<PAGE>

                                                                    EXHIBIT 4.25

                             SUPPLEMENTAL INDENTURE

         This SUPPLEMENTAL INDENTURE (this "Supplemental Indenture"), dated as
of August 9, 2001, is made by and among PharMerica, Inc., a Delaware corporation
(the "Company"), the Subsidiary Guarantors (the "Subsidiary Guarantors") to the
Indenture (as defined below) as identified on Schedule A thereof and BNY Midwest
Trust Company (as successor to Harris Trust and Savings Bank), as trustee under
the Indenture (the "Trustee").

                               W I T N E S S E T H

         WHEREAS, the Company and the Subsidiary Guarantors have heretofore
executed and delivered to the Trustee a certain indenture (the "Indenture"),
dated as of March 31, 1998, providing for the issuance of an aggregate principal
amount of $325,000,000 of 8 3/8% Senior Subordinated Notes due 2008 (the
"Notes");

         WHEREAS, on July 17, 2001, the Company commenced an offer to purchase
all of the outstanding Notes and a consent solicitation to adopt certain
amendments to the Indenture (the "Proposed Amendments"), on the terms and
subject to the conditions set forth in that certain Offer to Purchase and
Consent Solicitation Statement, dated July 17, 2001, as may have been, and may
be further, modified and amended by the Company from time to time (the
"Statement");

         WHEREAS, pursuant to Section 9.02 of the Indenture, the consent of the
holders (each a "Holder" and collectively, the "Holders") of a majority in
principal amount of the Notes outstanding is required to adopt the Proposed
Amendments (the "Majority Threshold"), other than the Asset Sale Amendment, as
that term is defined in the Statement, and the consent of the Holders of at
least two-thirds in principal amount of the Notes then outstanding is required
to adopt the Asset Sale Amendment (the "Two-Thirds Threshold");

         WHEREAS, pursuant to Sections 9.02 and 9.06 of the Indenture, the
Trustee is obligated to execute this Supplemental Indenture upon request of the
Company, accompanied by a board resolution authorizing the execution hereof,
evidence of the aforesaid requisite consents, and the Trustee's receipt of an
Officer's Certificate and Opinion of Counsel (as those terms are defined in the
Indenture) stating that the execution hereof is authorized or permitted by the
Indenture (collectively, the "Trustee Conditions");

         WHEREAS, in response to the Consent Solicitation (as that term is
defined in the Statement), the Company has received consents from Holders
meeting the Majority Threshold;

         WHEREAS, pursuant to Sections 9.02 and 9.06 of the Indenture, the
Trustee is authorized to execute this Supplemental Indenture;

<PAGE>

         NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, each of the
Company, the Subsidiary Guarantors and the Trustee mutually covenant and agree
for the equal and ratable benefit of the Holders of the Notes as follows:

         Section 1. Capitalized Terms. Capitalized terms used herein without
definition shall have the meanings assigned to them in the Indenture.

         Section 2. Conditions Precedent. Each of the Trustee Conditions has
been satisfied in all respects. The Company, the Subsidiary Guarantors and the
Trustee are this date executing and thereupon making effective this Supplemental
Indenture.

         Section 3. Amendments to the Indenture. Pursuant to Section 9.02 of the
Indenture, at the opening of business on the Acceptance Date (as that term is
defined in the Statement), the Indenture shall be amended by: (1) deleting
Sections 4.03, 4.04, 4.05, 4.07, 4.08, 4.09, 4.11, 4.12, 4.13, 4.15, 4.16, 4.17,
4.18, 4.19, 5.01, and 6.01(d) through and including 6.01(h) of the Indenture;
(2) replacing each such Section with the words "Intentionally omitted."; (3)
deleting all textual references in the Indenture and the Notes to each such
Section; and (4) deleting all definitions in the Indenture and the Notes
exclusively related to each such Section; including without limitation, the
following:

         (a)  Section 1.01 of the Indenture is hereby amended as follows:

                  (1) The second parenthetical phrase in clause (i) of the
definition of "Asset Sale" shall be deleted in its entirety; and

                  (2) By deleting the following definitions in their entirety,

                        "Acquired Debt",
                        "Attributable Debt",
                        "Consolidated Cash Flow",
                        "Consolidated Interest Expense",
                        "Consolidated Net Income",
                        "Consolidated Net Worth",
                        "Existing Indebtedness"
                        "Fixed Charges",
                        "Fixed Charge Coverage Ratio",
                        "Incur",
                        "Marketable Securities",
                        "Net Income",
                        "Permitted Investment",
                        "Permitted Liens",
                        "Permitted Refinancing Indebtedness",
                        "Restricted Investment", and
                        "Subordinated Indebtedness".

