<PAGE>   1
                                                                   EXHIBIT 10.64


                             SUBORDINATION AGREEMENT

                           Dated as of March 29, 2000

                                      Among

                          WATSON PHARMACEUTICALS, INC.,

                             HALSEY DRUG CO., INC.,

                              The Existing Holders
                               (as defined herein)

                                       and

                    THE GRANTORS AND GUARANTORS NAMED HEREIN


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                                TABLE OF CONTENTS

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<S>                       <C>                                                                                                <C>

ARTICLE I                  DEFINITIONS........................................................................................2

      SECTION 1.1.                  Definitions of Certain Terms..............................................................2
      SECTION 1.2.                  Terms Generally...........................................................................3

ARTICLE II                 STANDBY AND SUBORDINATION..........................................................................4


ARTICLE III                PAYMENTS...........................................................................................4


ARTICLE IV                 SECURITY INTEREST SUBORDINATION....................................................................5


ARTICLE V                  DISPOSITION OF COLLATERAL..........................................................................5


ARTICLE VI                 SENIOR DEBT........................................................................................5


ARTICLE VII                DEFAULT............................................................................................6


ARTICLE VIII               NO COMMITMENT......................................................................................6


ARTICLE IX                 NO CONTEST.........................................................................................6


ARTICLE X                  FINANCIAL CONDITION OF BORROWER....................................................................6


ARTICLE XI                 REVIVOR............................................................................................6


ARTICLE XII                REPRESENTATIONS AND WARRANTIES.....................................................................7

      SECTION 12.1.                 Representations and Warranties of the Existing Holders....................................7
      SECTION 12.2.                 Representations and Warranties of Each Party..............................................7

ARTICLE XIII               EXISTING INTERCREDITOR AGREEMENT...................................................................7


ARTICLE XIV                MISCELLANEOUS......................................................................................7

      SECTION 14.1.                 No Individual Action......................................................................7
      SECTION 14.2.                 Successors and Assigns....................................................................7
      SECTION 14.3.                 Notices...................................................................................7
      SECTION 14.4.                 Termination...............................................................................8
      SECTION 14.5.                 Applicable Law............................................................................8
      SECTION 14.6.                 Amendments and Waivers of Agreement and Support Documents.................................8
      SECTION 14.7.                 Waiver of Rights..........................................................................8
      SECTION 14.8.                 Severability..............................................................................8

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     <S>                                <C>                                                                                   <C>

      SECTION 14.9.                 Waiver of Jury Trial.......................................................................9
      SECTION 14.10.                Counterparts; Effectiveness................................................................9
      SECTION 14.11.                Section Headings...........................................................................9
      SECTION 14.12.                Complete Agreement.........................................................................9


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                             SUBORDINATION AGREEMENT

        This SUBORDINATION AGREEMENT (the "Agreement") is dated as of March 29,
2000 and is entered into by and among (i) WATSON PHARMACEUTICALS, INC., a
Nevada corporation ("Watson"), (ii) HALSEY DRUG CO., INC., a New York
corporation (the "Company"), (iii) the holders of the 5% Convertible Senior
Secured Debentures issued by the Company pursuant to the Debenture and Warrant
Purchase Agreement, dated March 10, 1998 (the "Galen Debenture Agreement"), by
and among the Company, Galen Partners III, L.P. and the other signatories
thereto, listed on Schedule 4 attached hereto (such holders, the "GALEN INVESTOR
GROUP"), (iv) the holders of the 5% Convertible Senior Secured Debentures issued
by the Company pursuant to the Debenture and Warrant Purchase Agreement, dated
May 26, 1999 (the "Oracle Debenture Agreement"), by and among the Company,
Oracle Strategic Partners, L.P. and the other signatories thereto, listed on
Schedule 4 attached hereto (such holders, the "ORACLE INVESTOR GROUP"), and (v)
the Grantors and Guarantors listed on the signature pages hereof. Certain
capitalized terms used herein have the meanings ascribed thereto in Section
1.1.

                                    RECITALS

        A.      Watson and the Company have entered into that certain Loan
Agreement, dated as of March 29, 2000 (the "Loan Agreement"), pursuant to which
Watson agreed to loan the Company the principal amount of Seventeen Million Five
Hundred Thousand Dollars ($17,500,000) (the "Loan").

        B.      The Company has issued its 5% Convertible Senior Secured
Debentures Due March 15, 2003 to the Galen Investor Group pursuant to the Galen
Debenture Agreement (such debentures, the "Galen Debentures") and to the Oracle
Investor Group pursuant to the Oracle Debenture Agreement (such debentures, the
"Oracle Debentures," and collectively with the Galen Debentures, the "Existing
Debentures"). The holders of the Existing Debentures as of a given date are
sometimes referred to herein as the "Existing Holders", and the Existing Holders
and Watson are sometimes referred to herein collectively as the "Secured
Creditors".

        C.      The Company and certain of its affiliates have entered into the
Existing Security Documents and Existing Guaranty Agreements pursuant to which
the Company and such affiliates secured the Company's obligations under the
Existing Debentures and guarantied the payment and performance of such
obligations.

        D.      In connection with the execution of the Loan Agreement, the
Company and Watson will be entering into new security documents (the "Watson
Security Documents").

        E.      As an inducement to make the Loan, the Galen Investor Group and
the Oracle Investor Group agree that (i) as among the Secured Creditors,
Watson's security interest in the Collateral shall rank first in priority among
the Secured Creditors; and (ii) proceeds received from enforcement of the Watson
Security Documents and the Existing Security Documents will be applied first to
the payment of the Company's obligations in respect of the Loan, and second, to
the extent of any remaining proceeds, to the payment of the Company's
obligations in respect of the Existing Debentures. The Company's and its
affiliates' obligations under the Loan and the Existing Debentures are sometimes
referred to collectively herein as the "Secured Obligations".

        F.      The parties hereto desire to set forth their agreement regarding
the priority of Watson's security interest and the application to the Secured
Obligations of cash received by the


                                       1
<PAGE>   5
Secured Creditors from dispositions of Collateral and the enforcement of the
Existing Security Documents and the Watson Security Documents and the agreement
of Watson, the Galen Investor Group and the Oracle Investor Group as to the
decisions relating to the exercise of remedies under this Agreement and the
Existing Security Documents and the Watson Security Documents.

            G. It is a condition precedent to the effectiveness of the Loan
Agreement that Watson, the Galen Investor Group, the Oracle Investor Group, the
Company and its affiliates shall have entered into this Agreement.

            In consideration of the above recitals and the mutual covenants
contained herein, Watson, the Galen Investor Group, the Oracle Investor Group,
the Company and the Grantors and Guarantors hereby agree as follows:

                                  ARTICLE I

                                 DEFINITIONS

            SECTION 1.1.            DEFINITIONS OF CERTAIN TERMS.  As used
herein, the  following terms have the meanings set forth below:

                        "Agreement" is defined in the Preamble hereto.

