrative
     Agent or any other Lender and based on such documents and information as it
     shall deem appropriate at the time, continue to make its own credit
     decisions in taking or not taking action under the Credit Agreement; (d)
     appoints and authorizes the Administrative Agent to take such action as
     agent on its behalf and to exercise such powers and discretion under the
     Credit Agreement as are delegated to the Administrative Agent by the terms
     thereof, together with such powers and discretion as are reasonably
     incidental thereto; and (e) agrees that, as of the date hereof, such New
     Revolving Lender shall (i) be a party to the Credit Agreement and the other
     Credit Documents, (ii) be a "Revolving Lender" for all purposes of the
     Credit Agreement and the other Credit Documents, (iii) perform all of the
     obligations that by the terms of the Credit Agreement are required to be
     performed by it as a "Lender" and a "Revolving Lender" under the Credit
     Agreement, (iv) shall have the rights and obligations of a Lender and a
     Revolving Lender under the Credit Agreement and the other Credit Documents,
     (v) agrees to be bound by the Parallel Debt Agreement, as amended or
     modified from time to time, or any substantially similar agreement that
     creates an obligation of the Credit Parties (as debt acknowledgement or
     abstraktes Schuldanerkenntnis) in favor of the Collateral Agent under
     German Law (under which a parallel debt structure has been created with a
     view to certain Pledge Agreements) and (vi) ratifies and approves all acts
     previously taken by the Collateral Agent on such New Revolving Lender's
     behalf (including the Collateral Agent acting as a proxy without power of
     attorney (Vertreter ohne Vertretungsmacht) in connection with any Pledge
     Agreement governed by German Law).

          4. Each of the Borrowers and the Guarantors agrees that, as of the
     date hereof, each of the New Revolving Lenders shall (i) be a party to the
     Credit Agreement and the other Credit Documents, (ii) be a "Lender" and a
     "Revolving Lender" for all purposes of the Credit Agreement and the other
     Credit Documents, and (iii) have the rights and obligations of a Lender and
     a Revolving Lender under the Credit Agreement and the other Credit
     Documents.

          5. The address of each New Revolving Lender for purposes of all
     notices and other communications shall be as provided on Schedule 11.02
     attached hereto, and Schedule 11.02 to the Credit Agreement is deemed
     amended to include the information on Schedule 11.02 attached hereto.

          6. This Agreement may be executed in any number of counterparts and by
     the various parties hereto in separate counterparts, each of which when so
     executed shall be deemed to be an original and all of which taken together
     shall constitute one contract. Delivery of an executed counterpart of this
     Agreement by telecopier shall be effective as delivery of a manually
     executed counterpart of this Agreement.

          7. This Agreement shall be governed by and construed and interpreted
     in accordance with the laws of the State of New York applicable to
     agreements made and to be performed entirely within such state.

                  [remainder of page intentionally left blank]
<PAGE>

     IN WITNESS WHEREOF, each of the parties hereto has caused this Agreement to
be executed by a duly authorized officer as of the date first above written.

<Table>
<S>                                            <C>
BORROWERS AND GUARANTORS:                      FRESENIUS MEDICAL CARE AG, a German
                                               corporation, as a Borrower and as a Guarantor
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FRESENIUS MEDICAL CARE HOLDINGS, INC.,
                                          a New York corporation, as a Borrower
                                          and as a Guarantor

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FMC FINANCE II S.a.r.l., a private
                                          limited company (societe a
                                          responsabilite limitee) organized
                                          under the laws of Luxembourg, as a
                                          Borrower and as a Guarantor

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    NATIONAL MEDICAL CARE, INC., a Delaware
                                               corporation
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FRESENIUS MEDICAL CARE DEUTSCHLAND
                                          GmbH, a German corporation

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FMC TRUST FINANCE S.a.r.l. LUXEMBOURG,
                                          a private limited company (societe a
                                          responsabilite limitee) organized
                                          under the laws of Luxembourg

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FMC TRUST FINANCE S.a.r.l.
                                          LUXEMBOURG-III, a private limited
                                          company (societe a responsabilite
                                          limitee) organized under the laws of
                                          Luxembourg