                                       -2-

<PAGE>

         (c) Section 6.01(c) of the Indenture is hereby amended by deleting the
words "Sections 4.10, 4.14 or 5.01" and replacing them with "Sections 4.10 and
4.14".

         (d) Section 6.02 of the Indenture is hereby amended by deleting all
text contained in said Section but the first and last sentence thereof.

         (e) All references to the Sections of the Indenture deleted by Section
3 of this Supplemental Indenture shall be deleted from Section 8.03 of the
Indenture.

         (f) Section 8.04(e) of the Indenture shall be amended by deleting the
words "or insofar as Sections 6.01(g) or 6.01(h) hereof is concerned, at any
time in the period ending on the 91st day after the date of deposit" appearing
therein.

         (g) Section 11.03 of the Indenture is hereby amended by deleting: (1)
the first proviso in the first sentence thereof; and (2) the words "(i) in the
event of an Asset Sale, the Net Proceeds from such sale or other disposition are
applied in accordance with the provisions of Section 4.10 hereof and (ii)"
appearing in the second sentence thereof.

         Section 4. Further Amendments to the Indenture. If at or prior to the
Expiration Date (as that term is defined in the Statement) consents from Holders
meeting the Two-Thirds Threshold shall have been obtained, then at the opening
of business on the Acceptance Date, pursuant to Section 9.02 of the Indenture,
the Indenture shall be further amended by: (1) deleting Section 4.10 of the
Indenture; (2) replacing such Section with the words "Intentionally omitted.";
(3) deleting all textual references in the Indenture to such Section; and (4)
deleting all definitions exclusively related thereto; including without
limitation, the following:

         (a) Section 1.01 of the Indenture shall be further amended by deleting
the following definitions in their entirety:

                "Asset Sale";
                "Designated Noncash Consideration"`;
                "Equity Interests";
                "Investments";
                "Net Income";
                "Net Proceeds";
                "Non-Recourse Debt";
                "Permitted Joint Venture"; and
                "Related Business".

         (b) Section 3.01 of the Indenture is hereby amended by deleting the
words "4.10 or" appearing in the first sentence of the second paragraph thereof.

         (c) Section 3.05 of the Indenture is hereby amended by:

                                       -3-

<PAGE>

              (1) deleting the words "4.10 or" appearing in the first sentence
         of the first paragraph thereof.

              (2) deleting the words "an Asset Sale Offer or" each time they
         appear in the first sentence of the second paragraph thereof, and
         replacing them with the word "a".

         (d) Section 3.08 of the Indenture is hereby amended by deleting the
words ", 4.10 and" appearing therein.

         (e) Section 3.09 of the Indenture is hereby amended by: (1) deleting
the words "pursuant to an Asset Sale Offer under Section 4.10 hereof" appearing
in the first paragraph thereof; (2) deleting the words "or an Asset Sale Offer
shall be required to be made pursuant to Section 4.10, as the case may be,"
appearing in the first sentence of the second paragraph thereof; (3) replacing
the words "Section 4.10 hereof, in the case of an Asset Sale Offer, or 4.14
hereof, in the case of a Change of Control Offer" with the words "4.14 hereof";
(4) deleting the words "or Asset Sale Offer, as the case may be," appearing in
the fourth sentence of the fourth paragraph thereof; and (5) replacing the words
"Section 4.10 or 4.14 hereof, as the case may be," appearing in clause (a) of
the fourth paragraph thereof with the words "4.14 hereof".

         (f) Section 6.01(b) of the Indenture is hereby further amended by
deleting the words "or an Asset Sale Offer" appearing therein.

         (g) Section 6.01(c) of the Indenture is hereby further amended by
deleting the words "Sections 4.10 and 4.14" appearing therein and replacing them
with the words "Section 4.14".

         Section 5. Corresponding Amendments to the Notes. Each Note shall be
amended to make the terms of such Note consistent with the terms of the
Indenture, as amended by this Supplemental Indenture. To the extent of any
conflict between the terms of the Notes and the terms of the Indenture, as
amended by this Supplemental Indenture, the terms of the Indenture, as amended
by this Supplemental Indenture, shall control.