                        "Business Day" shall mean any day other than a Saturday,
Sunday or other day on which commercial banks are authorized or required to be
closed in New York.

                        "Closing Date" means the date on which this Agreement
becomes effective in accordance with Section 14.10.

                        "Collateral" means all the properties and assets of
whatever nature, tangible or intangible, now owned or existing or hereafter
acquired or arising, of any of the Grantors on or in which the Secured Creditors
have been granted a lien or security interest pursuant to any of the Existing
Security Documents or Watson Security Documents or this Agreement.

                        "Event of Default" means any Event of Default under and
as defined in the Loan Agreement or Watson Security Documents.

                        "Existing Guaranty Agreements" means the guaranties and
agreements identified on Schedule 1 hereto.

                        "Existing Holders" is defined in the Recitals hereto.

                        "Existing Intercreditor Agreement" means that certain
Intercreditor Agreement, effective May 26, 1999, by and among Galen Partners
III, L.P., Galen Partners International III, L.P., Galen Employee Fund III,
L.P., and Oracle Strategic Partners, L.P.

                        "Existing Security Documents" means the guaranties,
mortgages, deeds of trust and security agreements identified on Schedule 1 and
Schedule 2 hereto.

                                       2
<PAGE>   6

                        "Grantors" means the Company, Halsey Pharmaceutical,
Inc., a Delaware corporation and Houba Inc., an Indiana corporation, and each
other subsidiary or affiliate of the Company that is or becomes a party to any
Security Document.

                        "Guarantors" means Halsey Pharmaceutical, Inc., a
Delaware corporation and Houba Inc., an Indiana corporation, and each other
person that is or becomes a party to any Guaranty Agreement.

                        "Loan" is defined in the Recitals hereto.

                        "Loan Agreement" is defined in the Recitals hereto.

                        "Note" means that certain Secured Promissory Note, dated
March __, 2000, executed by the Company in favor of Watson in the principal
amount of $17,500,000.

                        "Notice of Default" means a notice delivered by any
Secured Creditor stating that an Event of Default has been declared and setting
forth in reasonable detail the date and nature of such Event of Default.

                        "Secured Creditors" is defined in the Recitals hereto.

                        "Secured Obligations" is defined in the Recitals hereto.

                        "Senior Debt" means, at any time, the sum (without
duplication) of the following:

                        (i)     the aggregate principal amount of the Loan
outstanding at such time and the aggregate amount of accrued unpaid interest
thereon at such time; and

                        (ii)    the reasonable costs and expenses of
enforcement by Watson of its rights and collection with respect to the Loan.

                        "Subordinated Debt" means, at any time, the sum
(without duplication) of the following:

                        (i) the aggregate principal amount of the Existing
Debentures outstanding at such time and the aggregate amount of accrued unpaid
interest thereon at such time;

                        (ii) the aggregate amount of accrued and unpaid fees
payable to the Existing Holders, or any of them, under or in connection with the
Existing Debentures; and

                        (iii) the aggregate amount of all other monetary
obligations of the Company, the Guarantors and the Grantors that are accrued
and owing at such time to the Existing Holders, or any of them, under the
Existing Debentures (including all security, guaranty and other documents issued
or executed in connection with and on the same date as the Existing Debentures)
and the Existing Security Documents, including indemnification and expense
reimbursement obligations thereunder.

                        "Watson Security Documents" means the guaranties,
mortgages, deeds of trust and security agreements identified on Schedule 5.

        SECTION 1.2. TERMS GENERALLY. The definitions in Section 1.1 shall
apply equally to both the singular and plural forms of the terms defined.
Whenever the context may require, any pronoun

                                       3
<PAGE>   7


shall include the corresponding masculine, feminine and neuter forms. The words
"include," "includes" and "including" shall be deemed to be followed by the
phrase "without limitation." All references herein to Articles and Sections
shall be deemed references to Articles and Sections of this Agreement unless
the context shall otherwise require.

                                   ARTICLE II

                            STANDBY AND SUBORDINATION

        Except as set forth in Article 3 of this Agreement, the Existing
Holders shall not accept or receive, by setoff or in any other manner, as
against the Company or the Guarantors, the whole or any part of the Subordinated
Debt owing to the Existing Holders from the Company or the Guarantors, or any of
their respective predecessors, successors or assigns, including, without
limitation, a receiver, trustee or debtor in possession under the Existing
Debentures or any note, guaranty or other instrument or agreement executed by
the Company or the Guarantors in favor of the Existing Holders, or otherwise,
whether the sums represent principal, interest, costs, attorneys' fees or
charges, or other obligations due or not due, whether incurred directly or
indirectly, and whether absolute or contingent unless and until the Senior Debt
has been fully paid and satisfied.

                                  ARTICLE III

                                    PAYMENTS

        So long as no Event of Default shall have occurred and be continuing
under the Loan Agreement, the Company may pay to the Existing Holders, and the
Existing Holders may accept or receive regularly scheduled payments in respect
of the Subordinate Debt; provided, however, that the aggregate amount of
payments (in any form) which may be made to and accepted by the Existing Holders
shall not exceed the sum of Six Hundred and Twenty-Five Thousand Dollars
($625,000) on any Interest Payment Date (as such term is defined in the Existing
Debentures) and any arrearages thereon, and provided, further, however, that
certain holders of the Existing Debentures designated on Schedule 4 attached
hereto have agreed that, on each Interest Payment Date while any of the Senior
Debt is outstanding , such holders shall receive such payments in the capital
stock and/or like debenture instruments of Borrower and not in cash or cash
equivalents. Watson shall provide notice to Oracle Strategic Partners, L.P.,
Galen Partners III, L.P., Galen Employee Fund III, L.P., and Galen Partners
International III, L.P. of any Event of Default prior to its enforcement of its
remedies hereunder, provided however, that nothing herein shall impair Watson's
ability to act immediately after transmitting such notice. Except as to payments
which the Existing Holders are permitted to accept or receive pursuant to this
Article 3, the Existing Holders shall receive and hold all other payments or
distributions received prior to the satisfaction of the Senior Debt in trust for
the benefit of Watson and shall forthwith deliver the same to Watson in the same
form received (except for the endorsement or assignment in favor of Watson where
necessary) for application to the Senior Debt and, until so delivered, shall not
be commingled with other funds or property of the Existing Holders. Upon any
Event of Default under the Existing Debentures or the Support Documents, any
Existing Holder may file, prosecute and obtain a judgment in a lawsuit against
the Company or the Guarantors; provided, however, that the Existing Holders
shall not commence foreclosure on any judgment lien obtained in connection
therewith or otherwise exercise any remedy with respect thereto, including,
without limitation, filing any petition in bankruptcy with respect to the
Company or the Guarantors, unless and until all Senior Debt has been fully paid
and satisfied.


