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                                                                     Exhibit 4.2

                         COMMON STOCK PURCHASE AGREEMENT

         This Common Stock Purchase Agreement (the "Agreement") is made as of
January 15, 2004 between Questcor Pharmaceuticals, Inc., a California
corporation (the "Company"), and the purchasers who are signatories hereto (the
"Purchasers").

                                    AGREEMENT

         1.       Purchase and Sale of Common Stock.

                  1.1.     Sale to the Purchasers. Subject to the terms and
conditions hereof, the Company will issue and sell to each Purchaser the number
of shares (the "Shares") of Common Stock of the Company, no par value per share
(the "Common Stock"), set forth opposite such Purchaser's name on the signature
page hereto at a purchase price of $0.644 per Share (the "Purchase Price"). The
obligations of each Purchaser hereunder are several and not joint and no
Purchaser shall be obligated to purchase any Shares in excess of the number set
forth opposite such Purchaser's name on the signature page hereto.

                  1.2. Payment of Purchase Price. On or prior to the date hereof
(the "Closing Date"), the Purchase Price shall be payable by the Purchasers by
delivery to the Company of (i) the cash consideration ("Cash Consideration")
indicated on the signature page hereto plus (ii) the value of the warrants to be
surrendered to the Company for cancellation as indicated on the signature page
hereto (the "Warrant Valuation"), together as payment of the Purchase Price for
the Shares purchased by such Purchaser hereunder.

         2.       Closing Date and Delivery.

                  2.1.     Closing Date. The closing of the purchase and sale of
the Shares hereunder (the "Closing") will be held on the Closing Date and shall
occur at the offices of the Company, 3260 Whipple Road, Union City, CA 94587.

                  2.2.     Deliveries at Closing. At the Closing, the Company
shall deliver to each Purchaser a stock certificate registered in such
Purchaser's name, or in such nominee name(s) as designated by the Purchaser in
writing, representing the Shares purchased by such Purchaser. At the Closing,
each Purchaser shall (i) effect a wire transfer to the Company in the amount of
the Cash Consideration and (ii) surrender the warrants set forth opposite such
Purchaser's name on the signature page hereto to the Company for cancellation,
each as provided in Section 1.2.

         3.       Representations and Warranties by the Company. The Company
represents and warrants to each Purchaser as of the Closing Date that, except as
set forth in the SEC Reports (as hereinafter defined):

                  3.1.     Organization and Standing. The Company is a
corporation duly organized, validly existing and in good standing under the laws
of the State of California, and has the requisite corporate power and authority
to own, lease and operate its properties and to carry on its business as now
being conducted. The Company is qualified to do business and is in good standing
as a foreign corporation in every jurisdiction in which the failure to so
qualify would have a material adverse effect on the financial condition or
business of the Company.

                  3.2.     Changes. Except as set forth in the SEC Reports,
since September 30, 2003, the Company has not, to the extent material to the
Company: (a) incurred any debts, obligations or liabilities, absolute, accrued
or contingent, whether due or to become due, other than in the ordinary course
of business; (b) mortgaged, pledged or subjected to lien, charge, security
interest or other encumbrance any of its assets, tangible or intangible, other
than in the ordinary course of business; (c) waived any debt owed to the Company
or its subsidiaries, other than in the ordinary course of business; (d)
satisfied or discharged any lien, claim or encumbrance or paid any obligation
other than in the ordinary course of business; (e) declared or paid any
dividends, other than in the ordinary course of business; or (f) entered into
any transaction other than in the ordinary course of business.

                  3.3.     Litigation. Except as set forth in the SEC Reports,
there are no legal actions, suits, arbitrations or other legal, administrative
or governmental proceedings pending or, to the Company's knowledge, threatened
against the Company or its properties, assets or business, and the Company is
not aware of any facts which might result in or form the basis for any such
action,

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suit or other proceeding, in each case which, if adversely determined, would
individually or in the aggregate have a material adverse effect on the financial
condition or business of the Company.

