<PAGE>

                                                                    EXHIBIT 10.3
                                                                  WARRANT NO. __

________________________________________________________________________________
________________________________________________________________________________

THIS WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE HEREOF HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933.  NEITHER THIS WARRANT NOR SUCH
SECURITIES, NOR ANY INTEREST OR PARTICIPATION HEREIN OR THEREIN MAY BE SOLD,
ASSIGNED, PLEDGED OR OTHERWISE TRANSFERRED OR ENCUMBERED EXCEPT IN COMPLIANCE
WITH THE TERMS AND CONDITIONS HEREOF.

                         ****************************

                                FORM OF WARRANT

                                      to

                                   Purchase

                             __________ shares of

                                 COMMON STOCK

                              and ______________

                                   WARRANTS

                           to Purchase Common Stock

                                      of

                      ENDO PHARMACEUTICALS HOLDINGS INC.

                         ****************************

          This certifies that, for value received and in reliance upon, and
subject to, the representations contained in Article V hereof,
_____________________ (the "Holder") is entitled to purchase from Endo
Pharmaceuticals Holdings Inc., a Delaware corporation (the "Company"), during
the period specified in Section 1.1, at a purchase price of $1.20 per share and
warrant, taken together (the "Exercise Price"), _____________ fully paid and
non-assessable shares ("Warrant Shares") of the Company's Common Stock, par
value $.01 per share ("Common Stock") and ___________ warrants (the "Endo
Warrants") to purchase shares of Common Stock pursuant to the Warrant Agreement,
dated as of ___________, 2000, between the Company and _________, as warrant
agent (the "Endo Warrant Agreement"), upon and subject to the terms and
conditions set forth in this Warrant.  The Exercise Price and the number of
Warrant Shares and Endo Warrants purchasable upon exercise of this Warrant are
subject to adjustment from time to time as provided in Article II.

________________________________________________________________________________
________________________________________________________________________________
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                                   ARTICLE I

                             Exercise of Warrants

          1.1. Exercise Period.  This Warrant shall be immediately exercisable
               ---------------
in whole or in part until 5:00 p.m. local time in New York, New York on
September 25, 2001 (the "Expiration Date").

          1.2. Method of Exercise.  Subject to the provisions of Article III of
               ------------------
this Warrant, to exercise this Warrant in whole or in part, the Holder shall
deliver to the Company at the address specified in Section 6.9 hereof: (i) a
written notice, substantially in the form of the Exercise Notice appearing at
the end of this Warrant, of its election to exercise this Warrant, which notice
shall specify the number of Warrant Shares and Endo Warrants to be purchased,
(ii) a certified or official bank check payable to the order of the Company in
an amount equal to the aggregate current Exercise Price of the number of Warrant
Shares of Common Stock and number of Endo Warrants being purchased, as adjusted
as provided in Article II hereof, and (iii) this Warrant.  The Company shall as
promptly as practicable, and in any event within 20 days after receipt by the
Company of such notice, execute and deliver or cause to be executed and
delivered, in accordance with said notice, a certificate or certificates
representing the aggregate number of Warrant Shares and of Endo Warrants,
specified in such notice, issued in the name of the Holder.  Such certificate or
certificates shall be deemed to have been issued to the Holder, and the Holder
shall be deemed for all purposes to have become a holder of record of such
shares as of the date notice and payment is received by the Company.  If this
Warrant shall have been exercised only in part, the Company shall at the time of
delivery of said certificate or certificates deliver to the Holder a new Warrant
evidencing the right of the Holder to purchase the remaining Warrant Shares and
Endo Warrants, which new Warrant shall in all other respects be identical to
this Warrant or, at the request of the Holder, appropriate notation shall be
made on this Warrant and the same returned to the Holder.

          1.3. Warrant Shares Fully Paid.  All Warrant Shares issued upon the
               -------------------------
exercise of this Warrant shall be validly issued, fully paid and non-assessable.