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                                   ARTICLE IV

                         SECURITY INTEREST SUBORDINATION

        All security interests acquired by Watson through the Watson Security
Documents, to the extent securing the Senior Debt, in the Collateral
shall at all times be prior and superior to any lien, ownership interest,
security interest or other interest or claim now held or hereafter acquired by
the Existing Holders in the Collateral (the "Subordinate Interest"). Said
priority shall be applicable irrespective of the time or order of attachment or
perfection of any security interest or the time or order of filing of any
financing statements or other documents, or any statutes, rules of law, or court
decisions to the contrary. Upon any disposition of any of the Collateral by
Watson, the Existing Holders agree, if requested by Watson, to execute and
immediately deliver any and all releases or other documents or agreements which
Watson deems necessary to accomplish a disposition thereof free of the
Subordinate Interest.

                                   ARTICLE V

                            DISPOSITION OF COLLATERAL

        The Existing Holders agree that, until Watson has received payment in
full of all Senior Debt, Watson may dispose of, and exercise any other rights
with respect to, any or all of the Collateral, free of the Subordinate Interest;
provided, that the Existing Holders retain any rights they may have as a junior
secured creditor with respect to the surplus, if any, arising from any such
disposition or enforcement. The Existing Holders agree that any funds of the
Company or the Guarantors which it obtains through the exercise of any right of
setoff or other similar right constitute Collateral, and the Existing Holders
shall immediately pay such funds to Watson to be applied to the outstanding
Senior Debt.

                                   ARTICLE VI

                                   SENIOR DEBT

        Until Watson has received payment in full of all Senior Debt, the
Existing Holders agree that, in addition to any other rights that Watson may
have, at law or in equity, Watson may at any time, and from time to time,
without the Existing Holders' consent and without notice to the Existing
Holders, renew or extend, but not increase, any of the Senior Debt or that of
any other person at any time directly or indirectly liable for the payment of
any Senior Debt, accept partial payments of the Senior Debt, settle, release (by
operation of law or otherwise), compound, compromise, collect or liquidate any
of the Senior Debt, change, alter or vary the interest charge on, or any other
terms or provisions of the Senior Debt or any present or future instrument,
document or agreement between the Senior Lender and the Company or the
Guarantors, and take any other action or omit to take any other action with
respect to the Senior Debt or the Collateral as Watson may deem necessary or
advisable in its sole discretion. The Existing Holders waive any right to
require Watson to marshal any assets in favor of the Existing Holders or against
or in payment of any or all of the Senior Debt. The Existing Holders further
waive any defense arising by reason of any claim or defense based upon an
election of remedies by Watson which in any manner impairs, affects, reduces,
releases, destroys and/or extinguishes any of the Existing Holders' subrogation
rights, rights to proceed against the Company or the Guarantors for
reimbursement, and/or any other rights of any of the Existing Holders.



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                                  ARTICLE VII

                                     DEFAULT

         The Existing Holders shall promptly give Watson written notice of any
Event of Default by the Company or the Guarantors on any obligation secured
by the Subordinate Interest.

                                  ARTICLE VIII

                                  NO COMMITMENT

        It is understood and agreed that this Agreement shall in no way be
construed as a commitment or agreement by Watson to continue financing
arrangements with the Company or the Guarantors.

                                   ARTICLE IX

                                   NO CONTEST

        The Existing Holders shall not contest the validity, perfection,
priority or enforceability of any lien or security interest granted to Watson to
secure the Senior Debt pursuant to the Watson Security Documents.

                                   ARTICLE X

                         FINANCIAL CONDITION OF BORROWER

        The Existing Holders are presently informed of the financial condition
of the Company and of all other circumstances which a diligent inquiry
would reveal and which bear upon the risk of non-payment of the Senior Debt and
the Subordinated Debt. The Existing Holders acknowledge that they are each
entitled to keep themselves informed under the terms of the Existing Debentures
and the Existing Security Documents as to the Company's financial condition and
all other circumstances which bear upon the risk of non-payment of the Senior
Debt and the Subordinated Debt or the Existing Holders' compliance with their
obligations hereunder. Except as otherwise specifically provided herein, the
Existing Holders waive any right to require Watson to disclose to them any
information which Watson may now or hereafter acquire concerning the Company or
the Guarantors.

                                   ARTICLE XI

                                     REVIVOR

        If any payment made on any of the Senior Debt shall for any reason be
required to be returned by Watson, whether on the ground that such payment
constituted a preference or for any other reason, then for purposes of this
Agreement, such payment on the Senior Debt shall be treated as not having been
made, and this Agreement shall in all respects be effective with respect to such
Senior Debt as though such payment had not been made.


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                                  ARTICLE XII

                         REPRESENTATIONS AND WARRANTIES

        SECTION 12.1. REPRESENTATIONS AND WARRANTIES OF THE EXISTING HOLDERS.
The Existing Holders represent and warrant that they have not heretofore
transferred or assigned the Subordinate Interest or any financing statement
naming any Grantor as debtor and any Existing Holder as secured party, and that
they will not do so without first delivering a copy of this Agreement to the
proposed transferee or assignee.

        SECTION 12.2. REPRESENTATIONS AND WARRANTIES OF EACH PARTY. Each party
hereto represents and warrants to the other parties hereto that (a) the
execution, delivery and performance of this Agreement (i) have been duly
authorized by all requisite corporate action on its part and (ii) will not
contravene any provision of its charter or by-laws or any order of any court or
other governmental authority having applicability to it or any applicable law,
and (b) this Agreement has been duly executed and delivered by it and
constitutes its legal, valid and binding obligation.

                                  ARTICLE XIII

                        EXISTING INTERCREDITOR AGREEMENT

            The parties hereto acknowledge the existence of the Existing
Intercreditor Agreement. Nothing herein shall be deemed to rescind any portion
of the Existing Intercreditor Agreement and such agreement shall remain in full
force except as modified by the terms of this Agreement.

                                  ARTICLE XIV

                                  MISCELLANEOUS

        SECTION 14.1. NO INDIVIDUAL ACTION. No Secured Creditor may require any
other Secured Creditor to take or refrain from taking any action
hereunder or under any of the Support Documents or with respect to any of the
Collateral except as and to the extent expressly set forth in this Agreement.

        SECTION 14.2. SUCCESSORS AND ASSIGNS. This Agreement shall be binding
on and inure to the benefit of each of the Secured Creditors and their
respective successors and permitted assigns; provided, however, that, except as
provided in the next sentence, no Existing Holder may assign its rights or
obligations hereunder. The rights and obligations of any Existing Holder under
this Agreement may be assigned, and the term "Existing Holder" as used in this
Agreement shall include, any assignee, transferee or successor of such Existing
Holder under the Existing Debentures by the execution of a Joinder Agreement by
such assignee, transferee or successor, and any such assignee, transferee or
successor shall thereupon become an Existing Holder under and a party to this
Agreement. This Agreement is not intended to confer any benefit on, or create
any obligation of any Secured Creditor to, the Company or any third party,
including the Guarantors and other Grantors.