         Section 6. Notice to Trustee. Within 30 days after the Acceptance Date,
the Company shall give the Trustee written notice indicating the Acceptance Date
and stating that consents from holders meeting the Two-Thirds Threshold shall
have been received; provided, however, the failure of the Company to give such
notice shall in no way impair the validity or the operation of any provision in
this Supplemental Indenture.

         Section 7. New York Law to Govern. The internal law of the State of New
York shall govern and be used to construe this Supplemental Indenture.

                                       -4-

<PAGE>

         Section 8. Counterparts. The parties may sign any number of copies of
this Supplemental Indenture. Each signed copy shall be an original, but all of
them together represent the same agreement.

         Section 9. Effect Of Headings. The Section headings herein are for
convenience only and shall not affect the construction hereof.

         Section 10. The Trustee. The Trustee shall not be responsible in any
manner whatsoever for or in respect of the validity or sufficiency of this
Supplemental Indenture or for or in respect of the correctness of the recitals
of fact contained herein, all of which recitals are made solely by the Company
and the Subsidiary Guarantors.

         Section 11. Conflicts. To the extent of any inconsistency between the
terms of this Supplemental Indenture and the Indenture, the terms of this
Supplemental Indenture shall control.

         Section 12. Entire Agreement. This Supplemental Indenture constitutes
the entire agreement of the parties hereto with respect to the amendments to the
Indenture set forth herein.

                            [Signature Pages Follows]

                                       -5-

<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed and attested, all as of the date first above
written.

                                        PHARMERICA, INC.

                                        SUBSIDIARY GUARANTORS:

                                        ALLIANCE HEALTH SERVICES, INC.
                                        BEVERLY ACQUISITION CORPORATION
                                        COMPUTRAN SYSTEMS, INC.
                                        DUNNINGTON DRUG, INC.
                                        HEALTHCARE PRESCRIPTION SERVICES,
                                         INC.
                                        INSTA-CARE HOLDINGS, INC.
                                        MEDICAL HEALTH INDUSTRIES INC.
                                        ALLIANCE HOME HEALTH CARE, INC.
                                        BROWNSTONE PHARMACY, INC.
                                        OMNI MED B, INC.
                                        DUNNINGTON RX SERVICES OF
                                         MASSACHUSETTS, INC.
                                        DUNNINGTON RX SERVICES OF RHODE
                                         ISLAND, INC.
                                        DD WHOLESALE, INC.
                                        PHARMACY CORPORATION OF AMERICA -
                                        MASSACHUSETTS, INC.
                                        INSTA-CARE PHARMACY SERVICES
                                         CORPORATION
                                        PHARMACY DYNAMICS GROUP, INC.
                                        PHARMACY CORPORATION OF    AMERICA
                                        CAPSTONE MED., INC.
                                        MEDIDYNE CORP.
                                        PHARMERICA DRUG SYSTEMS, INC.
                                        ROMBRO'S DRUG CENTER, INC.
                                        COMPUSCRIPT, INC.
                                        CAPSTONE PHARMACY OF DELAWARE, INC.
                                        PREMIER PHARMACY, INC.
                                        GOOT'S GOODIES, INC.
                                        SOUTHWEST PHARMACIES, INC.
                                        FAMILY CENTER PHARMACY, INC.
                                        TMESYS, INC.

                       [signatures continued on next page]

                                       -6-

<PAGE>

                                        EXPRESS PHARMACY SERVICES, INC.
                                        GOOT WESTBRIDGE PHARMACY, INC.
                                        GOOT NURSING HOME PHARMACY, INC.
                                        GOOT'S PHARMACY & ORTHOPEDIC
                                        SUPPLY, INC.

                                        By: /s/ Charles J. Carpenter
                                            ---------------------------------
                                        Name:  Charles J. Carpenter
                                        Title: President

                                        By:  /s/ Neil F. Dimick
                                             --------------------------------
                                        Name:  Neil F. Dimick
                                        Title: Executive Vice President and
                                               Chief Financial Officer

                                      TRUSTEE:

                                      BNY MIDWEST TRUST COMPANY

                                        By:    /s/ DGDonovan
                                               ------------------------------
                                        Name:  DGDonovan
                                        Title: Assistant Vice President

                            [Supplemental Indenture]

                                       -7-