                                  ARTICLE II

            Distributions, Reorganizations, Conversion and Mergers

          2.1. Stock Dividends, Recapitalizations, etc.  If, prior to the
               ---------------------------------------
expiration of this Warrant, there is any stock dividend on or stock split or
other reclassification of the outstanding shares of the Common Stock, or other
distribution thereon other than ordinary cash dividends payable out of earnings
                     -----
or surplus legally available for dividends, then the number of Warrant Shares
and Endo Warrants subject to this Warrant and the Exercise Price therefor shall
be appropriately adjusted to reflect such distribution, reclassification or
stock split.

          2.2. Mergers, Consolidations, etc.  If, prior to the expiration of
               ----------------------------
this Warrant, there is any consolidation, merger or sale of all or substantially
all of the assets of the Company, the Company shall use reasonable efforts to
make adequate provision so that the Holder shall thereafter be entitled to
purchase pursuant to this Warrant (in lieu of the number of Warrant
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Shares and Endo Warrants to which he would have been entitled at the time of
such consolidation, merger or sale) the shares of stock or other securities or
property to which such number of shares of Common Stock and the number of Endo
Warrants would have been entitled at that time, and at an aggregate purchase
price equal to the then applicable Exercise Price which would have been payable
in accordance with this Article II if such number of shares of Common Stock and
the number of Endo Warrants had been purchased by exercise of this Warrant
immediately prior to such consolidation, merger or sale.

          2.3. Exercisability of the Endo Warrants.  If, prior to the expiration
               -----------------------------------
of this Warrant, the Endo Warrants become exercisable pursuant to the Endo
Warrant Agreement, this Warrant will cease to be exercisable for Endo Warrants
after the Expiration Date (as defined and set forth in the Endo Warrant
Agreement).  This Warrant will thereafter be exercisable only for the number of
Warrant Shares for which it was exercisable prior to such date.

          2.4. Notifications by the Company.  If any time prior to the
               ----------------------------
expiration of this Warrant:

               (i)    the Company pays any dividend payable in stock upon the
     Common Stock or makes any distribution (other than ordinary cash dividends
     payable out of earnings or surplus legally available for dividends) to the
     holders of the Common Stock;

               (ii)   there is any capital reorganization, or reclassification
     of the capital stock of the Company, or consolidation or merger of the
     Company with, or sale of all or substantially all of its assets to, another
     corporation;

               (iii)  there is a voluntary or involuntary dissolution,
     liquidation or winding-up of the Company; or

               (iv)   the Endo Warrants shall have become exercisable pursuant
     to the Endo Warrant Agreement;

the Company shall give notice of such action to the Holder and, if applicable,
notice of the date on which the books of the Company shall close or a record
shall be taken for such dividend or distribution, the date on which such
reorganization, reclassification, consolidation, merger, sale, conversion,
dissolution, liquidation or winding-up shall take place or the date on which the
Endo Warrants became exercisable, as the case may be.  With respect to clauses
(i), (ii) and (iii) above, such notice shall also specify the date as of which
the holders of the Company's capital stock of record shall participate in such
dividend or distribution, or shall be entitled to exchange their capital stock
or securities or other property deliverable upon such reorganization,
reclassification, consolidation, merger, sale, conversion, dissolution,
liquidation or winding-up, as the case may be.  With respect to clauses (i),
(ii) and (iii) above, such notice shall be given not less than 20 days prior to
the action in question and not less than 10 days prior to the record date or the
date on which the Company's transfer books are closed in respect thereto.  With
respect to clause (iv) above, such notice shall be given not less than 15 days
after the date on which the Endo Warrants become exercisable pursuant to the
Endo Warrant Agreement.

                                       3
<PAGE>

          2.5. Successive Application.  The foregoing provisions of this Article
               ----------------------
II shall similarly apply to successive reclassifications, capital
reorganizations and changes of shares of the Company's capital stock, and to
successive consolidations, mergers and sales.