        SECTION 14.3. NOTICES.  Notices and other communications provided for
herein or in any Watson Security Document shall be in writing and shall
be delivered by hand or overnight courier service, mailed or sent by telex or
telecopy, as follows:



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                        (a) if to any Existing Holder, to it as set forth
opposite its signature on the signature pages hereto;

                        (b) if to Watson, to 311 Bonnie Circle, Corona,
California, 91720, fax no. (909) 270-1096, to the attention of Mr. Robert
Funsten, General Counsel; and

                        (c) if to the Company, to 695 No. Perryville Road,
Rockford, Illinois 61107, fax no. (815) 399-9710, to the attention of Mr.
Michael Reicher, Chief Executive Officer any Grantor, or any Guarantor, to it as
specified in the Support Document to which it is a party.

                        (d) if to the other Grantors and Guarantors,
as applicable to: (i) Houba, Inc., 16235 State Road, #17, Culver, Indiana
46511, fax no: ____________, to the attention of Mr. Michael Reicher, Chief
Executive Officer; or (ii) Halsey Pharmaceutical, Inc., 695 No. Perryville
Road, Rockford, Illinois 61107, fax no. (815) 399-9710, to the attention of Mr.
Michael Reicher, Chief Executive Officer. All notices and other communications
given to any party hereto in accordance with the provisions of this Agreement
shall be deemed to have been given on the date of receipt if delivered by hand
or overnight courier service or sent by telex or telecopy, or on the date five
Business Days after dispatch by certified or registered mail if mailed, in each
case delivered, sent or mailed (properly addressed) to such party as provided
in this Section 14.3 or in accordance with the latest unrevoked direction from
such party given in accordance with this Section 14.3.

        SECTION 14.4. TERMINATION. This Agreement shall terminate automatically
upon the indefeasible payment in full of the Senior Debt.

        SECTION 14.5. APPLICABLE LAW.  THIS AGREEMENT SHALL BE CONSTRUED IN
ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF CALIFORNIA, WITHOUT
REFERENCE TO ITS CHOICE OF LAW RULES.

        SECTION 14.6. AMENDMENTS AND WAIVERS OF AGREEMENT AND SUPPORT DOCUMENTS.
No amendment or waiver of any provision of this Agreement or any Support
Document shall in any event be effective unless the same shall be in writing and
signed by the Secured Creditors; provided, however, that no such amendment or
waiver which materially affects the duties of the Company shall be effective
without the prior written consent of the Company. No waiver of any provision of
this Agreement and no consent to any departure by any party hereto from the
provisions hereof shall be effective unless such waiver or consent shall be set
forth in a written instrument executed by the party against which it is sought
to be enforced, and then such waiver or consent shall be effective only in the
specific instance and for the purpose for which given. No notice to or demand on
any party hereto in any case shall entitle such party to any other or further
notice or demand in the same, similar or other circumstances.


        SECTION 14.7. WAIVER OF RIGHTS. Neither any failure nor any delay on the
part of any party hereto in exercising any right, power or privilege
hereunder shall operate as a waiver thereof, and a single or partial exercise
thereof shall not preclude any other or further exercise or the exercise of any
other right, power or privilege.

        SECTION 14.8. SEVERABILITY. In case any one or more of the provisions
contained in this Agreement should be invalid, illegal or unenforceable
in any respect, the validity, legality and

                                       8
<PAGE>   12


enforceability of the remaining provisions contained herein shall not in
any way be affected or impaired thereby. The parties shall endeavor in good
faith negotiations to replace the invalid, illegal or unenforceable provisions
with valid provisions the economic effect of which comes as close as possible to
that of the invalid, illegal or unenforceable provision.

        SECTION 14.9. WAIVER OF JURY TRIAL. NEITHER THE COMPANY, THE SECURED
CREDITORS OR ANY GRANTOR OR GUARANTOR, NOR ANY ASSIGNEE, SUCCESSOR, HEIR
OR PERSONAL REPRESENTATIVE OF THE COMPANY, ANY SECURED CREDITOR, OR ANY GRANTOR
OR GUARANTOR SHALL SEEK A JURY TRIAL IN ANY LAWSUIT, PROCEEDING, COUNTERCLAIM OR
ANY OTHER LITIGATION PROCEDURE BASED UPON OR ARISING OUT OF OR OTHERWISE
RELATING TO THIS AGREEMENT, THE SUPPORT DOCUMENTS, ANY RELATED INSTRUMENT OR
AGREEMENT, ANY COLLATERAL FOR ALL OR ANY PART OF THE LOAN AGREEMENT OBLIGATIONS
OR EXISTING DEBENTURE OBLIGATIONS, OR THE DEALINGS OR THE RELATIONSHIP BETWEEN
OR AMONG SUCH PERSONS. THE COMPANY, EACH SECURED CREDITOR AND EACH GRANTOR AND
GUARANTOR HEREBY WAIVE ANY AND ALL RIGHT TO ANY SUCH JURY TRIAL. NEITHER THE
COMPANY, ANY SECURED CREDITOR NOR ANY GRANTOR OR GUARANTOR SHALL SEEK TO
CONSOLIDATE ANY SUCH ACTION IN WHICH A JURY TRIAL HAS BEEN WAIVED WITH ANY OTHER
ACTION IN WHICH A JURY TRIAL CANNOT OR HAS NOT BEEN WAIVED. THE PROVISIONS OF
THIS SECTION HAVE BEEN FULLY DISCUSSED BY THE PARTIES HERETO, AND THE PROVISIONS
OF THIS AGREEMENT SHALL BE SUBJECT TO NO EXCEPTIONS. NO PARTY HAS IN ANY WAY
AGREED WITH OR REPRESENTED TO ANY OTHER PARTY THAT THE PROVISIONS OF THIS
SECTION WILL NOT BE FULLY ENFORCED IN ALL INSTANCES.

        SECTION 14.10. COUNTERPARTS; EFFECTIVENESS. This Agreement may be
executed in two or more counterparts, each of which shall constitute an
original, but all of which, when taken together, shall constitute but one
instrument. This Agreement shall become effective on the date (the "Closing
Date") this Agreement shall have been executed and delivered by each party
identified in the introductory paragraph hereto.

        SECTION 14.11. SECTION HEADINGS. The Article and Section headings used
herein are for convenience of reference only and are not to affect the
construction of or be taken into consideration in interpreting this Agreement.

        SECTION 14.12. COMPLETE AGREEMENT. This Agreement constitutes the entire
agreement between the parties hereto with respect to the subject matter hereof
and supersedes all prior representations, negotiations, writings, memoranda and
agreements. To the extent any provision of this Agreement conflicts with any of
the documents referenced herein, the provisions of this Agreement shall be
controlling.

