1

                                                                  EXHIBIT 10.33


CONFIDENTIAL


                          FIRST AMENDMENT TO AGREEMENT
                                 BY AND BETWEEN
               ABBOTT LABORATORIES AND SONUS PHARMACEUTICALS, INC.


        THIS FIRST AMENDMENT TO AGREEMENT ("Amendment") is dated January 31,
1999 ("Amendment Effective Date"), by and between Abbott Laboratories, an
Illinois corporation with principal offices at 100 Abbott Park Road, Abbott
Park, Illinois 60064-3500 ("ABBOTT") and SONUS Pharmaceuticals, Inc., a Delaware
corporation with principal offices at 22026 20th Avenue, S.E., Suite 102,
Bothell, Washington 98021 ("SONUS").

                                    RECITALS

        WHEREAS, ABBOTT and SONUS have previously entered into the Agreement
dated May 14, 1996 ("Agreement") whereby SONUS granted to ABBOTT and ABBOTT
obtained from SONUS certain exclusive marketing rights to certain ultrasound
contrast agents, including EchoGen(R), in the United States in accordance with
the terms and conditions thereof;

        WHEREAS, Abbott International, Ltd. ("Abbott International") and SONUS
entered into an International License Agreement, dated October 1, 1996 whereby
SONUS granted to Abbott International and Abbott International obtained from
SONUS certain exclusive marketing rights to EchoGen(R) in certain areas outside
the United States in accordance with the terms and conditions thereof
("International Agreement"), which agreement shall be amended as of the
Amendment Effective Date as specifically set forth in the amendment to such
agreement;

        WHEREAS, ABBOTT and SONUS entered into a Development and Supply
Agreement, dated May 6, 1993, whereby ABBOTT assisted in the manufacturing
scale-up for EchoGen(R) and agreed to manufacture EchoGen(R) for SONUS ("Supply
Agreement"); and

                      [*] CONFIDENTIAL PORTIONS OMITTED AND
                        FILED SEPARATELY WITH COMMISSION


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        WHEREAS, ABBOTT and SONUS desire to amend the Agreement, as set forth in
this Amendment, simultaneously with amending the International Agreement and
executing a letter of understanding with respect to the amendment of the Supply
Agreement as soon a reasonably practicable;

        NOW, THEREFORE, in consideration of the premises and the mutual promises
and covenants set forth below, ABBOTT and SONUS mutually agree as follows:

1.      ARTICLE 1 - DEFINITIONS. Capitalized terms used in this Amendment and
not otherwise defined in this Amendment shall have the meanings set forth in the
Agreement. Article 1 shall be amended by adding the following definitions:

        1.21 "Cardiology Indication" means an indication for EchoGen(R) Emulsion
which is substantially equivalent to the following: [*]

        1.22 "Radiology Indication" means an indication for EchoGen(R) Emulsion
which is substantially equivalent to the following: [*]

        1.23 "Supply Agreement" shall mean the EchoGen(R) Contrast Agent
Development and Supply Agreement between ABBOTT and SONUS as amended and
restated as of the Amendment Effective Date as such agreement may be further
amended from time to time.

        1.24 "Cardiology/Radiology Approval Date" means the later to occur of
(i) the date of FDA approval for the Cardiology Indication, and (ii) the date of
FDA approval for the Radiology Indication.

2.      APPENDIX 2.3 - RESEARCH AND DEVELOPMENT PAYMENT SCHEDULE shall be
deleted and replaced with the amended Appendix 2.3, attached to this Amendment.
SONUS acknowledges and agrees that the amounts referred to in items 1, 2, 3, 4,
and 5 of the Appendix 2.3, as amended by this Amendment, have been paid by
ABBOTT to SONUS in full prior to the Amendment Effective Date.



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3.      SECTION 2.4 - ADDITIONAL CLINICAL RESEARCH shall be deleted in its
entirety and replaced with the following:

        "2.4   Additional Clinical Research.