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    BIO-MEDICAL APPLICATIONS MANAGEMENT COMPANY,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF ARIZONA, INC., a
                                               Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF CALIFORNIA, INC.,
                                               a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF LOUISIANA, LLC, a
                                               Delaware limited liability company,
                                               BIO-MEDICAL APPLICATIONS OF MAINE, INC., a
                                               Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF NEW MEXICO, INC.,
                                               a Delaware corporation,
                                               FMS NEW YORK, INC., a Delaware corporation
                                               formerly known as Bio-Medical Applications of
                                               New York, Inc.
                                               BIO-MEDICAL APPLICATIONS OF NORTH CAROLINA,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF PENNSYLVANIA,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF SOUTH CAROLINA,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF TEXAS, INC., a
                                               Delaware corporation,
                                               EVEREST HEALTHCARE HOLDINGS, INC., a Delaware
                                               corporation,
                                               FRESENIUS USA MANUFACTURING, INC., a Delaware
                                               corporation,
                                               FRESENIUS USA MARKETING, INC., a Delaware
                                               corporation,
                                               FRESENIUS USA, INC., a Massachusetts
                                               corporation,
                                               SPECTRA LABORATORIES, INC., a Nevada
                                               corporation
</Table>

                                          By:
                                            ------------------------------------
                                            Name:
                                              Title:
                                                 for each of the foregoing
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    NMC A, LLC, a Delaware limited liability
                                               company
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FRESENIUS MEDICAL CARE US
                                          BETEILIGUNGSGESELLSCHAFT mbH, a German
                                          limited liability company

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FRESENIUS MEDICAL CARE
                                          BETEILIGUNGSGESELLSCHAFT mbH, a German
                                          limited liability company

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    FRESENIUS MEDICAL CARE US ZWEI
                                               BETEILIGUNGSGESELLSCHAFT mbH, a German limited
                                               liability company, formerly known as Gabriele
                                               41 Vermogensverwaltung GmbH
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FRESENIUS MEDICAL CARE US DREI
                                          BETEILIGUNGSGESELLSCHAFT mbH, a German
                                          limited liability company

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

<Table>
<S>                                            <C>
NEW REVOLVING LENDERS:
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

<Table>
<S>                                            <C>
ADMINISTRATIVE AGENT:                          BANK OF AMERICA, N.A., as Administrative Agent
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:
<PAGE>

                                 Schedule 2.01

                REVOLVING COMMITMENTS AND COMMITMENT PERCENTAGES
                      to Revolving Loan Joinder Agreement

<Table>
<Caption>
                                                                                  REVOLVING
                                                                 REVOLVING       COMMITMENT
REVOLVING LENDER                                                COMMITMENT       PERCENTAGE
----------------                                              ---------------   -------------
<S>                                                           <C>               <C>
Totals:.....................................................  $750,000,000.00   100.000000000%
</Table>
<PAGE>

                                 Schedule 11.02
                      to Revolving Loan Joinder Agreement

                     NEW REVOLVING LENDER NOTICE ADDRESSES
<PAGE>

                                   Exhibit L

                                   [FORM OF]
                    TRANCHE A-1 TERM LOAN JOINDER AGREEMENT

     THIS TRANCHE A-1 TERM LOAN JOINDER AGREEMENT (this "Agreement") dated as of
December 10, 2004 to the Credit Agreement referenced below is by and among the
Tranche A-1 Term Lenders identified on the signature pages hereto (the "Tranche
A-1 Term Lenders"), FRESENIUS MEDICAL CARE HOLDINGS, INC., a New York
corporation ("FMCH"), and FRESENIUS MEDICAL CARE AG, a German corporation
("FMCAG"; together with FMCH, each a "Tranche A-1 Term Loan Borrower" and,
collectively, the "Tranche A-1 Term Loan Borrowers"), certain Subsidiaries and
Affiliates of FMCAG, as Guarantors, and BANK OF AMERICA, N.A., as administrative
agent (in such capacity, the "Administrative Agent") for the Lenders. All of the
defined terms of the Credit Agreement (as defined below) are incorporated herein
by reference.