                           [signature pages to follow]


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        IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be duly executed by their duly authorized officers all as of the day and year
first above written.

<TABLE>
<CAPTION>

<S>                                                                            <C>

"WATSON"                                                                        "THE COMPANY"

WATSON PHARMACEUTICAL, INC.,                                                    HALSEY DRUG CO., INC.,
a Nevada corporation                                                            a New York corporation

/s/  Robert C. Funsten                                                          /s/ Michael Reicher
----------------------                                                          ----------------------
By:                                                                             By:
Its:  Senior Vice President                                                     Its:  Chief Executive Officer

"GRANTOR/GUARANTOR"                                                             "GRANTOR/GUARANTOR"

HOUBA, INC.,                                                                    HALSEY PHARMACEUTICAL, INC.,
an Indiana corporation                                                          a Delaware corporation

/s/ Michael Reicher                                                             /s/ Michael Reicher
----------------------                                                          ----------------------
By:                                                                             By:
Its:  Chief Executive Officer                                                   Its:  Chief Executive Officer

ORACLE STRATEGIC PARTNERS, L.P.                                                 GALEN PARTNERS III, L.P.
By: Oracle Strategic Capital L.L.C.,                                            By: Claudius, L.L.C., General Partner
 General Partner                                                                610 Fifth Avenue, 5th Fl.
712 Fifth Avenue                                                                New York, New York  10019
New York, New York  10019

/s/ Larry Feinberg                                                              /s/ Shrini Conjeevaram
----------------------                                                          ----------------------
By:                                                                             By:
Its:  Managing Member                                                           Its:  General Partner

GALEN EMPLOYEE FUND III, L.P.
By: Wesson Enterprises, Inc.                                                    GALEN PARTNERS INTERNATIONAL, III, L.P.
610 Fifth Avenue, 5th Floor                                                     By: Claudius, L.L.C., General Partner
New York, New York 10020                                                        610 Fifth Avenue, 5th Floor
                                                                                New York, New York  10020

/s/ Bruce F. Wesson                                                             /s/ Shrini Conjeevaram
----------------------                                                          ----------------------
By:                                                                             By:
Its:  General Partner                                                           Its:  General Partner

</TABLE>


                                       10
<PAGE>   14



<TABLE>
<CAPTION>

<S>                                                                            <C>

ALAN SMITH                                                                      PATRICK COYNE
21 Bedlow Avenue                                                                477 Margo Lane
Newport, Rhode Island  02840                                                    Berwyn, Pennsylvania  19312

/s/ Alan Smith                                                                  /s/ Patrick Coyne
----------------------------                                                    ----------------------------


MICHAEL WEISBROT                                                                SUSAN WEISBROT
1136 Rock Creek Road                                                            1136 Rock Creek Road
Gladwyne, Pennsylvania  19035                                                   Gladwyne, Pennsylvania  19035

/s/ Michael Weisbrot                                                            /s/ Susan Weisbrot
----------------------------                                                    ----------------------------


GREG WOOD                                                                       DENNIS ADAMS
c/o D.R. International                                                          120 Kynlyn Road
7474 No. Figueroa Street                                                        Radnor, Pennsylvania  19312
Los Angeles, California  90041

/s/ Greg Wood                                                                   /s/ Dennis Adams
----------------------------                                                    ----------------------------


BERNARD SELZ                                                                    ROBERT W. BAIRD & CO., INC., TTEE
c/o Furman Selz                                                                 FBO Michael K. Reicher IRA
230 Park Avenue                                                                 c/o Halsey Drug Co., Inc.
New York, New York  10069                                                       695 North Perryville Rd.
                                                                                Crimson Building #2
                                                                                Rockford, Ill.  61107

/s/ Bernard Selz                                                                /s/ Michael K. Reicher
----------------------------                                                    ----------------------------
                                                                                By:
                                                                                Its:  Trustee

MICHAEL REICHER                                                                 PETER CLEMENS
c/o Halsey Drug Co., Inc.                                                       c/o Halsey Drug Co., Inc.
695 North Perryville Rd.                                                        695 North Perryville Rd.
Crimson Building #2                                                             Crimson Building #2
Rockford, Ill.  61107                                                           Rockford, Ill.  61107

/s/ Michael K. Reicher                                                          /s/ Peter Clemens
----------------------------                                                    ----------------------------
</TABLE>



                                       11
<PAGE>   15




<TABLE>
<CAPTION>


<S>                                                                            <C>

CONNIE REICHER TRUST
c/o Halsey Drug Co., Inc.                                                       STEFANIE HEITMEYER
695 North Perryville Rd.                                                        c/o Halsey Drug Co., Inc.
Crimson Building #2                                                             695 North Perryville Rd.
Rockford, Ill.  61107                                                           Crimson Building #2
                                                                                Rockford, Ill.  61107

/s/ Connie Reicher                                                              /s/ Stefanie Heitmeyer
----------------------------                                                    ----------------------------
By:
Its:  Trustee

DAN HILL                                                                        HEMANT K. SHAH
6725 Lynch Avenue                                                               29 Chrissy Drive
Riverbank, California  95367                                                    Warren, New Jersey  07059

/s/ Dan Hill                                                                    /s/ Hemant K. Shah
----------------------------                                                    ----------------------------


VARSHA H. SHAH                                                                  VARSHA H. SHAH AS CUSTODIAN
29 Chrissy Drive                                                                FOR SUMEET H. SHAH
Warren, New Jersey  07059                                                       29 Chrissy Drive
                                                                                Warren, New Jersey  07059

/s/ Varshah H. Shah                                                             /s/ Varshah H. Shah
----------------------------                                                    ----------------------------
                                                                                By:
                                                                                Its:  Custodian

VARSHA H. SHAH AS CUSTODIAN                                                     ILENE RAINISCH
FOR SACHIN H. SHAH                                                              c/o Alvin Rainisch
29 Chrissy Drive                                                                315 Devon Place
Warren, New Jersey  07059                                                       Morganville, New Jersey  07751

/s/ Varshah H. Shah                                                             /s/ Ilene Rainisch
----------------------------                                                    ----------------------------
By:
Its:  Custodian

MICHAEL RAINISCH                                                                KENNETH GIMBEL
c/o Alvin Rainisch                                                              2455 Montgomery Avenue
315 Devon Place                                                                 Highland Park, Ill.  60035
Morganville, New Jersey  07751

/s/ Michael Rainisch                                                            /s/ Kenneth Gimbel
----------------------------                                                    ----------------------------
</TABLE>



                                       12
<PAGE>   16




<TABLE>
<CAPTION>

<S>                                                                            <C>
KENNETH GIMBEL, IRA ACCOUNT
FBO KENNETH GIMBEL
2455 Montgomery Avenue
Highland Park, Ill.  60035


----------------------------
By:
Its:

</TABLE>



                                       13
<PAGE>   17







                                   SCHEDULE 1

                      LIST OF EXISTING GUARANTY AGREEMENTS

1.      Continuing Unconditional Secured Guaranty by Houba, Inc. dated
        March 10, 1998.

2.      Continuing Unconditional Secured Guaranty by Halsey Pharmaceutical, Inc.
        dated March 10, 1998.

3.      Continuing Unconditional Secured Guaranty by Houba, Inc. dated May 26,
        1999.

4.      Continuing Unconditional Secured Guaranty by Halsey Pharmaceutical, Inc.
        dated May 26, 1999.



                                   SCHEDULE 1
<PAGE>   18








                                   SCHEDULE 2

                       LIST OF EXISTING SECURITY DOCUMENTS

1.      Company General Security Agreement, dated March 10, 1998, between
        Halsey Drug Co., Inc. and Galen Partners III, L.P., as agent.