                  3.4.     Compliance with Other Instruments. Except for such
matters which, either individually or in the aggregate, would not have a
material adverse effect on the financial condition or business of the Company,
the execution and delivery of, and the performance and compliance with, this
Agreement and the transactions contemplated hereby, with or without the giving
of notice or passage of time, will not (a) result in any breach of, or
constitute a default under, or result in the imposition of any lien or
encumbrance upon any asset or property of the Company pursuant to any agreement
or other instrument to which the Company is a party or by which it or any of its
properties, assets or rights is bound or affected; (b) violate the Amended and
Restated Articles of Incorporation (the "Articles") or Amended and Restated
Bylaws (the "Bylaws") of the Company, or any law, rule, regulation, judgment,
order or decree; or (c) except for the registration of the Shares under the
Securities Act of 1933, as amended (the "Securities Act"), the listing of the
Shares on the AMEX and such consents, approvals, authorizations, registrations
or qualifications as may be required under the Securities Exchange Act of 1934,
as amended (the "Exchange Act") and applicable state securities laws in
connection with the purchase of the Shares by the Purchasers, require any
consent, approval, authorization or order of or filing with any court or
governmental agency or body. The Company is not in violation of its Articles or
Bylaws nor in violation of, or in default under, any lien, mortgage, lease,
agreement or instrument, except for such defaults which would not, individually
or in the aggregate, have a material adverse effect on the financial condition
or business of the Company. The Company is not subject to any restriction which
would prohibit the Company from entering into or performing its obligations
under this Agreement, except for such restrictions which would not, individually
or in the aggregate, have a material adverse effect on the ability of the
Company to perform its obligations under this Agreement.

                  3.5.     Reports and Financial Statements. As of their
respective filing dates, the Company's Form 10-K for the year ended December 31,
2002, the Company's Proxy Statement in connection with the 2003 Annual Meeting
of Shareholders and all Forms 10-Q and 8-K filed by the Company with the
Securities and Exchange Commission (the "SEC") after January 1, 2003, in each
case without exhibits thereto (the "SEC Reports") were prepared in all material
respects in accordance with the requirements of the Securities Act or the
Exchange Act, as the case may be, and the rules and regulations of the SEC
thereunder applicable to such SEC Reports. The SEC Reports, when read as a
whole, do not contain any untrue statements of a material fact and do not omit
to state a material fact necessary to make the statements therein, in light of
the circumstances under which they were made, not misleading. The audited
consolidated financial statements and unaudited interim financial statements of
the Company included in the SEC Reports have been prepared in accordance with
United States generally accepted accounting principles applied on a consistent
basis (except as may be indicated therein or in the notes thereto) and fairly
present, in all material respects, the financial position of the Company as at
the dates thereof and the results of its operations and cash flows for the
periods then ended subject, in the case of the unaudited interim financial
statements, to normal year-end adjustments and any other adjustments described
in such financial statements.

                  3.6.     Securities. The Shares are duly and validly
authorized, issued and outstanding, fully paid, nonassessable and free and clear
of all pledges, liens, encumbrances and restrictions (other than arising under
federal or state securities laws). The issuance of the Shares is not subject to
any preemptive or other similar rights.

                  3.7.     Capital Stock. As of December 17, 2003, 45,355,828
shares of the Common Stock were issued and outstanding, 2,155,715 shares of the
Company's Series A Preferred Stock, no par value per share (the "Series A
Preferred Stock"), which are convertible into 2,155,715 shares of Common Stock,
were issued and outstanding, 9,100 shares of the Company's Series B Preferred
Stock, no par value per share (the "Series B Preferred Stock"), which are
convertible into 9,668,506 shares of Common Stock, were issued and outstanding,
2,531,646 shares of Common Stock issuable upon conversion of convertible
debentures, and options and/or warrants to purchase 18,058,076 shares of Common
Stock, were issued and outstanding. All of the outstanding shares of the
Company's capital stock are validly issued, fully paid and nonassessable. Except
as set forth in this Section 3.7, as of December 17, 2003, there are no
outstanding subscriptions, options, warrants, calls, contracts, demands,
commitments, conversion rights or other agreements or arrangements of any
character or nature whatever under which the Company is or may be obligated to
issue its Common Stock, Series A Preferred Stock, Series B Preferred Stock, or
warrants or options to purchase the Common Stock or the Series A Preferred Stock
or Series B Preferred Stock. No holder of any security of the Company is
entitled to any preemptive or similar rights to purchase any securities of the
Company.

                  3.8.     Corporate Acts and Proceedings. This Agreement has
been duly authorized by the requisite corporate action and has been duly
executed and delivered by an authorized officer of the Company, and is a valid
and binding obligation of the Company, enforceable in accordance with its terms,
except as such enforceability may be limited by bankruptcy, insolvency,
moratorium, reorganization or other similar laws affecting the enforcement of
creditors' rights generally and as to limitations on the

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enforcement of the remedy of specific performance and other equitable remedies.
The requisite corporate action necessary for the authorization, reservation,
issuance and delivery of the Shares has been taken by the Company.

                  3.9.     No Implied Representations. All of the Company's
representations and warranties are contained in this Agreement, and no other
representations or warranties by the Company shall be implied.

                  3.10.    Filing of Reports. Since the Company's Annual Report
on Form 10-K for the fiscal year ended December 31, 2002, the Company has filed
with the SEC all reports and other material required to be filed by it therewith
pursuant to Section 13, 14 or 15(d) of the Exchange Act and the Company is
eligible to register the offer and resale of the Shares by the holders thereof
on a Registration Statement on Form S-3.