                              W I T N E S S E T H

     WHEREAS, there exists an Amended and Restated Credit Agreement dated as of
February 21, 2003 (as amended and modified from time to time, the "Credit
Agreement") among Fresenius Medical Care AG, a German corporation ("FMCAG"),
Fresenius Medical Care Holdings, Inc., a New York corporation ("FMCH"), certain
Subsidiaries and Affiliates of FMCAG identified therein, as borrowers and
guarantors, the lenders identified therein and Bank of America, N.A., as
Administrative Agent (the "Credit Agreement");

     WHEREAS, pursuant to Section 2.01(f-1) of the Credit Agreement, the Tranche
A-1 Term Loan Borrowers have requested that the Tranche A-1 Term Lenders provide
a Tranche A-1 Term Loan under the Credit Agreement; and

     WHEREAS, each Tranche A-1 Term Lender has agreed to make a portion of the
Tranche A-1 Term Loan on the terms and conditions set forth herein and to become
a "Tranche A-1 Term Lender" under the Credit Agreement in connection therewith;

     NOW, THEREFORE, IN CONSIDERATION of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

          1. The initial Tranche A-1 Term Loan Commitments and Tranche A-1 Term
     Loan Commitment Percentages are set forth on Schedule 2.01 attached hereto.
     Further, Schedule 2.01 to the Credit Agreement is deemed amended to include
     the information on the Tranche A-1 Term Loan Commitments and the Tranche
     A-1 Term Loan Commitment Percentages provided on Schedule 2.01 attached
     hereto.

          2. Subject to the terms and conditions set forth herein, on the date
     hereof, each of the Tranche A-1 Term Lenders severally agrees to make its
     portion of the Tranche A-1 Term Loan (in the amount of its respective
     Tranche A-1 Term Loan Committed Amount as set forth on Schedule 2.01
     attached hereto) consisting of an advance in Dollars in the aggregate
     principal amount of FOUR HUNDRED FIFTY MILLION DOLLARS ($450,000,000)
     consisting of a single advance to FMCAG in the amount of $245,000,000 and a
     single advance to FMCH in the amount of $205,000,000. The Tranche A-1 Term
     Loan may consist of Base Rate Loans, Eurocurrency Rate Loans or a
     combination thereof, as the applicable Borrower may request. Amounts repaid
     on the Tranche A-1 Term Loan may not be reborrowed.

          3. The Applicable Percentage for the Tranche A-1 Term Loan shall be as
     provided in the Credit Agreement.

          4. The Tranche A-1 Term Loan shall be payable in quarterly
     installments as provided in the Credit Agreement.

          5. Each Tranche A-1 Term Lender (a) represents and warrants that it is
     a commercial lender, other financial institution or other "accredited"
     investor (as defined in SEC Regulation D) that makes or
<PAGE>

     acquires loans in the ordinary course of business and that it will make or
     acquire Loans for its own account in the ordinary course of business; (b)
     confirms that it has received a copy of the Credit Agreement, together with
     copies of the financial statements referred to in Section 7.01 thereof and
     such other documents and information as it has deemed appropriate to make
     its own credit analysis and decision to enter into this Agreement; (c)
     agrees that it will, independently and without reliance upon the
     Administrative Agent or any other Lender and based on such documents and
     information as it shall deem appropriate at the time, continue to make its
     own credit decisions in taking or not taking action under the Credit
     Agreement; (d) appoints and authorizes the Administrative Agent to take
     such action as agent on its behalf and to exercise such powers and
     discretion under the Credit Agreement as are delegated to the
     Administrative Agent by the terms thereof, together with such powers and
     discretion as are reasonably incidental thereto; (e) agrees that, as of the
     date hereof, such Tranche A-1 Term Lender shall (i) be a party to the
     Credit Agreement and the other Credit Documents, (ii) be a "Tranche A-1
     Term Lender" for all purposes of the Credit Agreement and the other Credit
     Documents, (iii) perform all of the obligations that by the terms of the
     Credit Agreement are required to be performed by it as a "Lender" and a
     "Tranche A-1 Term Lender" under the Credit Agreement, (iv) shall have the
     rights and obligations of a Lender and a Tranche A-1 Term Lender under the
     Credit Agreement and the other Credit Documents, (v) agrees to be bound by
     the Parallel Debt Agreement, as amended or modified from time to time, or
     any substantially similar agreement that creates an obligation of the
     Credit Parties (as debt acknowledgement or abstraktes Schuldanerkenntnis)
     in favor of the Collateral Agent under German Law (under which a parallel
     debt structure has been created with a view to certain Pledge Agreements)
     and (vi) ratifies and approves all acts previously taken by the Collateral
     Agent on such Tranche A-1 Term Lender's behalf (including the Collateral
     Agent acting as a proxy without power of attorney (Vertreter ohne
     Vertretungsmacht) in connection with any Pledge Agreement governed by
     German Law); and (f) agrees to waive the borrowing notice provisions of
     Section 2.02(a) of the Credit Agreement with respect to the advance of the
     Tranche A-1 Term Loan on the date hereof.