2.      Guarantors General Security Agreement, dated March 10, 1998, by and
        among Cenci Powder Products, Inc., Halsey Pharmaceutical, Inc., H.R.
        Cenci Laboratories, Inc., Houba, Inc., Indiana Fine Chemicals, Inc.
        and Galen Partners III, L.P., as agent.

3.      Stock Pledge Agreement, dated March 10, 1998, between Halsey Drug Co.,
        Inc. and Galen Partners III, L.P., as agent.

4.      Company General Security Agreement, dated March 26, 1999, between
        Halsey Drug Co., Inc. and Oracle Strategic Partners, L.P., as agent.

5.      Guarantors General Security Agreement dated, May 26, 1999, by and among
        Houba, Inc., Halsey Pharmaceutical, Inc. and Oracle Strategic Partners,
        L.P., as agent.

6.      Stock Pledge Agreement, dated May 26, 1999, between Halsey Drug Co.,
        Inc. and Oracle Strategic Partners, L.P., as agent.




                                   SCEHDULE 2
<PAGE>   19







                                   SCHEDULE 3

                      EXISTING MORTGAGES AND DEEDS OF TRUST

1.      Real estate mortgage, dated May 10, 1998, between Houba, Inc. and Galen
        Partners III, L.P., as agent, covering the property located at 16235
        State Road 17, Culver, Indiana 46511.

2.      Real estate mortgage, dated May 26, 1999, between Houba, Inc. and
        Oracle Strategic Partners, L.P., as agent, covering the property
        located at 16235 State Road 17, Culver, Indiana 46511.




                                       SCHEDULE 3
<PAGE>   20








                                   SCHEDULE 4

                                EXISTING HOLDERS

GALEN DEBENTURES

<TABLE>
<CAPTION>

                                                              Principal Amount of              $1.50               $2.375
Name and Address of Purchaser                                 Debenture Purchased             Warrants            Warrants
-----------------------------                                 -------------------             --------            --------

<S>                                                          <C>                             <C>                 <C>
Galen Partners III, L.P.*                                     $          15,423,195            1,557,898            1,557,898
610 Fifth Avenue, 5th Floor
New York, New York 10020


Galen Partners International III, L.P.*                       $           1,709,167              172,643              172,643
610 Fifth Avenue, 5th Floor
New York, New York 10020


Galen Employee Fund III, L.P.*                                $              67,638                6,833                6,833
610 Fifth Avenue, 5th Floor
New York, New York 10020

Michael Reicher*                                              $             300,000               30,303               30,303
c/o Halsey Drug Co., Inc.
1827 Pacific Street
Brooklyn, New York 11233

Peter Clemens*                                                $             100,000               10,101               10,101
c/o Halsey Drug Co., Inc.
1827 Pacific Street
Brooklyn, New York 11233


Stefanie Heitmeyer                                            $              20,000                2,020                2,020
c/o Halsey Drug Co., Inc.
1827 Pacific Street
Brooklyn, New York 11233


Dan Hill                                                      $              10,000                1,010                1,010
c/o Halsey Drug Co., Inc.
1827 Pacific Street
Brooklyn, New York 11233


</TABLE>


<TABLE>
<CAPTION>


                                                                        Purchase
Name and Address of Purchaser                                            Price
-----------------------------                                      ------------------

<S>                                                           <C>

Galen Partners III, L.P.*                                     $       15,423,195
610 Fifth Avenue, 5th Floor
New York, New York 10020


Galen Partners International III, L.P.*                       $        1,709,167
610 Fifth Avenue, 5th Floor
New York, New York 10020


Galen Employee Fund III, L.P.*                                $           67,638
610 Fifth Avenue, 5th Floor
New York, New York 10020

Michael Reicher*                                              $          300,000
c/o Halsey Drug Co., Inc.
1827 Pacific Street
Brooklyn, New York 11233

Peter Clemens*                                                $          100,000
c/o Halsey Drug Co., Inc.
1827 Pacific Street
Brooklyn, New York 11233


Stefanie Heitmeyer                                            $           20,000
c/o Halsey Drug Co., Inc.
1827 Pacific Street
Brooklyn, New York 11233


Dan Hill                                                      $           10,000
c/o Halsey Drug Co., Inc.
1827 Pacific Street
Brooklyn, New York 11233


</TABLE>

*Agrees to receive interest in capital stock or like kind debentures.



                                   SCHEDULE 4
<PAGE>   21


<TABLE>
<CAPTION>

                                                              Principal Amount of              $1.50               $2.375
Name and Address of Purchaser                                 Debenture Purchased             Warrants            Warrants
-----------------------------                                 -------------------             --------            --------

<S>                                                          <C>                             <C>                 <C>
Alan Smith                                                    $              10,000                1,010                1,010
c/o Halsey Drug Co., Inc.
1827 Pacific Street
Brooklyn, New York 11233

Dennis Adams                                                  $           1,170,000              118,182              118,182
120 Kynlyn Road
Radnor, Pennsylvania 19087

Patrick Coyne                                                 $              50,000                5,051                5,051
477 Margo Lane
Berwyn, Pennsylvania 19312

Michael Weisbrot and Susan Weisbrot                           $             300,000               30,303               30,303
1136 Rock Creek Road
Gladwyne, Pennsylvania 19035

Greg Wood                                                     $             100,000               10,101               10,101
1263 East Calaveras Street
Altadena, California 91001

Hemant K. Shah and Varsha H. Shah                             $             950,000               95,960               95,960
29 Christy Drive
Warren, New Jersey 07059

Varsha H. Shah as Custodian for                               $              20,000                2,020                2,020
Sumeet H. Shah
29 Christy Drive
Warren, New Jersey 07059

Varsha H. Shah as Custodian for                               $              20,000                2,020                2,020
Sachin H. Shah
29 Christy Drive
Warren, New Jersey 07059

Bernard Selz                                                  $             400,000               40,404               40,404
121 East 73rd Street
New York, New York 10021

</TABLE>







<TABLE>
<CAPTION>


Name and Address of Purchaser                                      Purchase
                                                                    Price
-----------------------------                                 ------------------

