<PAGE>   1
                                                                    EXHIBIT 10.1


                                 AMENDMENT NO. 3

                          DATED AS OF OCTOBER 14, 1999

                                       TO

                           LOAN AND SECURITY AGREEMENT

                                   AS AMENDED

                            DATED AS OF JUNE 5, 1997

                                      AMONG

                ACCREDO HEALTH, INCORPORATED AND ITS SUBSIDIARIES

                                       AND

                             BANK OF AMERICA, N.A.,

                    FIRST TENNESSEE BANK NATIONAL ASSOCIATION

                                       AND

                          BROWN BROTHERS HARRIMAN & CO.

                                       AND

                         BANK OF AMERICA, N.A., AS AGENT



<PAGE>   2



                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                Page
                                                                                ----

<S>      <C>                                                                    <C>
 1.      Definitions..............................................................1

 2.      Amendments to Agreement..................................................1

 3.      Representations and Warranties...........................................2
         3.1.     Incorporation...................................................2
         3.2.     Due Authorization, No Conflicts, Etc............................2
         3.3.     Due Execution, Etc..............................................2

 4.      Conditions Precedent.....................................................3
         4.1.     Conditions Precedent to Effectiveness of Amendment No. 3........3

 5.      Effectiveness of Amendment No. 3.........................................4

 6.      Closing..................................................................4

 7.      Governing Law, Etc.......................................................4

 8.      Section Titles and Table of Contents.....................................4

 9.      Waiver of Jury Trial.....................................................4

10.      Counterparts.............................................................4

11.      Agreement to Remain in Effect............................................5
</TABLE>







<PAGE>   3



                  AMENDMENT NO. 3 dated as of October 14, 1999 under and to that
certain Loan and Security Agreement dated as of June 5, 1997 as amended by
Amendment No. 1 dated August 28, 1998 and further amended by Amendment No. 2
dated March 1, 1999 (collectively, the "Agreement"), among Accredo Health,
Incorporated (formerly Nova Holdings, Inc.), a Delaware corporation (the
"Borrower"); the Guarantors, jointly and severally; each of the undersigned
Banks (in such capacity, the "Banks"), and Bank of America, N.A. (successor to
NationsBank, N.A.), as Agent for the Banks (in such capacity, the "Agent").

                              W I T N E S S E T H :

                  WHEREAS, the Borrower, the Guarantors, the Banks and the Agent
are parties to the Agreement; and

                  WHEREAS, Nova Factor, Inc., a subsidiary of Southern Health
Systems, Inc. which is itself a subsidiary of Accredo Health, Incorporated, has
formed a new subsidiary, being a Tennessee corporation known as AHI Pharmacies,
Inc.; and

                  WHEREAS, the formation of such additional subsidiary requires
the consent of the Banks, which consent the Banks hereby grant subject to the
conditions and provisions of this Amendment No. 3 being satisfied as hereinafter
set forth;

                  NOW THEREFORE, in consideration of the foregoing and the
mutual covenants and agreements set forth herein, and for other good and
valuable consideration, the receipt and legal sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

                  1.       DEFINITIONS. All capitalized terms used in this
Amendment No. 3 which are not otherwise defined herein shall have the respective
meanings ascribed thereto in the Agreement.

                  2.       AMENDMENTS TO AGREEMENT.

                           2.1.     Section I of the Agreement, DEFINITIONS, is
hereby amended by adding thereto the following new definitions as follows:

                           "AMENDMENT NO. 3 EFFECTIVE DATE" has the meaning
                  specified in Section 5 of this Amendment No. 3.

In addition to the foregoing new definition, the following definition is hereby
amended:

                  "Guarantor" is hereby amended to replace the period after
subparagraph (C)
<PAGE>   4
with a comma, and to add a subparagraph (D) as follows:

                           "(D) AHI Pharmacies, Inc., a Tennessee corporation".

                           2.2.     AHI Pharmacies, Inc., a Tennessee
corporation, hereby agrees to become a party to the Agreement as a Guarantor
thereunder, and hereby grants and confirms the grant of the security interest
contained therein.

                  3.       REPRESENTATIONS AND WARRANTIES. To induce the Banks
and the Agent to enter into this Amendment No. 3, Borrower and Guarantors
jointly and severally represent and warrant to the Banks and the Agent as
follows:

                           3.1.     INCORPORATION. Accredo Health, Incorporated
is a corporation duly organized, validly existing and in good standing under the
laws of the State of Delaware, and is qualified to transact business in the
State of Tennessee; Nova Factor, Inc., Southern Health Systems, Inc., Hemophilia
Health Services (successor to Horizon Health Systems, Inc.) and AHI Pharmacies,
Inc. are corporations duly organized, validly existing and in good standing
under the laws of the State of Tennessee; each of the foregoing corporations has
the lawful power to own its properties and to engage in the business it now
conducts, and each is duly qualified and in good standing as a foreign
corporation in the jurisdictions wherein the nature of the business transacted
by it or property owned by it is both material and makes qualification
necessary; Accredo Health, Incorporated has its chief executive office and
principal place of business in Memphis, Tennessee, and each of the other
corporations has its chief executive office and principal place of business
located in either Nashville, Tennessee, or Memphis, Tennessee.