                  3.11.    Compliance with Laws. The business and operations of
the Company have been conducted in accordance with all applicable laws, rules
and regulations of all governmental authorities, except for such violations
which would not, individually or in the aggregate, have a material adverse
effect on the financial condition or business of the Company.

                  3.12.    Proprietary Rights. To the knowledge of the Company,
the Company owns or is licensed to use all patents, patent applications,
inventions, trademarks, trade names, applications for registration of
trademarks, service marks, service mark applications, copyrights, trade secrets,
licenses and rights in any thereof and any other intangible property and assets
(herein called the "Proprietary Rights") which are material to the business of
the Company. Except as would not have a material adverse effect on the financial
condition or business of the Company, the Company does not have any knowledge
of, and the Company has not given or received any notice of, any pending
conflicts with or infringement of the rights of others with respect to any
Proprietary Rights. Except as would not have a material adverse effect on the
financial condition or business of the Company, no action, suit, arbitration, or
legal, administrative or other proceeding, or investigation is pending or, to
the knowledge of the Company, threatened, which involves any Proprietary Rights.
Except as would not have a material adverse effect on the financial condition or
business of the Company, to the knowledge of the Company, no Proprietary Rights
used by the Company, and no services or products sold by the Company, conflict
with or infringe upon any proprietary rights owned or licensed by any third
party. Except as would not have a material adverse effect on the financial
condition or business of the Company, no claims have been asserted by any person
with respect to the validity of the Company's ownership or right to use the
Proprietary Rights and, to the knowledge of the Company, there is no reasonable
basis for any such claim to be successful.

                  3.13.    Compliance with Environmental Laws. Except as would
not, singly or in the aggregate, have a material adverse effect on the financial
condition or business of the Company, the Company is not in violation of any
applicable statute, law or regulation relating to the environment or
occupational health and safety, and to the Company's knowledge, no expenditures
material to the Company are or will be required to comply with any such existing
statute, law or regulation. To the Company's knowledge, the Company does not
have any liability to any governmental authority or other third party arising
under or as a result of any such past or existing statute, law or regulation,
which liability would be material to the Company.

                  3.14.    Permits, Licenses, Etc. The Company owns, possesses
or has obtained, and is operating in compliance with, all governmental and
administrative licenses, permits, certificates, registrations, approvals,
consents and other authorizations (collectively, "Permits") necessary to own or
lease (as the case may be) and operate its properties, whether tangible or
intangible, and to conduct its businesses or operations as currently conducted,
except such licenses, permits, certificates, registrations, approvals, consents
and authorizations the failure of which to obtain would not have a material
adverse effect on the financial condition or business of the Company. The
Company has not received any notice of proceedings relating to the revocation,
modification or suspension of any Permits or any circumstance which would lead
it to believe that such proceedings are reasonably likely.

                  3.15.    Insurance. The Company maintains insurance of the
type and in the amount which the Company believes is reasonably adequate for its
business, including, but not limited to, insurance covering all real and
personal property owned or leased by the Company against theft, damage,
destruction, acts of vandalism and all other risks customarily insured against
by similarly situated companies, all of which insurance is in full force and
effect.

                  3.16.    Brokers or Finders. No agent, broker, investment
banker or other person (as such term is defined in the Securities Act) is or
will be entitled to any broker's or finder's fee or any other commission or
similar fee from the Company in connection with any of the transactions
contemplated hereby.

         4.       Representations and Warranties by the Purchasers; Restrictions
on Transfer. Each Purchaser severally represents and warrants to, and covenants
and agrees with, the Company, as of the Closing Date, as follows:

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                  4.1.     Authorization. Purchaser has all requisite legal and
corporate or other power and capacity and has taken all requisite corporate or
other action to execute and deliver this Agreement, to purchase the Shares to be
purchased by it and to carry out and perform all of its obligations under this
Agreement. This Agreement constitutes the legal, valid and binding obligation of
Purchaser, enforceable in accordance with its terms, except as such
enforceability may be limited by bankruptcy, insolvency, moratorium,
reorganization or other similar laws affecting the enforcement of creditors'
rights generally and as to limitations on the enforcement of the remedy of
specific performance and other equitable remedies.

                  4.2.     Investor Status. Purchaser is an "Accredited
Investor" as defined in Rule 501 of the Securities Act or a "Qualified
Institutional Buyer," as such term is defined in Rule 144A of the Securities
Act. Purchaser is aware of the Company's business affairs and financial
condition and has had access to and has acquired sufficient information about
the Company to reach an informed and knowledgeable decision to acquire the
Shares. Purchaser has such business and financial experience as is required to
give it the capacity to protect its own interests in connection with the
purchase of the Shares and is able to bear the risks of an investment in the
Shares. Purchaser is not itself a "broker" or a "dealer" as defined in the
Exchange Act and is not an "affiliate" of the Company as defined in Rule 405 of
the Securities Act.