<S>                                                          <C>
Alan Smith                                                    $           10,000
c/o Halsey Drug Co., Inc.
1827 Pacific Street
Brooklyn, New York 11233

Dennis Adams                                                  $        1,170,000
120 Kynlyn Road
Radnor, Pennsylvania 19087

Patrick Coyne                                                 $           50,000
477 Margo Lane
Berwyn, Pennsylvania 19312

Michael Weisbrot and Susan Weisbrot                           $          300,000
1136 Rock Creek Road
Gladwyne, Pennsylvania 19035

Greg Wood                                                     $          100,000
1263 East Calaveras Street
Altadena, California 91001

Hemant K. Shah and Varsha H. Shah                             $          950,000
29 Christy Drive
Warren, New Jersey 07059

Varsha H. Shah as Custodian for                               $           20,000
Sumeet H. Shah
29 Christy Drive
Warren, New Jersey 07059

Varsha H. Shah as Custodian for                               $           20,000
Sachin H. Shah
29 Christy Drive
Warren, New Jersey 07059

Bernard Selz                                                  $          400,000
121 East 73rd Street
New York, New York 10021



</TABLE>



*Agrees to receive interest in capital stock or like kind debentures.


                                  SCHEDULE 4

<PAGE>   22


<TABLE>
<CAPTION>

                                                              Principal Amount of              $1.50               $2.375
Name and Address of Purchaser                                 Debenture Purchased             Warrants            Warrants
-----------------------------                                 -------------------             --------            --------

<S>                                                          <C>                             <C>                 <C>
Ilene Rainisch                                                $              25,000                2,525                2,525
315 Devon Place
Morganville, New Jersey 07751

Michael Rainisch                                              $              25,000                2,525                2,525
48 Radford Street
Staten Island, New York 10314

Ken Gimbel                                                    $             100,000               10,101               10,101
876 Kimball Road
Highland Park, Illinois 60035


                                                                     Purchase
Name and Address of Purchaser                                          Price
-----------------------------                                    ------------------

<S>                                                           <C>
Ilene Rainisch                                                 $           25,000
315 Devon Place
Morganville, New Jersey 07751

Michael Rainisch                                               $           25,000
48 Radford Street
Staten Island, New York 10314

Ken Gimbel                                                     $          100,000
876 Kimball Road
Highland Park, Illinois 60035

</TABLE>



*Agrees to receive interest in capital stock or like kind debentures.


                                   SCHEDULE 4
<PAGE>   23



<TABLE>
<CAPTION>

                                                      Debenture Number
                                                      and Corresponding         $1.50               $2.375         Purchase
Name and Address of Purchaser                         Principal Amount         Warrants            Warrants          Price
-----------------------------                         ----------------         --------            --------        ---------
<S>                                                 <C>                       <C>                 <C>               <C>

Galen Partners III, L.P.*                              No. N-19A
610 Fifth Avenue, 5th Floor                            $681,105                  68,798              68,798          $    681,105
New York, New York 10020

Galen Partners International III, L.P.*                No. N-38
610 Fifth Avenue, 5th Floor                            $3,073,704               310,476             310,476          $  3,073,704
New York, New York 10020

Galen Employee Fund III,                               No. N-20
L.P.*                                                  $65,913                    6,658               6,658          $    65,913
610 Fifth Avenue, 5th Floor
New York, New York 10020                               No. N-39
                                                       $297,456                  30,044              30,044          $   297,456

                                                       No. N-21
                                                       $2,982                       301                 301          $     2,982

                                                       No. N-40
                                                       $13,456                    1,361               1,361          $    13,456


Michael Reicher*                                       No. N-22
c/o Halsey Drug Co., Inc.                              $50,000                    5,026               5,026          $    50,000
1827 Pacific Street
Brooklyn, New York 11233


Robert W. Baird & Co., Inc. TTEE,                      No. N-22A
FBO Michael K. Reicher IRA,                            $22,115                    2,258               2,258         $    22,115
Account Number 7026-6907
c/o Halsey Drug Co., Inc.
1827 Pacific Street
Brooklyn, New York 11233


Peter Clemens*                                          No. N-23
c/o Halsey Drug Co., Inc.                               $24,038                   2,428               2,428          $  24,038
1827 Pacific Street
Brooklyn, New York 11233


</TABLE>


*Agrees to receive interest in capital stock or like kind debentures.


                                   SCHEDULE 4


<PAGE>   24



<TABLE>
<CAPTION>


                                                Debenture Number
                                                and Corresponding               $1.50               $2.375             Purchase
Name and Address of Purchaser                   Principal Amount               Warrants            Warrants              Price
-----------------------------                   ----------------               --------            --------           -----------

<S>                                               <C>                       <C>                  <C>         <C>
Stefanie Heitmeyer                                 No. N-24
c/o Halsey Drug Co., Inc.                          $4,808                    486                  486         $            4,808
1827 Pacific Street
Brooklyn, New York 11233


Dan Hill                                           No. N-25
c/o Halsey Drug Co., Inc.                          $2,404                    243                  243         $            2,404
1827 Pacific Street
Brooklyn, New York 11233


Alan Smith                                         No. N-29
c/o Halsey Drug Co., Inc.                          $2,404                    243                  243         $            2,404
1827 Pacific Street
Brooklyn, New York 11233

Dennis Adams                                       No. N-31
120 Kynlyn Road                                    $281,250               28,409               28,409         $          281,250
Radnor, Pennsylvania 19087

Patrick Coyne                                      No. N-32
477 Margo Lane                                     $12,019                 1,214                1,214         $           12,019
Berwyn, Pennsylvania 19312

Michael Weisbrot and Susan Weisbrot                No. N-33
1136 Rock Creek Road                               $72,115                 7,284                7,284         $           72,115
Gladwyne, Pennsylvania 19035

Greg Wood
1263 East Calaveras Street                         No. N-26
Altadena, California 91001                         $24,038                 2,428                2,428         $           24,038

Hemant K. Shah and Varsha H. Shah                  No. N-34
29 Christy Drive                                   $228,365               23,067               23,067         $          228,365
Warren, New Jersey 07059

Varsha H. Shah as Custodian for Sumeet H. Shah     No. N-35
29 Christy Drive                                   $4,808                    486                  486         $            4,808
Warren, New Jersey 07059


*Agrees to receive interest in capital stock or like kind debentures.