                           3.2.     DUE AUTHORIZATION, NO CONFLICTS, ETC. The
execution, delivery and performance by the Borrower and Guarantors of this
Amendment No. 3 and any and all other agreements, instruments and documents to
be executed and/or delivered by the Borrower or any Guarantor pursuant hereto or
in connection herewith, and the consummation by Borrower and Guarantors of the
transactions contemplated hereby or thereby: (a) are within the corporate powers
of each; (b) have been duly authorized by all necessary corporate action,
including without limitation, the consent of stockholders where required; (c) do
not and will not (i) contravene the respective certificate of incorporation or
by-laws or other comparable governing documents of Borrower or any Guarantor,
(ii) violate any Laws, or any order or decree of any court or governmental
authority, or (iii) conflict with or result in the breach of, or constitute a
default under, or result in the termination of, any material contractual
obligation of Borrower or any Guarantor, and (d) do not require the consent,
authorization by, or approval of, or notice to, or filing or registration with,
any governmental authority or any other Person other than those which have been
obtained and copies of which have been delivered to the Agent pursuant to
Subsection 4.1(a)(ii) hereof, each of which is in full force and effect.



                                       2
<PAGE>   5

                           3.3.     DUE EXECUTION, ETC. This Amendment No. 3 and
each of the other agreements, instruments and documents to be executed and/or
delivered by Borrower or any Guarantor pursuant hereto or in connection herewith
(a) has been duly executed and delivered, and (b) constitutes the legal, valid
and binding obligation of each, enforceable against it in accordance with its
terms, subject however to state and federal bankruptcy, insolvency,
reorganization and other laws and general principles of equity affecting
enforcement of the rights of creditors generally.

                  4.       CONDITIONS PRECEDENT. The effectiveness of this
Amendment No. 3 is subject to the fulfillment of the following conditions
precedent on or prior to the Amendment No. 3 Effective Date (as hereinafter
defined in Section 5 hereof):

                           4.1.     CONDITIONS PRECEDENT TO EFFECTIVENESS OF
AMENDMENT NO. 3. The Agent shall have received, on or prior to the Amendment No.
3 Effective Date, the following, each dated on or prior to the Amendment No. 3
Effective Date unless otherwise indicated, in form and substance satisfactory to
the Agent and in sufficient copies for each Bank:

                                    (a)      Certified copies of (i) the
resolutions of the Board of Directors of Borrower and each Guarantor approving
this Amendment No. 3 and each other agreement, instrument or document to be
executed by them pursuant hereto or as contemplated hereby, and (ii) all
documents evidencing other necessary corporate action and required governmental
and third party approvals, licenses and consents with respect to this Amendment
No. 3 and the transactions contemplated hereby.

                                    (b)      A certificate of the Secretary or
an Assistant Secretary of Borrower and each Guarantor certifying the names and
true signatures of the officers of Borrower and each Guarantor who have been
authorized to execute on behalf of Borrower and such Guarantor this Amendment
No. 3 and any other agreement, instrument or document executed or to be executed
by Borrower and any Guarantor in connection herewith.

                                    (c)      A certificate dated the Amendment
No. 3 Effective Date signed by the President or any Vice-President of Borrower,
to the following effect:

                                    (i)      The representations and warranties
                  of the Borrower contained in Sections 3.1, 3.2 and 3.3 of this
                  Amendment No. 3 are true and correct on and as of such date as
                  though made on and as of such date;

                                    (ii)     No Default or Event of Default has
                  occurred and is continuing, and no Default or Event of Default
                  would result from the execution and delivery of this Amendment
                  No. 3 or the other agreements, instruments and documents
                  contemplated hereby; and



                                       3
<PAGE>   6

                                    (iii)    The Borrower has paid or agreed to
                  pay all amounts payable by it pursuant to the Agreement as
                  amended hereby (including, without limitation, all legal fees
                  and expenses of Banks' counsel incurred in connection
                  herewith) to the extent then due and payable.

                                    (d)      Original Guaranty and Suretyship
Agreements duly executed by AHI Pharmacies, Inc. in the form attached hereto as
EXHIBIT F-1.

                                    (e)      Such UCC financing statements and
amendments thereto (including to pay additional Tennessee Privilege Taxes) as
may be required by the Banks.

                                    (f)      Original Stock Pledge Agreement
duly executed by Nova Factor, Inc. in the form attached hereto as Exhibit E-1
together with the original of all outstanding stock certificates held by Nova
Factor, Inc. in AHI Pharmacies, Inc., together with such blank stock powers as
may be required by the Agent.

                  5.       EFFECTIVENESS OF AMENDMENT NO. 3. This Amendment No.
3 and the Exhibits attached hereto shall become effective at such time as (a)
each of the conditions precedent set forth in Section 4.1 hereof shall have been
satisfied, and (b) counterparts of this Amendment No. 3, executed and delivered
by the Borrower, the Guarantors, the Banks and the Agent shall have been
received by the Agent (or, alternatively, confirmation of the execution hereof
by such parties shall have been received by the Agent). The date upon which the
conditions described in clauses (a) and (b) of the foregoing sentence shall have
been fulfilled is referred to herein as the "Amendment No. 3 Effective Date".

                  6.       CLOSING. The Closing under this Amendment No. 3 shall
occur on the Amendment Effective Date at the offices of Boult, Cummings, Conners
& Berry, PLC, 414 Union Street, Nashville, Tennessee 37219, or such other
location as the parties may agree.

                  7.       GOVERNING LAW, ETC. This Amendment No. 3 shall be
governed by, and construed in accordance with, the laws of the State of
Tennessee as provided in Section 10.9 of the Agreement, which Section is
incorporated herein by reference and made a part hereof as though set forth in
full herein.

                  8.       SECTION TITLES AND TABLE OF CONTENTS. The Section
Titles and Table of Contents contained in this Amendment No. 3 are and shall be
without substantive meaning or content of any kind whatsoever and are not a
part of the agreement among the parties hereto.

                  9.       WAIVER OF JURY TRIAL. EACH PARTY HERETO, INCLUDING
THE BORROWER, EACH SUBSIDIARY, THE BANKS, AND THE AGENT, HEREBY KNOWINGLY,
VOLUNTARILY AND INTENTIONALLY WAIVE (TO THE EXTENT PERMITTED BY APPLICABLE LAWS)
ANY RIGHTS THEY MAY HAVE TO A TRIAL BY JURY OF ANY DISPUTE ARISING UNDER,
RELATING TO, OR CONNECTED


                                       4
<PAGE>   7

WITH THIS AGREEMENT, THE COLLATERAL OR ANY OTHER AGREEMENT, INSTRUMENT OR
DOCUMENT CONTEMPLATED HEREBY OR DELIVERED IN CONNECTION HEREWITH AND AGREE THAT
ANY SUCH DISPUTE SHALL BE TRIED BEFORE A JUDGE SITTING WITHOUT A JURY. THIS
PROVISION IS A MATERIAL INDUCEMENT FOR THE BANKS' AND THE AGENT ENTERING INTO
THIS AGREEMENT.

                  10.      COUNTERPARTS. This Amendment No. 3 may be executed in
any number of counterparts and by different 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 and the same instrument.

                  11.      AGREEMENT TO REMAIN IN EFFECT. Except as expressly
provided herein, the Agreement and each other Collateral Document shall be and
shall continue in full force and effect in accordance with its respective terms.

                  IN WITNESS WHEREOF, the parties hereto have caused this
Amendment No. 3 to be executed by their respective officers thereunto duly
authorized, as of the date first above written.

AGENT                                        BORROWER

BANK OF AMERICA, N.A.,                       ACCREDO HEALTH, INCORPORATED
as Agent



BY:                                          BY:
   -------------------------------              -------------------------------
TITLE:                                       TITLE:
      ----------------------------                 ----------------------------

BANKS                                        GUARANTORS AND SUBSIDIARIES

BANK OF AMERICA, N.A.                        SOUTHERN HEALTH SYSTEMS, INC.



BY:                                          BY:
   -------------------------------              -------------------------------

TITLE:                                       TITLE:
      ----------------------------                 ----------------------------







                                       5
<PAGE>   8

FIRST TENNESSEE BANK NATIONAL                NOVA FACTOR, INC.
ASSOCIATION


BY:                                          BY:
   -------------------------------              -------------------------------

TITLE:                                       TITLE:
      ----------------------------                 ----------------------------



BROWN BROTHERS HARRIMAN & CO. HEMOPHILIA HEALTH SERVICES, INC.
                                 (successor to Horizon Health Systems, Inc.)


BY:                                          BY:
   -------------------------------              -------------------------------

TITLE:                                       TITLE:
      ----------------------------                 ----------------------------


                                             AHI PHARMACIES, INC.


                                             BY:
                                                -------------------------------

                                             TITLE:
                                                   ----------------------------

















                                        6