                  4.3.     Investment Intent. Purchaser is purchasing the Shares
for its own account as principal, for investment purposes only, and not with a
present view to or for resale, distribution or fractionalization thereof, in
whole or in part, within the meaning of the Securities Act. Purchaser
understands that its acquisition of the Shares has not been registered under the
Securities Act or registered or qualified under any state securities law in
reliance on specific exemptions therefrom, which exemptions may depend upon,
among other things, the bona fide nature of Purchaser's investment intent as
expressed herein. Purchaser has, in connection with its decision to purchase the
Shares set forth in this Agreement, relied solely upon the representations and
warranties of the Company contained herein. Purchaser will not, directly or
indirectly, offer, sell, pledge, transfer or otherwise dispose of (or solicit
any offers to buy, purchase or otherwise acquire or take a pledge of) any of the
Shares, except in compliance with the Securities Act and the rules and
regulations promulgated thereunder and all applicable state securities laws.

                  4.4.     Registration or Exemption Requirements. Purchaser
further acknowledges and understands that the Shares may not be resold or
otherwise transferred except in a transaction registered under the Securities
Act and applicable state securities laws unless counsel to the Company shall
advise the Company that such transfer may be effected without such registration.
Purchaser understands that until the Shares have been registered under the
Securities Act and all applicable state securities laws, the certificates
evidencing the Shares will be imprinted with a legend that prohibits the
transfer of the Shares.

                  4.5.     Restriction on Sales, Short Sales and Hedging
Transactions. Purchaser represents and agrees that during the period from the
date Purchaser was first contacted with respect to the potential purchase of the
Shares through the date of the execution of this Agreement by Purchaser,
Purchaser did not, directly or indirectly, execute or effect or cause to be
executed or effected any short sale, option or equity swap transaction in or
with respect to the Common Stock or any other derivative security transaction
the purpose or effect of which is to hedge or transfer to a third party all or
any part of the risk of loss associated with the ownership of the Shares by the
Purchaser.

                  4.6.     No Legal, Tax Or Investment Advice. Purchaser
understands that nothing in this Agreement or any other materials presented to
Purchaser in connection with the purchase and sale of the Shares constitutes
legal, tax or investment advice. Purchaser has consulted such legal, tax and
investment advisors as it, in its sole discretion, has deemed necessary or
appropriate in connection with its purchase of the Shares.

                  4.7.     Brokers or Finders. Upon the consummation of the
transactions contemplated by this Agreement, no agent, broker, investment banker
or other Person is or will be entitled to any broker's or finder's fee or any
other commission or similar fee from the Purchaser in connection with any of the
transactions contemplated hereby.

         5.       Covenants.

                  5.1.     Registration Requirements.

                           (a) Promptly after, but not later than 5 days after,
the Company files its Annual Report on Form 10-K for the fiscal year ending
December 31, 2003 with the SEC (the "Filing Date"), the Company shall prepare
and file a registration statement (the "Registration Statement") with the SEC to
register the offer and resale of the Shares (the "Registrable Securities") by
the Purchasers and shall use commercially reasonable efforts to cause such
Registration Statement to become effective within 30 days

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from the Filing Date or not more than five days from the date upon which the SEC
shall allow the Company to accelerate effectiveness, whichever is shorter. In
the event that the Company shall fail to file the Registration Statement on or
prior to the Filing Date or shall fail to obtain effectiveness of the
Registration Statement within the 30-day period following the Filing Date (the
"Effectiveness Date"), then the Company will make pro rata payments to each
Purchaser (the "Liquidated Damages Payments"), as liquidated damages and not as
a penalty, in an amount equal to 1.0% of the aggregate amount of the Cash
Consideration paid by such Purchaser for each 30-day period or pro rata for any
portion therefore following the date by which such Registration Statement should
have been effective; provided, however, that if the Registration Statement is
subject to review by the SEC staff, then the Effectiveness Date shall be
extended by an additional 90 days without any Liquidated Damages Payments
required to be made; provided, further, the Company shall not be obligated to
make any Liquidated Damages Payments if the Registration Statement is not
effective due to the Purchaser's failure to provide any information about itself
that is necessary to be contained in such Registration Statement.