          6. Each of the Tranche A-1 Term Loan Borrowers and the Guarantors
     agrees that, as of the date hereof, each of the Tranche A-1 Term Lenders
     shall (i) be a party to the Credit Agreement and the other Credit
     Documents, (ii) be a "Lender" and a "Tranche A-1 Term Lender" for all
     purposes of the Credit Agreement and the other Credit Documents, and (iii)
     have the rights and obligations of a Lender and a Tranche A-1 Term Lender
     under the Credit Agreement and the other Credit Documents.

          7. The address of each Tranche A-1 Term Lender for purposes of all
     notices and other communications shall be as provided on Schedule 11.02
     attached hereto, and Schedule 11.02 to the Credit Agreement is deemed
     amended to include the information on Schedule 11.02 attached hereto.

          8. This Agreement may be executed in any number of counterparts and by
     the various parties hereto in separate counterparts, each of which when so
     executed shall be deemed to be an original and all of which taken together
     shall constitute one contract. Delivery of an executed counterpart of this
     Agreement by telecopier shall be effective as delivery of a manually
     executed counterpart of this Agreement.

          9. This Agreement shall be governed by and construed and interpreted
     in accordance with the laws of the State of New York applicable to
     agreements made and to be performed entirely within such state.

                  [remainder of page intentionally left blank]
<PAGE>

     IN WITNESS WHEREOF, each of the parties hereto has caused this Agreement to
be executed by a duly authorized officer as of the date first above written.

<Table>
<S>                                            <C>
BORROWERS AND GUARANTORS:                      FRESENIUS MEDICAL CARE AG, a German
                                               corporation, as a Borrower and as a Guarantor
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FRESENIUS MEDICAL CARE HOLDINGS, INC.,
                                          a New York corporation, as a Borrower
                                          and as a Guarantor

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    NATIONAL MEDICAL CARE, INC., a Delaware
                                               corporation
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FRESENIUS MEDICAL CARE DEUTSCHLAND
                                          GmbH, a German corporation

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FMC FINANCE II S.a.r.l., a private
                                          limited company (societe a
                                          responsabilite limitee) organized
                                          under the laws of Luxembourg

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FMC TRUST FINANCE S.a.r.l. LUXEMBOURG,
                                          a private limited company (societe a
                                          responsabilite limitee) organized
                                          under the laws of Luxembourg

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FMC TRUST FINANCE S.a.r.l.
                                          LUXEMBOURG-III, a private limited
                                          company (societe a responsabilite
                                          limitee) organized under the laws of
                                          Luxembourg