               (A) ABBOTT shall have no obligation to provide financial support
        for research and development, including clinical research, to be
        conducted by SONUS except for the amounts payable by ABBOTT as set forth
        in Section 2.3 and Article 7. SONUS shall promptly notify ABBOTT in
        writing if SONUS desires that ABBOTT fund expenditures for clinical
        research in addition to that set forth in the Plan to support research
        and development for ultrasound diagnostic applications for indications
        other than the Cardiology Indication and the Radiology Indication. Such
        notice from SONUS shall include a budget for clinical research and a
        preliminary clinical plan. ABBOTT shall communicate its decision whether
        or not to financially participate in such clinical research within
        ninety (90) days of receipt of the budget and clinical plan from SONUS.
        ABBOTT shall be under no obligation to financially support such
        additional clinical research. If ABBOTT desires to participate
        financially in such additional clinical research, and communicates its
        decision to participate in writing, ABBOTT shall reimburse SONUS for
        SONUS' documented incremental costs and expenses incurred with respect
        to the additional clinical research described in Sections 2.2 and 2.6
        and which are mutually agreed upon by the parties in writing. SONUS will
        document the costs incurred during the studies approved by ABBOTT and
        submit detailed cost summaries to ABBOTT on a monthly basis. ABBOTT will
        reimburse SONUS for such documented costs incurred within thirty (30)
        days of receipt of the cost summaries, subject to the funding
        limitations set forth herein. If SONUS determines that there will be any
        material variance in the actual costs, as compared to the approved
        funding, SONUS will promptly notify ABBOTT and obtain prior written
        approval from ABBOTT in advance of incurring the additional costs. Any
        funding by ABBOTT in addition to that indicated above may be approved by
        ABBOTT at its sole discretion. Furthermore, ABBOTT may terminate its
        participation in and reimbursement of the costs of the clinical



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        research if ABBOTT has any concern over safety and/or efficacy issues at
        any time. For any such cost and expenses ABBOTT funds, SONUS shall
        reimburse ABBOTT for fifty percent (50%) of such costs and expenses
        funded by ABBOTT, plus interest at the prime rate of interest (as
        published in the Wall Street Journal, Midwest Edition on the date on
        which ABBOTT provides such funding) ("Reimbursement Amount").
        Reimbursement Amounts shall be aggregated on an annual basis and must be
        repaid by SONUS within five (5) years from the end of the calendar year
        in which the Reimbursement Amount was advanced by ABBOTT as provided in
        Subsections (i), (ii), (iii) and (iv) below. Interest on outstanding
        Reimbursement Amounts shall be accrued monthly. Reimbursement Amounts
        shall be paid by SONUS to ABBOTT, by either, at the option of SONUS:

               (i) reimbursing ABBOTT in cash for the Reimbursement Amount
               within five (5) years from the end of the calendar year in which
               such Reimbursement Amount is paid by ABBOTT; or

               (ii) reducing the percentage amounts payable by ABBOTT to SONUS
               as provided in Article 7 at such dates and in such amounts as
               mutually agreed by the parties; or

               (iii) in the event that the net tangible assets of SONUS shall
               fall below an amount equal to the then current Nasdaq National
               Market listing requirement for net tangible assets contained in
               paragraph 4450(a)(3) of the NASD Manual (as such provision may be
               amended from time to time), plus One Million Dollars
               ($1,000,000), reimbursing ABBOTT such Reimbursement Amount with
               interest at the United States prime rate of interest (as
               published in the Wall Street Journal Midwest Edition on the date
               on which ABBOTT funds such reimbursement), by issuing and
               delivering to ABBOTT shares of Common Stock of SONUS having a
               fair market value equal to the Reimbursement Amount pursuant to
               the terms, provisions and conditions of a Securities Purchase
               Agreement in form attached hereto as Appendix 2.4, and which is
               incorporated herein by this reference; or



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               (iv) reimbursing ABBOTT partially in cash pursuant to Section
               2.4(A)(i) and the remainder in SONUS Common Stock pursuant to
               Section 2.4(A)(iii). 

        SONUS shall provide fifteen (15) days prior written notice to ABBOTT of
        the payment option SONUS elects under this Section 2.4(A). In addition,
        the definition of the "Field" set forth in Section 1.6 shall be expanded
        to include the indication(s) funded by ABBOTT pursuant to this Section
        2.4(A).