                           (b) The Company shall pay all Registration Expenses
(as defined below) in connection with any registration, qualification or
compliance hereunder and each Purchaser shall pay all Selling Expenses (as
defined below) and other expenses that are not Registration Expenses relating to
the Registrable Securities resold by such Purchaser. "Registration Expenses"
shall mean all expenses, except for Selling Expenses, incurred by the Company in
complying with the registration provisions herein described, including, without
limitation, all registration, qualification and filing fees, printing expenses,
escrow fees, fees and disbursements of counsel for the Company, blue sky fees
and expenses and the expense of any special audits incident to or required by
any such registration. "Selling Expenses" shall mean all selling commissions,
underwriting fees and stock transfer taxes applicable to the Registrable
Securities and all fees and disbursements of counsel for any Purchaser.

                           (c) If the Registration Statement becomes effective,
the Company will use commercially reasonable efforts to: (i) keep such
registration effective until the second anniversary of the date such
Registration Statement is declared effective; (ii) except as provided in Section
5.1(f), prepare and file with the SEC such amendments and supplements to the
Registration Statement and the prospectus used in connection with the
Registration Statement as may be necessary to comply with the provisions of the
Securities Act with respect to the disposition of all securities covered by the
Registration Statement; (iii) furnish such number of prospectuses and other
documents incident thereto, including any amendment of or supplement to the
prospectus, as a Purchaser from time to time may reasonably request; (iv) cause
the Shares to be listed on the AMEX or any securities exchange or quoted on each
quotation service on which the Common Stock of the Company is then listed or
quoted; (v) provide a transfer agent and registrar for all securities registered
pursuant to the Registration Statement and a CUSIP number for all such
securities; and (vi) file the documents required of the Company and otherwise
use commercially reasonable efforts to maintain requisite blue sky clearance in
all U.S. jurisdictions in which any of the Shares are originally sold and all
other states specified in writing by a Purchaser, provided, however, that the
Company shall not be required to qualify to do business in any state in which it
is not now so qualified or has not so consented.

                           (d) The Company shall furnish to each Purchaser upon
request a reasonable number of copies of a supplement to or an amendment of the
prospectus used in connection with the Registration Statement as may be
necessary to facilitate the public sale or other disposition of all or any of
the Registrable Securities held by Purchaser.

                           (e) With a view to making available to Purchasers the
benefits of Rule 144 of the Securities Act and any other rule or regulation of
the SEC that may at any time permit Purchasers to sell Registrable Securities to
the public without registration, the Company covenants and agrees to use
commercially reasonable efforts to: (i) make and keep public information
available as those terms are understood and defined in Rule 144 of the
Securities Act until the earlier of (A) the date on which the Registrable
Securities may be sold pursuant to Rule 144(k) (or any successor rule) or (B)
such date as all of the Registrable Securities shall have been resold; (ii) file
with the SEC in a timely manner all reports and other documents required of the
Company under the Securities Act and Exchange Act; and (iii) furnish to any
Purchaser upon request, as long as the Purchaser owns any Registrable
Securities, (A) a written statement by the Company that it has complied with the
reporting requirements of the Securities Act and the Exchange Act, (B) a copy of
the most recent annual or quarterly report of the Company, and (C) such other
information as may be reasonably requested in order to avail any Purchaser of
any rule or regulation of the SEC that permits the selling of any such
Registrable Securities without registration.

                           (f) Purchaser hereby acknowledges that there may be
times when the Company must suspend the use of the prospectus forming a part of
the Registration Statement until such time as an amendment to such Registration
Statement has been filed by the Company and declared effective by the SEC or
until the Company has amended or supplemented such prospectus. The Purchaser
hereby covenants that it will not sell any securities pursuant to said
prospectus during the period commencing at the time at which the Company gives
the Purchaser written notice of the suspension of the use of said prospectus and
ending at the time the Company gives the Purchaser written notice that Purchaser
may thereafter effect sales pursuant to said prospectus. Notwithstanding

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anything herein to the contrary, the Company shall not suspend use of the
Registration Statement by Purchaser unless such suspension is required by the
federal securities laws and the rules and regulations promulgated thereunder.

                           (g) As to any particular Registrable Securities, such
securities shall cease to be Registrable Securities when: (i) a registration
statement covering such securities shall have become effective under the
Securities Act and such securities have been disposed of in accordance with such
registration statement; (ii) such securities may be sold pursuant to Rule 144(k)
(or any successor rule); or (iii) such securities shall have ceased to be
outstanding.

                           (h) No Purchaser shall be entitled to any right
provided for in this Section 5.1 after the earlier of (i) five (5) years
following the effective date of the Registration Statement or (ii) the date on
which the Registrable Securities may be sold pursuant to Rule 144(k) (or any
successor rule).