          2.6. Basis for Adjustments.  Any adjustment effected pursuant to this
               ---------------------
Article II shall be made on the basis of the number of Warrant Shares and number
of Endo Warrants which the Holder would have been entitled to acquire by
exercise of this Warrant immediately prior to the event giving rise to the
adjustment, and to the Exercise Price hereunder, per Warrant Share and Endo
Warrant, on the basis of the respective Exercise Price in effect immediately
prior to the event giving rise to the adjustment.  Promptly upon the occurrence
of each adjustment hereunder, the President of the Company shall give written
notice thereof to the Holder, which notice shall state the Exercise Price
resulting from such adjustment and the increase or decrease, if any, in the
number of Warrant Shares and number of Endo Warrants purchasable upon the
exercise of this Warrant, setting forth in reasonable detail the method of
calculation and the facts upon which such calculation is based.

                                  ARTICLE III

                     Restrictions on Exercise and Transfer

          3.1. Restrictions on Exercise and Transfer.  Notwithstanding any
               -------------------------------------
provisions contained in this Warrant to the contrary, this Warrant shall not be
exercisable or transferable and the related Warrant Shares and Endo Warrants
shall not be transferable except with either the prior written consent of the
Company or upon satisfaction of the conditions specified in Section 3.2, which
conditions are intended, among other things, to insure compliance with the
provisions of the Securities Act of 1933 (the "Act") in respect of the exercise
or transfer of this Warrant or transfer of the Warrant Shares and Endo Warrants.

          3.2. Conditions of Exercise and Transfer.  The Holder, by his
               -----------------------------------
acceptance hereof, agrees that he will not transfer or exercise this Warrant, or
transfer any Warrant Shares or Endo Warrants (a) either (i) prior to delivering
to the Company an opinion of counsel in form and substance reasonably
satisfactory to the Company, together with such other documentation that the
Company may reasonably request, to evidence that such exercise and/or transfer
does not require registration under the Act or violates any applicable state
securities law, or (ii) until registration of the related Warrant Shares and
Endo Warrants under the Act has become effective, and (b) prior to complying
with any applicable state securities laws.

          3.3. Non-Recognition of Prohibited Transfers.  Any transfer or attempt
               ---------------------------------------
to transfer this Warrant and/or any of the Warrant Shares or Endo Warrants
otherwise than in accordance with the terms and conditions of this Warrant
Agreement, or to a person younger than 18 years of age, shall be void and shall
not be binding upon the Company, and the purported transferee thereof shall not
be deemed to be the holder of such Warrants and/or Warrant Shares or Endo
Warrants, nor entitled to any of the rights of a holder thereof.  The Company
may refuse the transfer of any Warrant and/or Warrant Shares or Endo Warrants on
its books or records attempted to be made in violation of this Agreement.

                                       4
<PAGE>

                                  ARTICLE IV

                       Certain Covenants of the Company

          4.1. Reservation of Shares.  The Company covenants and agrees that it
               ---------------------
will reserve and set apart and have at all times, free from preemptive rights, a
number of shares of Common Stock and a number of Endo Warrants deliverable upon
the exercise of this Warrant sufficient to enable it at any time to fulfill its
obligations under this Warrant.

          4.2. Binding Effect.  This Warrant shall be binding upon any
               --------------
corporation succeeding to the Company by merger, consolidation or acquisition of
all or substantially all of the Company's assets.

                                   ARTICLE V

                    Investor Representations and Warranties

          The Holder hereby represents, warrants and covenants to the Company as
follows:

          5.1. Acquisition of this Warrant, and upon exercise of this Warrant,
purchase of the Warrant Shares and Endo Warrants is for the Holder's own
account, and not for distribution or resale to others.  The Holder acknowledges
that neither this Warrant nor the Warrant Shares or Endo Warrants have been or
will be registered under the Act, but are intended to be exempt from
registration under the Act and the rules promulgated thereunder.  In availing
itself of this exemption, the Company has relied on the representations of the
Holder contained herein.

          5.2. The Holder understands and agrees that this Warrant and the
Warrant Shares and Endo Warrants are restricted from transfer in accordance with
the provisions of Article III, and moreover cannot be offered, sold or otherwise
disposed of unless (a) (i) pursuant to an effective registration statement under
the Act, or (ii) pursuant to an opinion of counsel (in form and substance
reasonably satisfactory to the Company) and such other documentation that the
Company reasonably requests, evidencing that the proposed offer, sale or other
disposition is exempt from registration under the Act, and (b) all applicable
state securities laws have been complied with; and that the Company does not
intend to register this Warrant or the Warrant Shares or the Endo Warrants or to
take any other steps to enable the Holder to make an offer, sale or other
disposition of this Warrant or the Warrant Shares or the Endo Warrants under the
Act.