               (B) If the parties are unable to agree on a reduction of the
        percentage allocations of Revenue Payments payable by ABBOTT to SONUS in
        Article 7 pursuant to Section 2.4(A)(ii) within thirty (30) days of the
        date on which they began discussing such reduction, then the parties
        shall utilize the ADR Procedure under Article 21 to determine the
        reduction in percentage amounts payable by ABBOTT to SONUS in Article 7.
        In such event, from the time the ADR process is initiated and until the
        final decision of the neutral, Abbott, at its option, may withhold from
        payment to SONUS ten percent (10%) of the Revenue Payments due to SONUS
        under Article 7. The neutral shall also determine whether ABBOTT owes to
        SONUS a portion of the Revenue Payment withheld during the ADR, or SONUS
        owes to ABBOTT certain sums. Such amount due by one party to the other
        (if any) shall be due and payable (with interest at the prime rate of
        interest, as published in the Wall Street Journal, Midwest Edition on
        the date on which the decision is delivered) within thirty (30) days of
        the delivery of a decision.

               (C) In the event ABBOTT should terminate its reimbursement of
        costs and expenses incurred by SONUS in connection with any clinical
        research pursuant to Section 2.4(A) prior to the conclusion of such
        clinical research, the parties shall negotiate in good faith to modify
        the percentage allocations of Revenue Payments allocable to such
        additional indications under Section 7.1 to reflect the amount of the
        additional expenditures made by SONUS for such additional clinical
        research, together with such other factors as are appropriate.
        Notwithstanding the foregoing, if within ninety (90) days of the receipt
        of regulatory approval of the Product for such additional indication



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        supported by such clinical research in the United States or the European
        Union (whichever first occurs) ABBOTT pays to SONUS the amount ABBOTT
        would have paid had ABBOTT not terminated such reimbursement with
        interest at the prime rate of interest (as published in the Wall Street
        Journal, Midwest Edition on the date on which the termination took place
        from the date of such unreimbursed expenditures by SONUS to the date of
        payment by ABBOTT), the obligation of SONUS to reimburse ABBOTT as set
        forth above shall continue with respect to all such amounts paid by
        ABBOTT.
               (D) If ABBOTT determines not to provide additional financial
        support for such additional clinical research as provided in Section
        2.4(A) and SONUS proceeds with the additional research and development,
        then the parties shall negotiate in good faith to modify the percentage
        allocations of Revenue Payments allocable to such additional indications
        under Section 7.1 below to reflect the amount of the expenditures to be
        made by SONUS for such additional clinical research related to such
        additional indications, together with such other factors as are
        appropriate. If the parties are unable to agree upon a reasonable
        modification of the percentage allocation of Revenue Payments within
        thirty (30) days of the date on which they began discussing such
        modification, then the parties shall use the ADR procedure pursuant to
        Article 21 to determine the modification of the percentage allocations
        of Revenue Payments (if any). The provisions of this Section 2.4 shall
        apply only with respect to the new indications for the Product specified
        above and shall not apply to any new product which is subject to the
        right of first refusal pursuant to Article 10."

4.      SECTION 3.2 shall be amended as follows:

        A.     APPENDIX 3.2B - FORECASTED NET SALES ("NET SALES FORECAST"). The
               Net Sales Forecast shall be updated and revised by ABBOTT and
               mutually agreed upon by the parties in good faith.





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        B.     SECTION 3.2(A) second sentence shall be amended as follows:

               "ABBOTT shall use its reasonable best efforts to optimize sales,
               profitability and market share of the Product in the Territory in
               a manner consistent with the efforts which it exerts to optimize
               sales, profitability, and market share of its other products in
               the Territory."

        C.     SECTION 3.2(B) shall be amended by restating the preamble
paragraph and clause (i) as follows:

                      "(B) SONUS shall not have the right to co-promote (as
               defined herein) the Product unless and until such time as SONUS
               has received FDA approval of the Product for both the Cardiology
               Indication and the Radiology Indication. In the event that (and
               after such time as) SONUS has received FDA approval for the
               Product for both the Cardiology Indication and the Radiology
               Indication, SONUS may co-Promote the Product at its own expense
               in the Territory only under the following circumstances:

                             (i) at any time after the first anniversary of the
               First Shipment Date, if ABBOTT's Net Sales to Third Parties are
               below fifty percent (50%) of the mutually agreed upon Net Sales
               Forecast for any two consecutive calendar quarters. SONUS shall
               notify ABBOTT in writing within thirty (30) days of receipt of
               the applicable second quarterly Net Sales report, as set forth in
               Section 7.1, of its intention to co-promote the Product. The Net
               Sales Forecast shall include the material assumptions made in
               preparing the Net Sales Forecast, including without limitation,
               the anticipated Cardiology Indication Approval Date and Radiology
               Indication Approval Date. SONUS' right to co-promote would be
               effective thirty (30) days after the date of ABBOTT's receipt of
               notice from SONUS. If SONUS does not so inform ABBOTT, then SONUS
               shall have waived its right to co-promote the Product with regard
               to that specific failure of ABBOTT to meet its Net Sales Forecast
               for such two (2) consecutive calendar



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               quarters. In the event that the Cardiology/Radiology Approval
               Date does not occur within the time frame contemplated by the
               parties as set forth in Net Sales Forecast, the Net Sales
               Forecast shall be adjusted as mutually agreed by the parties to
               reflect the revised anticipated Cardiology/Radiology Approval
               Date and the specific indications approved, and any material
               changes to the assumptions for the Net Sales Forecast, including
               without limitation, any additional indications which may be
               approved as contemplated in Section 2.4. If the parties are
               unable to agree on such adjustment within thirty (30) days of the
               date on which they began discussing such adjustment, then the
               parties shall utilize the Alternative Dispute Resolution
               Procedure set forth in Section 21 to determine such adjustment."

        D.     SECTION 3.2(C) shall be amended by adding to the beginning
               thereto the following:

                      "In the event that SONUS co-promotes the Product pursuant
               to Section 3.2(B), such co-promotion shall be in a manner
               designed to be complementary to ABBOTT's sales and marketing
               efforts. All SONUS deployment and promotional plans and budgets
               must be reviewed and approved by ABBOTT prior to implementation,
               such approval not to be unreasonably withheld."

5.      SECTION 3.4(A) - PRODUCT MANUFACTURE shall be deleted in its entirety
and replaced with the following:

                      "(A) ABBOTT and SONUS have previously entered into a
               Development and Supply Agreement dated as of May 6, 1993, as
               amended ("Supply Agreement") under which ABBOTT has agreed to
               manufacture the Product for SONUS. SONUS may purchase Product
               under the Supply Agreement to fulfill ABBOTT's purchase orders
               under Section 3.5. All manufacturing of the



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                Product by ABBOTT for sale in the Territory by ABBOTT shall be
                governed by the terms of the Supply Agreement, as amended from
                time to time, and the specifications for the Product in effect
                under the Supply Agreement."

6.      SECTION 3.5 - PRODUCT FORECASTS, ORDERS AND REJECTED PRODUCT shall be
amended by adding at the end thereto Subsection (H) as follows:

                      "(H) ABBOTT and SONUS agree that during the term of the
               Agreement a certain portion of the Product will be packaged [*].
               In the early years following the First Shipment Date of the
               Product [*], a larger percentage of total Unit Sales shall
               consist of [*], whereas, in later years, ABBOTT shall move toward
               marketing and selling a certain portion of the Product [*] in
               accordance with the following guidelines:

                                             [*]

               After the expiration of the Launch Budget Reimbursement Payments
               under Article 6.2 and in the event that actual Unit Sales of [*]
               as a percentage of total Unit Sales exceed the percentage
               thresholds set forth in this subsection (H), ABBOTT and SONUS
               agree to meet to discuss an adjustment of the percentages or
               modifications to [*] or modification to the percentage allocation
               of Revenue Payments under Article 7.1, as appropriate. If the
               parties are unable to agree upon an appropriate and reasonable
               adjustment or modification within thirty (30) days of the date on
               which they began discussing such modification, then the parties
               shall use the ADR procedure pursuant to Article 21 to determine
               an appropriate and reasonable adjustment or modification, if any.

7.      SECTION 3.6 - CLINICAL RESEARCH, REGULATORY AFFAIRS, TECHNICAL
MARKETING/MEDICAL SUPPORT. The last two sentences of subsection (A) are deleted.
Subsections (C) and (D) are added as follows:



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               "3.6.  Clinical Research, Regulatory Affairs, Technical 
Marketing/Medical Support.

                      (C) ABBOTT shall be responsible for required adverse drug
               event reporting to the FDA and will consult with SONUS prior to
               such required reports to allow SONUS to conduct an investigation
               of the event and review all such reports prior to submission to
               the FDA. Notwithstanding the foregoing provisions, however,
               nothing in this Agreement shall require ABBOTT to delay
               submitting any adverse event report beyond the time limit set by
               the FDA. Each party shall promptly notify the other party of all
               communications from and to the FDA regarding the Product.

                      (D) ABBOTT shall be responsible for obtaining
               reimbursement code programs with respect to all federally-funded
               and/or state-funded reimbursement programs. ABBOTT will pursue
               such activities diligently and will use its reasonable best
               efforts to obtain such reimbursement code programs."

8.      ARTICLE 4 - CANADA AND LATIN AMERICA AND OTHER TERRITORIES shall be
deleted in its entirety.

9.      SECTION 5 - LICENSES shall be amended by adding a new Subsection (D) as
follows:

                      "(D) As specified in amended Appendix 2.3 certain
               milestone payments have been conditioned upon the achievement of
               specific milestones relating to the Cardiology Indication and the
               Radiology Indication. Payments due on or after the date of this
               Amendment have been apportioned (i) fifty percent (50%) to
               milestones related to the achievement of the FDA approval of the
               Cardiology Indication for the Product ("Cardiology Milestone
               Payments") and (ii) fifty percent (50%) have been apportioned to
               the achievement of FDA approval of the Radiology Indication (or a
               modification of the Radiology Indication, as may be



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               mutually agreed upon by ABBOTT and SONUS through good faith
               discussions and in writing, through a development plan agreed
               upon and approved by both ABBOTT and SONUS within ninety (90)
               days following the date hereof) for the Product and other
               specific milestones relating to the Radiology Indication
               ("Radiology Milestone Payments").

                      (E) Within one (1) year following the Radiology Prepayment
               Date (as such term is defined on Exhibit A to the Securities
               Purchase Agreement), SONUS shall have the right to request that
               ABBOTT prepay any or all of the Radiology Milestone Payments in
               consideration for the issuance by SONUS to ABBOTT of shares of
               SONUS Common Stock, pursuant to and subject to the terms and
               conditions of a the Securities Purchase Agreement in the form
               attached hereto as Appendix 2.4, the terms and conditions of
               which Securities Purchase Agreement are incorporated herein by
               reference. Anything herein or in the Securities Purchase
               Agreement notwithstanding, SONUS shall not have the right to
               request that Abbott make any prepayment of any Radiology
               Milestone Payment (i) relating to the NDA approval milestone
               unless and until SONUS has received the first FDA approval of the
               Product in the Field, and (ii) relating to the first shipment of
               the Product milestone unless and until the first shipment of the
               Product has occurred. If SONUS does not request prepayment of the
               Radiology Milestone Payments within such one (1) year period as
               provided in the Securities Purchase Agreement, ABBOTT shall not
               be obligated to pay the Radiology Milestone Payments until such
               time as SONUS obtains FDA approval of the Radiology Indication.
               In the event that ABBOTT has prepaid any or all of the Radiology
               Milestone Payments, SONUS shall repay thirty percent (30%) of the
               dollar value of such prepaid amount ("Repayment Amount") to
               ABBOTT if SONUS fails to achieve the Radiology Milestone on or
               before the date which is [*] following the Amendment Effective
               Date. SONUS shall pay to ABBOTT the Repayment Amount by either,
               at the option of SONUS:



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                        (i) repaying ABBOTT the Repayment Amount in the form of
                        cash within ten (10) days following the date which is
                        [*] following the Amendment Effective Date; or

                        (ii) issuing and delivering to ABBOTT a number of shares
                        of Common Stock of SONUS equal to the Repayment Amount
                        pursuant to the terms and conditions of the Securities
                        Purchase Agreement.

10.     SECTION 6.2 - LAUNCH BUDGET REIMBURSEMENT PAYMENTS - shall each be
deleted in its entirety and replaced with the following:

               "6.2 Launch Budget Reimbursement Payments. Each calendar quarter
        following the First Shipment Date and until the earlier to occur of
        either: (a) the last day of the calendar quarter in which achievement of
        Net Sales equal to or greater than fifteen million dollars ($15,000,000)
        in two (2) consecutive calendar quarters, or (b) [*], one party shall
        pay to the other party an amount equal to fifty percent (50%) of the
        excess of Budget Launch Expenses of one party over the Budget Launch
        Expenses of the other party for the same period (e.g. if ABBOTT has
        Budget Launch Expenses of [*] and SONUS has Budget Launch Expenses of
        [*] in the first twelve (12) months of Product sales, the amount to be
        paid by SONUS to ABBOTT is [*]. The payment will be made within sixty
        (60) days of the end of each calendar quarter for the period the launch
        expenses are incurred. In the case of payment to be made by SONUS, the
        amounts payable shall be offset against payments to be made by ABBOTT to
        SONUS as set forth in Article 7. In the case of payments to be made by
        ABBOTT, the payments will be made by wire transfer. Each party shall
        supply to the other party all wire transfer account information. As used
        herein, "Budget Launch Expenses" shall mean the lesser of: (i) [*], or
        (ii) [*]

11.     SECTION 6.3 - LOSS CARRY FORWARD. Section 6.3 shall be deleted in its
entirety and replaced with the following:



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               "6.3 Loss Carry Forward. If a Launch Budget Reimbursement Payment
        as calculated in Section 6.2 is to be made by SONUS to ABBOTT and such
        Launch Budget Reimbursement Payment has not been fully paid by SONUS to
        ABBOTT by the earlier to occur of either: (a) achievement of Net Sales
        equal to or greater than fifteen million dollars ($15,000,000) in two
        (2) consecutive calendar quarters, or (b) [*], then the unpaid amount
        shall be carried forward and offset against Revenue Payments for
        subsequent quarters until such time as the entire Launch Budget
        Reimbursement Payment has been paid or credited to ABBOTT."

12.     SECTION 7.1 - CALCULATION OF REVENUE PAYMENTS - shall be amended by
adding to the end thereof the following:

        "Anything herein to the contrary notwithstanding, the amount of the
        payments to be made by ABBOTT to SONUS as set forth in Article 7 shall
        not be reduced by more than fifty percent (50%) in any calendar quarter
        as a result of the offsets pursuant to Section 6.2. Any offsets which
        otherwise would have been made except for the preceding sentence or for
        any other reason shall be carried forward and applied as offsets against
        future payments to be made by ABBOTT to SONUS as set forth under Article
        7."

13.     SECTION 8.3 - PROHIBITION shall be amended by deleting the initial
phrase "With the exception of purchase under Section 8.1," and replacing it with
the phrase "With the exception of purchase under the terms of this Agreement or
any other written agreement between SONUS and ABBOTT or ABBOTT's Affiliates".

14.     SECTION 16 - NON-COMPETE shall be amended by deleting the first sentence
thereof and replacing it with the following sentence:

                "For a period of [*] after the Amendment Effective Date, each
                party and its Affiliates shall undertake not to market or sell a
                competing product in the Territory to an end user."




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15.     [*] RIGHTS AND NEGOTIATION.

        As of the Amendment Effective Date, SONUS has under development an
ultrasound diagnostic imaging product within the Field which SONUS has
designated as [*]. SONUS and ABBOTT acknowledge and agree that: (i) [*] falls
within the definition of "Product" set forth in Section 1.16 (although all
specific terms and conditions with respect to[*] shall be set forth in a
separate agreement between ABBOTT and SONUS), and (ii) ABBOTT has exclusive
rights to market and sell [*]. SONUS and ABBOTT shall exert all reasonable
efforts to negotiate in good faith, execute and deliver a separate agreement
with respect to [*].