                  5.2.     Indemnification and Contribution.

                           (a) The Company agrees to indemnify and hold harmless
each Purchaser from and against any losses, claims, damages or liabilities (or
actions or proceedings in respect thereof) to which such Purchaser may become
subject (under the Securities Act or otherwise) insofar as such losses, claims,
damages or liabilities (or actions or proceedings in respect thereof) arise out
of, or are based upon (i) any untrue statement or alleged untrue statement of a
material fact or omission or alleged omission to state a material fact in the
Registration Statement, on the effective date thereof, or any amendment or
supplements thereto; or (ii) any violation by the Company of any Federal, state
or common law rule or regulation applicable to the Company in connection with
any such registration, and the Company will, as incurred, reimburse such
Purchaser for any legal or other expenses reasonably incurred in investigating,
defending or preparing to defend, settling, compromising or paying any such
action, proceeding or claim; provided, however, that the Company shall not be
liable in any such case to the extent that such loss, claim, damage or liability
arises out of, or is based upon (i) an untrue statement or alleged untrue
statement of a material fact or omission or alleged omission in any registration
statement or prospectus in reliance upon and in conformity with written
information furnished to the Company by or on behalf of such Purchaser
specifically for use in preparation thereof; (ii) any untrue statement or
alleged untrue statement of a material fact contained in any registration
statement or prospectus delivered by the Purchaser after the Company had
notified the Purchaser in writing that such registration statement or prospectus
contained such untrue statement or alleged untrue statement; (iii) any omission
or alleged omission to state therein a material fact required to be stated
therein or necessary to make the statements therein not misleading after the
Company had notified the Purchaser in writing that such registration statement
or prospectus contained such omission or alleged omission; or (iv) the failure
of the Purchaser to deliver any preliminary or final prospectus, or any
amendments or supplements thereto, required under applicable securities laws,
including the Securities Act, to be so delivered, provided that a sufficient
number of copies thereof had been previously provided by the Company to the
Purchaser.

                           (b) Each Purchaser, severally and not jointly, agrees
to indemnify and hold harmless the Company from and against any losses, claims,
damages or liabilities (or actions or proceedings in respect thereof) to which
the Company may become subject (under the Securities Act or otherwise) insofar
as such losses, claims, damages or liabilities (or actions or proceedings in
respect thereof) arise out of, or are based upon (i) any untrue statement or
alleged untrue statement of a material fact or omission or alleged omission to
state a material fact in the Registration Statement, or any amendment or
supplements thereto, in reliance upon and in conformity with written information
furnished to the Company by or on behalf of such Purchaser specifically for use
in preparation of the Registration Statement or (ii) an untrue statement or
alleged untrue statement or omission or alleged omission in any prospectus that
is corrected in any subsequent prospectus or supplement or amendment thereto,
that was delivered to a Purchaser at least one (1) day prior to the pertinent
sale or sales by such Purchaser and not delivered by such Purchaser to the
entity to which it made such sale(s) prior to such sale(s), and each Purchaser,
severally and not jointly, will, as incurred, reimburse the Company for any
legal or other expenses reasonably incurred in investigating, defending or
preparing to defend any such action, proceeding or claim.

                           (c) Promptly after receipt by any indemnified person
of a notice of a claim or the beginning of any action in respect of which
indemnity is to be sought against an indemnifying person pursuant to this
Section 5.2, such indemnified person shall notify the indemnifying person in
writing of such claim or of the commencement of such action and, subject to the
provisions hereinafter stated, in case any such action shall be brought against
an indemnified person, the indemnifying person shall be entitled to participate
therein, and, to the extent that it shall wish, to assume the defense thereof,
with counsel reasonably satisfactory to the indemnified person. After notice
from the indemnifying person to such indemnified person of the indemnifying
person's election to assume the defense thereof, the indemnifying person shall
not be liable to such indemnified person for any legal expenses subsequently
incurred by such indemnified person in connection with the defense thereof;
provided, however, that if there exists or shall exist a conflict of interest
that would make it inappropriate in the opinion of outside counsel of the
indemnified person for the same counsel to represent both the indemnified person
and such indemnifying person or any affiliate or associate thereof, the

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indemnified person shall be entitled to retain its own counsel at the expense of
such indemnifying person; provided, further, that the indemnifying person shall
not be obligated to assume the expenses of more than one counsel to represent
all indemnified persons. No indemnifying person shall be liable for any
settlement of any action or proceeding effected without its written consent. No
indemnifying person shall, without the consent of the indemnified person (which
consent shall not be reasonably withheld or delayed), consent to entry of any
judgment or enter into any settlement which does not include as an unconditional
term thereof the giving by the claimant or plaintiff to such indemnified person
of a release from all liability in respect to such claim or litigation.