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    BIO-MEDICAL APPLICATIONS MANAGEMENT COMPANY,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF ARIZONA, INC., a
                                               Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF CALIFORNIA, INC.,
                                               a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF LOUISIANA, LLC, a
                                               Delaware limited liability company,
                                               BIO-MEDICAL APPLICATIONS OF MAINE, INC., a
                                               Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF NEW MEXICO, INC.,
                                               a Delaware corporation,
                                               FMS NEW YORK, INC., a Delaware corporation
                                               formerly known as Bio-Medical Applications of
                                               New York, Inc.
                                               BIO-MEDICAL APPLICATIONS OF NORTH CAROLINA,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF PENNSYLVANIA,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF SOUTH CAROLINA,
                                               INC., a Delaware corporation,
                                               BIO-MEDICAL APPLICATIONS OF TEXAS, INC., a
                                               Delaware corporation,
                                               EVEREST HEALTHCARE HOLDINGS, INC., a Delaware
                                               corporation,
                                               FRESENIUS USA MANUFACTURING, INC., a Delaware
                                               corporation,
                                               FRESENIUS USA MARKETING, INC., a Delaware
                                               corporation,
                                               FRESENIUS USA, INC., a Massachusetts
                                               corporation,
                                               SPECTRA LABORATORIES, INC., a Nevada
                                               corporation
</Table>

                                          By:
                                            ------------------------------------
                                            Name:
                                              Title:
                                                 for each of the foregoing
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    NMC A, LLC, a Delaware limited liability
                                               company
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FRESENIUS MEDICAL CARE US
                                          BETEILIGUNGSGESELLSCHAFT mbH, a German
                                          limited liability company

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FRESENIUS MEDICAL CARE
                                          BETEILIGUNGSGESELLSCHAFT mbH, a German
                                          limited liability company

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:
<PAGE>

<Table>
<S>                                            <C>
GUARANTORS:                                    FRESENIUS MEDICAL CARE US ZWEI
                                               BETEILIGUNGSGESELLSCHAFT mbH, a German limited
                                               liability company, formerly known as Gabriele
                                               41 Vermogensverwaltung GmbH
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

                                          FRESENIUS MEDICAL CARE US DREI
                                          BETEILIGUNGSGESELLSCHAFT mbH, a German
                                          limited liability company

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:
<PAGE>

<Table>
<S>                                            <C>
TRANCHE A-1 TERM LENDERS:
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:

<Table>
<S>                                            <C>
ADMINISTRATIVE AGENT:                          BANK OF AMERICA, N.A., as Administrative Agent
</Table>

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title:
<PAGE>

                                 Schedule 2.01
                   to Tranche A-1 Term Loan Joinder Agreement

          TRANCHE A-1 TERM LOAN COMMITMENTS AND COMMITMENT PERCENTAGES

<Table>
<Caption>
-------------------------------------------------------------------------------------------------
                                                                                   TRANCHE A-1
                                                                TRANCHE A-1         TERM LOAN
                                                                 TERM LOAN          COMMITMENT
TRANCHE A-1 LENDER                                              COMMITMENT          PERCENTAGE
-------------------------------------------------------------------------------------------------
<S>                                                          <C>                 <C>
Totals:....................................................  [$450,000,000.00]    100.000000000%
-------------------------------------------------------------------------------------------------
</Table>
<PAGE>

                           CONSENT TO AMENDMENT NO. 3

Bank of America, N.A.,
as Administrative Agent
1455 Market Street
CA5-701-05-19
San Francisco, California 94103
Attn: Cassandra G. McCain, Agency Management

     Re:  Credit Agreement dated as of February 21, 2003 (as amended and
          modified, the "Credit Agreement") among Fresenius Medical Care AG,
          Fresenius Medical Care Holdings, Inc., the other Borrowers, Guarantors
          and Lenders identified therein and Bank of America, N.A., as
          Administrative Agent. Capitalized terms used but not otherwise defined
          shall have the meanings provided in the Credit Agreement.

          Amendment No. 3 dated December 10, 2004 (the "Subject Amendment") to
          the Credit Agreement.

Ladies and Gentlemen:

This should serve to confirm our receipt of, and consent to, the Subject
Amendment. We hereby (i) authorize and direct you, as Administrative Agent for
the Lenders, to enter into the Subject Amendment on our behalf in accordance
with the terms of the Credit Agreement upon your receipt of such consent and
direction from the Required Lenders, the requisite Revolving Lenders and the
requisite Tranche A Term Lenders, and (ii) agree that the Borrowers and the
other Credit Parties may rely on such authorization.

                                          Sincerely,

                                          --------------------------------------
                                                     [Name of Lender]

                                          By:
                                            ------------------------------------
                                              Name:
                                            Title: