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                                                                    EXHIBIT 4.28

                          LEINER HEALTH PRODUCTS INC.
                             901 EAST 233RD STREET
                            CARSON, CALIFORNIA 90745



                                                               February 23, 2001


The Bank Of Nova Scotia,
 as the U.S. Agent
One Liberty Plaza
New York, New York 10006

The Bank of Nova Scotia,
 as the Canadian Agent
44 King Street West -- 14th Floor
Toronto, Ontario
Canada, M5H 1H1

Each of the Lenders party to the
 Credit Agreement referred to below



                           AMENDMENT TO WAIVER LETTER



Gentlemen and Ladies:

         We refer to (a) the Amended and Restated Credit Agreement, dated as of
May 15, 1998 (as further amended, supplemented, amended and restated or
otherwise modified prior to the date hereof, the "CREDIT AGREEMENT"), among
Leiner Health Products Inc., a Delaware corporation (the "U.S. BORROWER"), Vita
Health Products Inc., a Manitoba corporation (the "CANADIAN BORROWER", and
together with the U.S. Borrower, the "BORROWERS"), the various financial
institutions as are or may become parties thereto which extend a Commitment
under the U.S. Facility (collectively, the "U.S. LENDERS"), the various
financial institutions as are or may become parties thereto which extend a
Commitment under the Canadian Facility (collectively, the "CANADIAN LENDERS"),
and together with the U.S. Lenders, the "LENDERS"), The Bank of Nova Scotia
("SCOTIABANK") as agent for the U.S. Lenders under the U.S. Facility (in such
capacity, the "U.S. AGENT"), Scotiabank, as agent for the Canadian Lenders under
the Canadian Facility (in such capacity, the "CANADIAN AGENT", and together with
the U.S. Agent, collectively, the "AGENTS"), Merrill Lynch Capital Corporation,
as Documentation Agent, and Salomon Brothers Holding Company Inc., as
Syndication Agent, and (b) the Waiver Letter, dated February 13, 2001 (the
"WAIVER LETTER"), from the Borrowers to the Agents and the Lenders. Unless
otherwise defined in this amendment letter (this "AMENDMENT") or the context
otherwise requires, terms

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used in this Amendment have the meanings provided in the Credit Agreement or
the Waiver Letter, as applicable.

         The Borrowers hereby request that the Lenders amend the Waiver Letter
by inserting the following at the end of the first sentence in the second
paragraph of the Waiver Letter:

         " as well as any Default or Event of Default under clause (b) of
         Section 9.2.13 of the Credit Agreement (referred to as the "FEE
         DEFAULT") resulting from the payment to North Castle and/or its
         Affiliates on January 2, 2001 of a fee pursuant to the terms of the
         Management Services Agreement in the amount of $750,000 and the
         subsequent expense reimbursement in the amount of $35,000, and any
         Default or Event of Default under Section 9.1.7 of the Credit
         Agreement or under any other Loan Document (referred to collectively
         as the "COLLATERAL DEFAULTS") resulting from the failure of the
         Borrowers to deliver, or cause to be delivered, to the Agents any
         Guaranties, Pledge Agreements, Security Agreements and/or any other
         documents, certificates or instruments, or do any other act,
         required under such Section or under such Loan Documents with
         respect to the acquisition of additional Subsidiaries and additional
         personal property, in each case to the extent such Subsidiaries and
         personal property are set forth in the perfection certificate to be
         delivered to the Agents on February 16, 2001 pursuant to this Waiver
         Letter".

         The Lenders also hereby waive, for so long as the Waiver Letter is in
effect, any breach of the representation and warranty made by the Borrowers in
the Waiver Letter that no Default (other than those specifically referenced in
the Waiver Letter) had occurred and was continuing, insofar as such statement is
untrue with respect to the Fee Default and the Collateral Defaults.

         In consideration of this Amendment, the Borrowers agree that they shall
(a) on the date hereof, make, or cause to be made, a voluntary prepayment of the
outstanding Revolving Loans in an amount equal to $785,000 in accordance with
clause (a) of Section 5.1.1 of the Credit Agreement, to be applied PRO RATA
among outstanding U.S. Revolving Loans and outstanding Canadian Revolving Loans
(it being understood that no reduction in either the U.S. Revolving Loan
Commitment or the Canadian Revolving Loan Commitment shall result from such
prepayment), and (b) no later than February 28, 2001, deliver to the Agents all
documents and instruments necessary to comply with the provisions of Section
9.1.7 of the Credit Agreement and with each other Loan Document with respect to
the Collateral Defaults. Failure to comply with each of these covenants shall
constitute an immediate Event of Default.

         In order to induce the Lenders to enter into this Amendment, the
Borrowers hereby represent and warrant that, after giving effect to this
Amendment and the effectiveness of the Waiver Letter, all of the statements set
forth in Section 7.2.1 of the Credit Agreement are true and correct.

         This Amendment shall become effective upon the receipt by the U.S.
Agent of (i) executed counterparts hereof by the Borrowers and the Required
Lenders (ii) $785,000 to be


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applied as a prepayment of the Revolving Loans as set forth above and (iii)
an agreement in form and substance satisfactory to it executed and delivered
by an authorized officer of North Castle pursuant to which North Castle will
irrevocably commit to return (or cause to be returned) to the U.S. Borrower
by no later than March 30, 2001 the $750,000 management fee paid by the U.S.
Borrower on January 2, 2001 and the subsequent $35,000 expense reimbursement,
in each case referred to above. This Amendment may be executed by the parties
hereto in several counterparts, each of which shall be an original and all of
which shall constitute together but one and the same agreement. Delivery of
an executed counterpart of a signature page to this Amendment by facsimile
shall be effective as delivery of a manually executed counterpart of this
Amendment.

         THIS AMENDMENT SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH,
THE INTERNAL LAWS OF THE STATE OF NEW YORK. Except as expressly waived by this
Amendment, all of the terms and provisions of the Waiver Letter, the Credit
Agreement and the other Loan Documents shall remain in full force and effect.
This Amendment is a Loan Document executed pursuant to the Credit Agreement and
shall be construed and administered in accordance with all of the terms and
provisions of the Credit Agreement.


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         If you are in agreement with the foregoing terms, kindly execute this
Amendment in the space provided below and deliver to the Agents an executed
counterpart of this Amendment.



                                               Very truly yours,

                                               LEINER HEALTH PRODUCTS INC.


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



                                               VITA HEALTH PRODUCTS INC.


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


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AGREED TO AND ACCEPTED
AS OF THE DATE FIRST
ABOVE WRITTEN:

THE BANK OF NOVA SCOTIA,
as the U.S. Agent, the Canadian Agent
and a Lender


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




-------------------------------------
[NAME OF LENDER]


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

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