                           (d) If the indemnification provided for in this
Section 5.2 is unavailable to or insufficient to hold harmless an indemnified
person under subsection (a) or (b) above in respect of any losses, claims,
damages or liabilities (or actions or proceedings in respect thereof) referred
to therein, then each indemnifying person shall contribute to the amount paid or
payable by such indemnified person as a result of such losses, claims, damages
or liabilities (or actions in respect thereof) in such proportion as is
appropriate to reflect the relative fault of the Company on the one hand and
each Purchaser on the other in connection with the statements or omissions which
resulted in such losses, claims, damages or liabilities (or actions in respect
thereof), as well as any other relevant equitable considerations. The relative
fault shall be determined by reference to, among other things, whether the
untrue or alleged untrue statement of a material fact or the omission or alleged
omission to state a material fact relates to information supplied by the Company
on the one hand or a Purchaser on the other. The Company and the Purchasers
agree that it would not be just and equitable if contribution pursuant to this
subsection (d) were determined by pro rata allocation (even if the Purchasers
were treated as one entity for such purpose) or by any other method of
allocation which does not take into account the equitable considerations
referred to above in this subsection (d). The amount paid or payable by an
indemnified person as a result of the losses, claims, damages or liabilities (or
actions in respect thereof) referred to above in this subsection (d) shall be
deemed to include any legal or other expenses reasonably incurred by such
indemnified person in connection with investigating or defending any such action
or claim. No person guilty of fraudulent misrepresentation (within the meaning
of Section 11(f) of the Securities Act) shall be entitled to contribution from
any person who was not guilty of such fraudulent misrepresentation. The
Purchaser's obligations in this subsection (d) to contribute are several in
proportion to their sales of Shares, as the case may be, to which such loss
relates and not joint.

                           (e) The obligations of the Company and the Purchasers
under this Section 5.2 shall be in addition to any liability which the Company
and the respective Purchasers may otherwise have and the indemnification
obligations hereunder shall extend, as applicable, upon the same terms and
conditions, to directors, officers, employees and agents of the Company and the
Purchasers and to each person, if any, who controls the Company or any Purchaser
within the meaning of the Securities Act and the Exchange Act.

                  5.3      AMEX Listing. Promptly following the Closing Date,
the Company shall use its commercially reasonable efforts to cause the Shares to
be listed on the AMEX. So long as the Purchasers beneficially own any Shares,
the Company will use its commercially reasonable efforts to maintain the listing
of the Common Stock on the AMEX or a registered national securities exchange.

                  5.4      Short Sales. Until the Registration Statement becomes
effective pursuant to Section 5.1, each Purchaser shall not execute or effect or
cause to be executed or effected any short sale, option or equity swap
transaction in or with respect to the Common Stock or any other derivative
security transaction the purpose or effect of which is to hedge or transfer to a
third party all or any part of the risk of loss associated with the ownership of
the Shares by the Purchaser.

         6.       Restrictions on Transferability of Shares; Compliance with
Securities Act.

                  6.1.     Restrictions on Transferability. The Shares shall not
be resold or otherwise transferred except in a transaction registered under the
Securities Act and applicable state securities laws unless counsel to the
Company shall advise the Company that such transfer may be effected without such
registration.

                  6.2.     Restrictive Legend. Until and unless the Shares are
registered under the Securities Act, each certificate representing the Shares
shall bear substantially the following legend (in addition to any legends
required under applicable state securities laws):

                  THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED
                  UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR
                  UNDER THE SECURITIES LAWS OF ANY STATE. THESE SECURITIES ARE
                  SUBJECT TO

                                       7
<PAGE>

                  RESTRICTIONS ON TRANSFERABILITY AND RESALE AND MAY NOT BE
                  TRANSFERRED OR RESOLD EXCEPT AS PERMITTED UNDER THE ACT AND
                  THE APPLICABLE STATE SECURITIES LAWS, PURSUANT TO REGISTRATION
                  OR EXEMPTION THEREFROM. THE ISSUER OF THESE SECURITIES MAY
                  REQUIRE AN OPINION OF COUNSEL IN FORM AND SUBSTANCE
                  SATISFACTORY TO THE ISSUER TO THE EFFECT THAT ANY PROPOSED
                  TRANSFER OR RESALE IS IN COMPLIANCE WITH THE ACT AND ANY
                  APPLICABLE STATE SECURITIES LAWS.

                  6.3      Transfer of Shares. Each Purchaser hereby covenants
with the Company not to make any sale of the Shares except either (a) a sale of
Shares in accordance with the Registration Statement, in which case the
Purchaser covenants to comply with the requirement of delivering a current
prospectus, (b) a sale of Shares in accordance with Rule 144, in which case the
Purchaser covenants to comply with Rule 144 and to deliver such additional
certificates and documents as the Company may reasonably request, or (c) in
accordance with another exemption from the registration requirements of the
Securities Act. The legend set forth in Section 6.2 will be removed from a
certificate representing Shares following and in connection with any sale of
Shares pursuant to subsection (a) or (b) hereof but not in connection with any
sale of Shares pursuant to subsection (c) hereof. The Company will substitute
one or more replacement certificates without the legend at the request of the
Purchaser promptly after such time as the Registration Statement becomes
effective.

         7.       Miscellaneous.

                  7.1      Survival of Representations and Warranties. All
representations and warranties contained herein shall survive the execution and
delivery of this Agreement, any investigation at any time made by or on behalf
of the Purchasers, and the sale and purchase of the Shares and payment therefor.

                  7.2.     Entire Agreement. This Agreement contains the entire
agreement between the parties with respect to the subject matter hereof and
supersedes all prior and contemporaneous arrangements or understandings with
respect thereto.

                  7.3.     Headings. The headings of the sections of this
Agreement have been inserted for convenience of reference only and do not
constitute a part of this Agreement.

                  7.4.     Choice of Law. It is the intention of the parties
that the internal laws of the State of California, without regard to the body of
law controlling conflicts of law, shall govern the validity of this Agreement,
the construction of its terms and the interpretation of the rights and duties of
the parties set forth herein.

                  7.5.     Counterparts. This Agreement may be executed
concurrently in two or more counterparts, each of which shall be deemed an
original, but all of which together shall constitute one and the same
instrument.

                  7.6.     Assignment; Parties in Interest. This Agreement may
not be pledged, assigned or otherwise transferred by the Purchasers except by
operation of law but all the terms and provision of this Agreement shall be
binding upon and inure to the benefit of and be enforced by the successors in
interest of the parties hereto. Each successive transferee of the Purchasers
shall be deemed to be a Purchaser for the purpose of Section 5 of this
Agreement.

                  7.7.     Amendments. No amendment, modification, waiver,
discharge or termination of any provision of this Agreement nor consent to any
departure by the Purchasers or the Company therefrom shall in any event be
effective unless the same shall be in writing and signed by the party to be
charged with enforcement, and then shall be effective only in the specific
instance and for the purpose for which given. No course of dealing between the
parties hereto shall operate as an amendment of, or a waiver of any right under,
this Agreement.

                  7.8.     Severability. Whenever possible, each provision of
this Agreement shall be interpreted in such manner as to be effective and valid,
but if any provision of this Agreement is held to be invalid or unenforceable in
any respect, such invalidity or unenforceability shall not render invalid or
unenforceable any other provision of this Agreement.

                  7.9.     Notices. All notices, requests, consents and other
communications hereunder to any party shall be deemed to be sufficient if
contained in a written instrument delivered in person or sent by telecopy,
nationally recognized overnight courier or first class registered or certified
mail, return receipt requested, postage prepaid, addressed to such party at the
address set forth below or such other address as may hereafter be designated in
writing by such party to the other party:

                                       8
<PAGE>

                           If to the Company, to:
                           Questcor Pharmaceuticals, Inc.
                           3260 Whipple Road
                           Union City, California 94587
                           Attn: CFO

                           With a copy to:
                           Latham & Watkins LLP
                           701 "B" Street, Suite 2100
                           San Diego, California 92101
                           Attn: David A. Hahn, Esq.

                           If to the Purchaser, to:
                           the address set forth on the
                           signature page of this Agreement

                                [SIGNATURE PAGES FOLLOW]

                                       9

<PAGE>

                  IN WITNESS WHEREOF, the parties have caused this Common Stock
Purchase Agreement to be duly executed and delivered by their proper and duly
authorized representatives as of the day and year first above written

                                                 Questcor Pharmaceuticals, Inc.

                                                 By:____________________________
                                                    Name:
                                                    Title:

                                       10
<PAGE>

                   PURCHASER SIGNATURE PAGE AND QUESTIONNAIRE

         The undersigned Purchaser hereby executes the Common Stock Purchase
Agreement with Questcor Pharmaceuticals, Inc. (the "Company") and hereby
authorizes this signature page to be attached to a counterpart of such document
executed by a duly authorized officer of the Company.

No. of shares of Common Stock
to be Purchased: [__]                                [Purchaser Name]

Cash Consideration:                                  By:________________________
$[__]                                                   Name:
                                                        Title:
No. of Warrants to be
Surrendered to the Company
for Cancellation: [__]

Warrant Valuation:
$[__]

Aggregate Purchase
Price:  $[__]

Name in which shares of Common Stock are to be registered:______________________

Address of registered holder:                             ______________________

                                                          ______________________

Social Security or Tax ID No. of registered holder:       ______________________

Contact name and telephone number regarding
Settlement and registration:                              ______________________
                                                          Name

                                                          ______________________
                                                          Telephone Number

                                       11