16.     REGISTRATION RIGHTS. SONUS shall, prior to or on the Amendment Effective
Date, cause to be amended and restated the Sonus Pharmaceuticals, Inc. Third
Amended and Restated Registration Rights Agreement dated May 15, 1996, as
amended ("Registration Rights Agreement"), to include the shares of Common Stock
issued by SONUS to ABBOTT and Common Stock issuable upon exercise of the
Warrants pursuant to the Agreement, as amended, and the Securities Purchase
Agreement, as "Registrable Securities" as the term "Registrable Securities" is
defined in the Registration Rights Agreement. The effectiveness of this
Amendment shall be conditioned upon the approval, execution and delivery of the
Registration Rights Agreement, amended and restated as set forth in this Section
16 of the Amendment.

17.     APPENDICES. Appendices of the Agreement are amended as set forth in the
corresponding Appendices attached to this Amendment.

18.     CONFIDENTIALITY. In the event that this Amendment is to be filed with
the Securities and Exchange Commission, ABBOTT and SONUS shall discuss any
request for confidential treatment of certain financial and other terms of this
Amendment and cooperate in the preparation and filing of any confidential
treatment requests submitted to the Securities and Exchange Commission with
respect to this Amendment.



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19.     COUNTERPARTS. This Amendment may be executed in any number of
counterparts, each of which shall be deemed an original, but all together shall
constitute one and the same instrument.

20.     AMENDED TERMS. Except as expressly modified and amended by this
Amendment, all terms and conditions of the Agreement shall remain in full force
and effect.

        IN WITNESS WHEREOF, each of the parties hereto has caused this Agreement
to be executed by its duly authorized representative as of the day and year
first above written.

ABBOTT LABORATORIES                            SONUS PHARMACEUTICALS, INC.



By: /s/ Richard A. Gonzalez                  By: /s/ Michael A. Martino
    -------------------------------------        -------------------------------
    Name:  Richard A. Gonzalez                   Name:  Michael A. Martino
    Title: President, Hospital                   Title: President
           Products Division            





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                                     AMENDED
                                  APPENDIX 1.7

                              INDICATIONS AND USAGE
                             AS OF JANUARY 25, 1998






RADIOLOGY INDICATION

                                             [*]


CARDIOLOGY INDICATION

                                             [*]




   17

                                     AMENDED
                                  APPENDIX 2.3

                            RESEARCH AND DEVELOPMENT
                                PAYMENT SCHEDULE



1.      Execution of definitive Agreement (May 14, 1996) $4 Million
        (Includes $1,000,000 payment for grant of licenses)

2.      Quarterly Milestone Payments*
        Payment 1                                    $1 Million
        Payment 2                                    $1 Million
        Payment 3                                    $1 Million
        Payment 4                                    $1 Million
        Payment 5                                    $1 Million
        Payment 6                                    $1 Million
        Payment 7                                    $1 Million

3.      Filing NDA**  within 15 days                 $2 Million
                      within 105 days                $1 Million
                      within 195 days                $1 Million

4.      NDA acceptance by FDA**
                      within 15 days                 $1 Million
                      within 105 days                $1 Million
                      within 195 days                $1 Million
                      within 285 days                $1 Million

5.      Advisory Panel Approval**
                      within 15 days                 $2 Million
                      within 105 days                $2 Million

6.      NDA Approval **                              $4 Million

7.      First Shipment of Product **                 $4 Million

        *Payments made on January 1, April 1, July 1, and October 1. Payments
        will begin on the first quarter after the Effective Date.

        **For one or more indications which are the Cardiology Indication and
        Radiology Indication defined in Sections 1.21 and 1.22, respectively. Of
        the amount specified in each of item 6 and 7, fifty percent (50%) shall
        be earned based on the FDA approval of the NDA for the Cardiology
        Indication and fifty percent (50%) shall be earned based on FDA approval
        of the NDA for the Radiology Indication. The manner in which these
        milestones are earned and paid is further set forth in the Securities
        Purchase Agreement.






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                                  APPENDIX 2.4


                          SECURITIES PURCHASE AGREEMENT


                                   [ATTACHED]







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