</TABLE>

                                   SCHEDULE 4
<PAGE>   25

<TABLE>
<CAPTION>
                                                Debenture Number
                                                and Corresponding               $1.50               $2.375             Purchase
Name and Address of Purchaser                   Principal Amount               Warrants            Warrants              Price
-----------------------------                   ----------------               --------            --------           -----------

<S>                                                      <C>                    <C>                 <C>               <C>
Varsha H. Shah as Custodian for Sachin H. Shah            No. N-36
29 Christy Drive                                          $4,808                    486                486       $       4,808
Warren, New Jersey 07059


Bernard Selz                                              No. N-37
121 East 73rd Street                                      $96,154                 9,712              9,712              96,154
New York, New York 10021
                                                                                                                 $
Ilene Rainisch                                            No. N-27
315 Devon Place                                           $6,010                    607                607               6,010
Morganville, New Jersey 07751
                                                                                                                 $
Michael Rainisch                                          No. N-28
48 Radford Street                                         $6,010                    607                607               6,010
Staten Island, New York 10314

Ken Gimbel                                                 No. N-30
876 Kimball Road                                           $24,038                2,428              2,428       $        24,038
Highland Park, Illinois 60035



*Agrees to receive interest in capital stock or like kind debentures.


                                   SCHEDULE 4


</TABLE>


<PAGE>   26


                                EXISTING HOLDERS

ORACLE DEBENTURES

<TABLE>
<CAPTION>
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
                                                                    Principal
                   Oracle Debentures                           Amount of Debenture               $1.404                  $2.285
             Name and Address of Purchaser                          Purchased                   Warrants                Warrants
             -----------------------------                          ---------                   --------                --------
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
<S>                                                        <C>                               <C>                     <C>
1.    Oracle Strategic Partners, L.P.*                      $     5,000,000.00                  505,050                  505,050
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
2.    Oracle Strategic Partners, L.P.*                      $    5,000,000.00(1)              1,010,100                1,010,100
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
3.    Galen Partners III, L.P.*                             $    5,964,583.09(2)                602,483                  602,483
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
4.    Galen Partners International III, L.P.*               $      539,900.40(3)                 54,535                   54,535
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
5.    Galen Employee Fund III, L.P.*                        $       24,424.10(4)                  2,467                    2,467
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
6.    Patrick Coyne                                         $       51,178.08(5)                  5,169                    5,169
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
7.    Alan Smith                                            $       13,358.08(6)                  1,349                    1,349
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
8.    Michael and Susan Weisbrot                            $      564,446.96(7)                 57,015                   57,015
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
9.    Greg Wood                                             $      204,712.33(8)                 20,678                   20,678
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
10.   Dennis Adams                                          $       300,000.00                   30,303                   30,303
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
11.   Bernard Selz                                          $       200,000.00                   20,202                   20,202
--------------------------------------------------------- ------------------------------ ----------------------- -------------------
                        Total                               $    17,862,603.04             2,309,351.00             2,309,351.00
--------------------------------------------------------- ------------------------------ ----------------------- -------------------








                   Oracle Debentures
             Name and Address of Purchaser                           Purchase Price
             -----------------------------                           --------------
------------------------------------------------------------- -----------------------------
<S>                                                            <C>
1.    Oracle Strategic Partners, L.P.*                          $     5,000,000.00
------------------------------------------------------------- -----------------------------
2.    Oracle Strategic Partners, L.P.*                          $     5,000,000.00
------------------------------------------------------------- -----------------------------
3.    Galen Partners III, L.P.*                                 $     5,964,583.09
------------------------------------------------------------- -----------------------------
4.    Galen Partners International III, L.P.*                   $       539,900.40
------------------------------------------------------------- -----------------------------
5.    Galen Employee Fund III, L.P.*                            $        24,424.10
------------------------------------------------------------- -----------------------------
6.    Patrick Coyne                                             $        51,178.08
------------------------------------------------------------- -----------------------------
7.    Alan Smith                                                $        13,358.08
------------------------------------------------------------- -----------------------------
8.    Michael and Susan Weisbrot                                $       564,446.96
------------------------------------------------------------- -----------------------------
9.    Greg Wood                                                 $       204,712.33
------------------------------------------------------------- -----------------------------
10.   Dennis Adams                                              $       300,000.00
------------------------------------------------------------- -----------------------------
11.   Bernard Selz                                              $       200,000.00
------------------------------------------------------------- -----------------------------
                        Total                                   $    17,862,603.04
------------------------------------------------------------- -----------------------------

</TABLE>

--------------------

1     Intentionally omitted.

2     Consists of the surrender of convertible bridge notes in the principal
      amount of $5,590,917 plus accrued and unpaid interest of $373,666.09.

3     Consists of the surrender of convertible bridge notes in the principal
      amount of $506,077 plus accrued and unpaid interest of $33,823.40.

4     Consists of the surrender of convertible bridge notes in the principal
      amount of $22,894 plus accrued and unpaid interest of $1,530.10.

5     Consists of (i) the surrender of convertible bridge notes in the
      principal amount of $25,000 plus accrued and unpaid interest of $1,178.08
      and (ii) an additional investment of $25,000.

6     Consists of the surrender of convertible bridge notes in the principal
      amount of $13,000 plus accrued and unpaid interest of $358.08.

7     Consists of (i) the surrender of convertible bridge notes in the
      principal amount of $351,222 plus accrued and unpaid interest of
      $13,224.96 and (ii) an additional investment of $200,000.

8     Consists of (i) the surrender of convertible bridge notes in the
      principal amount of $100,000 plus accrued and unpaid interest of
      $4,712.33 and (ii) an additional investment of $100,000.




*Agrees to receive interest in capital stock or like kind debentures.


                                   SCHEDULE 4



<PAGE>   27








                                    EXHIBIT A

                                     FORM OF

                                JOINDER AGREEMENT

        Reference is made to that certain Subordination Agreement, dated as of
March __, 2000 (the "Subordination Agreement"), by and among Watson
Pharmaceuticals, Inc., a Nevada corporation, Halsey Drug Co., Inc., a New York
corporation ("Halsey"), Galen Partners III, L.P., as Agent of the holders of the
Galen Debentures, the Oracle Investor Group and the Grantors and Guarantors
listed on the signature pages thereof. All capitalized terms used but not
defined herein have the respective meanings ascribed thereto in the
Subordination Agreement. This agreement is a Joinder Agreement referred to in
Section 14.2 of the Subordination Agreement.

        The undersigned hereby agrees that it is a party to the Subordination
Agreement and is therefore bound by, and subject to, the terms of the
Subordination Agreement, and that it is an "Existing Holder" under, and as
defined, therein.

        The undersigned certifies that on or about the date hereof it is the
holder of the following obligations of the Company outstanding under the
Existing Debentures, as applicable.

                             [describe obligations]

        The address for notices to the undersigned pursuant to the
Subordination  Agreement is as follows:
                         [set forth address for notices]

                                Very truly yours,

                                [CREDITOR]

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



                                   EXHIBIT A
<PAGE>   28


                                   SCHEDULE 5

                            WATSON SECURITY DOCUMENTS

Watson Security Agreement

Watson Stock Pledge Agreement

Watson Guaranty

Watson Guarantors Security Agreement

Deed of Trust on Culver, Indiana Property

Deed of Trust Subordination


                                   EXHIBIT A