          5.3. Upon exercise of this Warrant, the Holder will be purchasing
Warrant Shares and Endo Warrants without being furnished any specific offering
literature or disclosure documents.  The Holder will be entitled to receive from
the Company such annual and quarterly reports containing financial statements
and a general description of the Company's activities as are provided by the
Company to the holders of the Common Stock.

          5.4. Other than information which has been and will be given to the
Holder as described in Section 5.3 above, no representations or warranties have
been made to the Holder by the Company, or any officer, director, employee or
agent of the Company.

                                       5
<PAGE>

          5.5. The Holder is an "Accredited Investor" within the meaning of Rule
501(a) under the Act or an entity in which all of  the equity owners are
accredited investors within the meaning of Rule 501(a)(1), (2) or (3) under the
Act.

          5.6. The Holder will rely solely upon the advice of his own tax and
legal advisors with respect to the tax and other legal aspects of an investment
in the Warrant Shares and Endo Warrants.

                                  ARTICLE VI

                                 Miscellaneous

          6.1. Entire Agreement.  This Warrant constitutes the entire agreement
               ----------------
between the parties hereto with respect to the subject matter hereof.

          6.2. Binding Effect; Benefits.  This Warrant shall inure to the
               ------------------------
benefit of and shall be binding upon the Company and the Holder and their
respective heirs, legal representatives, successors and permitted assigns.
Nothing in this warrant, expressed or implied, is intended to or shall confer on
any person other than the Company and the Holder, or their respective legal
representatives, successors or permitted assigns, any rights, remedies,
obligations or liabilities under or by reason of this Warrant.

          6.3. Amendments and Waivers.  This Warrant may not be modified or
               ----------------------
amended except by an instrument or instruments in writing signed by the party
against whom enforcement of any such modification or amendment is sought.
Either party hereto may, by an instrument in writing, waive compliance by the
other party with any term or provision of this Warrant on the part of such other
party hereto to be performed or complied with.  The waiver by any party hereto
of a breach of any term or provision of this Warrant shall not be construed as a
waiver of any subsequent breach.

          6.4. Assignment.  Neither this Warrant nor any rights, remedy,
               ----------
obligation or liability arising hereunder or by reason hereof shall be
assignable by the Holder, except in compliance with the provisions of Article
III.

          6.5. Section and other Headings.  The Article, Section and other
               --------------------------
headings contained in this Warrant are for reference purposes only and shall not
be deemed to be a part of this Warrant or to affect the meaning or
interpretation of this Warrant.

          6.6. Limitations of Liability; Not Stockholders.  No provision of this
               ------------------------------------------
Warrant shall be construed as conferring upon the Holder the right to vote,
consent, receive dividends or receive notice other than as expressly provided
herein in respect of meetings of stockholders for the election of directors of
the Company or any other matter whatsoever as a stockholder of the Company.  No
provision hereof, in the absence of affirmative action by the Holder to purchase
Warrant Shares and Endo Warrants, and no mere enumeration herein of the rights
or privileges of the Holder, shall give rise to any liability of the Holder for
the purchase price of any Warrant Shares or Endo Warrants or as a stockholder of
the Company, whether such liability is asserted by the Company or by creditors
of the Company.

                                       6
<PAGE>

          6.7. Loss, Destruction, Etc, of Warrants.  Upon receipt of evidence
               -----------------------------------
satisfactory to the Company of the loss, theft, mutilation or destruction of
this Warrant and, in the case of any such loss, theft or destruction upon
delivery of a bond of indemnity in such form and amount as shall be reasonably
satisfactory to the Company, or in the event of such mutilation upon surrender
and cancellation of the Warrant, the Company will make and deliver a new
Warrant, of like tenor, in lieu of such lost, stolen, destroyed or mutilated
Warrant.  Any Warrant issued under the provisions of this Section 6.7 in lieu of
any Warrant alleged to be lost, destroyed or stolen, or in lieu of any mutilated
Warrant, shall constitute an original contractual obligation on the part of the
Company.

          6.8. Law Governing.  This Warrant shall be governed by, and construed
               -------------
and enforced in accordance with, the laws of the State of New York without
regard to its conflicts of law principles.

          6.9. Notices.  All notices and other communications required or
               -------
permitted to be given under this Warrant shall be in writing and shall be deemed
to have been duly given if delivered personally or sent by United States mail,
postage prepaid, to the parties hereto at the following addresses or to such
other address as any party hereto shall hereafter specify by notice to the other
party hereto:

               (a)  if to the Company, addressed to:

                    Endo Pharmaceuticals Holdings Inc.
                    223 Wilmington-West Chester Pike
                    Chadds Ford, Pennsylvania 19317
                    Attention: Carol A. Ammon
                    Fax No.: (610) 558-9683

with a copy to:

                    Skadden, Arps, Slate, Meagher & Flom LLP
                    Four Times Square
                    New York, New York 10036
                    Attention:  Eileen T. Nugent
                    Fax No.: (212) 735-2000

               (b)  if to the Holder, addressed to:

                    [Name]
                    [Address]

Except as otherwise provided herein, all such notices and communications shall
be deemed to have been received when delivered personally, on the date of
delivery thereof, or when mailed, on the fifth business day after the mailing
thereof.

          6.10.Severability.  Any term or provision of this Warrant which is
               ------------
invalid or unenforceable in any jurisdiction shall, as to such jurisdiction, be
ineffective to the extent of such invalidity or unenforceability without
rendering invalid or unenforceable the remaining terms

                                       7
<PAGE>

and provisions of this Warrant or affecting the validity or enforceability of
any of the terms or provisions of this Warrant in any other jurisdiction.

          6.11. Fractional Shares.  No fractional shares or scrip representing
                -----------------
fractional shares shall be issued upon the exercise of this Warrant.  With
respect to any fraction of a share called for upon any exercise hereof, the
Company shall pay to the Warrant Holder an amount in cash equal to such fraction
multiplied by the then applicable Exercise Price as of the date of such
exercise.

          6.12. Counterparts.  This Warrant may be executed in any number of
                ------------
counterparts, each of which shall be deemed an original, but all of which
together constitute one and the same instrument.

          IN WITNESS WHEREOF, each of the parties hereto has signed, or caused
this Warrant to be signed by its duly authorized officer, as of ___________,
2000.

                             ENDO PHARMACEUTICALS HOLDINGS INC.

                             By:______________________________________
                                Title:

                             [Warrant Holder]

                             By:______________________________________
                                Title:

                                       8
<PAGE>

                                EXERCISE NOTICE
                                ---------------

                (To be executed upon exercise of this Warrant)

ENDO PHARMACEUTICALS HOLDINGS INC.

The undersigned hereby irrevocably elects to exercise the right, represented by
this Warrant, to purchase _______ shares of Common Stock and ___________ Endo
Warrants covered by this Warrant and herewith tenders payment for such Warrant
Shares and Endo Warrants by certified or official bank check payable to the
order of ENDO PHARMACEUTICALS HOLDINGS INC. in the amount of $___________ in
accordance with the terms of this Warrant.  The undersigned requests that (a) a
certificate for such Warrant Shares and Endo Warrants be registered in the name
of ___________________ /*/ and that such certificates be delivered to
___________________________ __________________________ whose address is
______________________________________ and (b) if such shares do not include all
of the shares issuable as provided in this Warrant, that a new Warrant of like
tenor and date for the balance of the Warrant Shares and Endo Warrants issuable
hereunder be delivered to ___________ __________________________.*



Date _______________          Signature _______________________________

                              Social Security Number __________________

                              Address _________________________________

____________

/*/  Either the Holder or a transferee approved in accordance with Article III
of this Warrant.

                                       9