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                                                                    EXHIBIT 4.2


                     AMENDMENT NO. 1 TO THE RIGHTS AGREEMENT


         AMENDMENT NO. 1, dated as of December 15, 1998, to the Rights Agreement
(the "Rights Agreement") dated as of June 1, 1995, between ENVOY CORPORATION, a
Tennessee corporation (the "Company"), as successor to NEW ENVOY, INC., and
FIRST UNION NATIONAL BANK, a national banking institution, as Rights Agent (the
"Rights Agent"), as successor to FIRST UNION NATIONAL BANK OF NORTH CAROLINA.

         WHEREAS the Company is entering into an Agreement and Plan of Merger
(as the same may be amended from time to time, the "Merger Agreement") among the
Company, Quintiles Transnational Corp., a North Carolina corporation ("Parent"),
and QELS Corp., a Tennessee corporation and a wholly owned subsidiary of Parent
("Sub"), providing for transactions (collectively, the "Merger") pursuant to
which, among other things, the Company will become a wholly owned subsidiary of
Parent and the former stockholders of the Company will receive the Merger
Consideration (as defined in the Merger Agreement); and

         WHEREAS the parties desire to amend the Rights Agreement in connection
with the execution and delivery of the Merger Agreement.

         NOW, THEREFORE, in consideration of the foregoing and the mutual
agreements herein set forth, the parties hereby agree as follows:

         1. The definition of "Acquiring Person" set forth in Section l(a) of
the Rights Agreement is hereby amended by adding the following sentence to the
end of that definition:

                  Notwithstanding the foregoing, no Person shall be or become an
         Acquiring Person by reason of (i) the execution and delivery of the
         Agreement and Plan of Merger dated as of December 15, 1998, among the
         Company, Quintiles Transnational Corp., a North Carolina corporation
         ("Parent"), and QELS Corp., a Tennessee corporation ("Sub") (as amended
         from time to time, the "Merger Agreement"), or the execution of any
         amendment thereto, (ii) the execution and delivery of the Stock Voting
         Agreement dated as of December 15, 1998, among Parent and the
         stockholders whose names appear on Schedule A thereto (as amended from
         time to time, the "Stock Voting Agreement") or the performance by any
         party of its obligations thereunder or the execution of any amendment
         thereto, (iii) the acquisition of beneficial ownership of Common Stock
         by Parent or Sub pursuant to or in connection with the Merger (as
         defined in the Merger Agreement) or the Stock Voting Agreement, or 
         (iv) the consummation of the other transactions contemplated by the 
         Merger Agreement or the Stock Voting Agreement.



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         2. Section 7(a) of the Rights Agreement shall be amended to read in its
entirety as follows:

                  (a) At any time after the Exercisability Date and prior to the
         earliest of (i) the consummation of the Merger, (ii) the Close of
         Business on February 2, 2005 (the "Final Expiration Date"), and (iii)
         the time at which the Rights are redeemed as provided in Section 23
         hereof (the "Redemption Date") (the earliest of (i), (ii) and (iii)
         being the "Expiration Date"), the registered holder of any Rights
         Certificate may, subject to the provisions of Section 7(e) hereof,
         exercise the Rights evidenced thereby in whole or in part upon
         surrender of the Rights Certificate, with the form of election to
         purchase and the certificate on the reverse side thereof duly executed,
         to the Rights Agent at the office of the Rights Agent designated for
         such purpose, together with payment of the aggregate Exercise Price (as
         hereinafter defined) for the number of shares of Preferred Stock (or,
         following a Triggering Event, other securities, cash or other assets,
         as the case may be) for which such surrendered Rights are then
         exercisable.

         3. The definition of "Stock Acquisition Date" included in Section 1(bb)
of the Rights Agreement shall be amended by adding the following sentence to the
end of such definition:

                  Notwithstanding anything else set forth in this Agreement, a
         Stock Acquisition Date shall not be deemed to have occurred by reason
         of (i) the public announcement, public disclosure, execution and
         delivery or amendment of the Merger Agreement or the Stock Voting
         Agreement, (ii) the performance by any party of its obligations under
         the Merger Agreement or the Stock Voting Agreement, (iii) the
         acquisition of beneficial ownership of Common Stock by Parent or Sub
         pursuant to the Merger or the Stock Voting Agreement or (iv) the
         consummation of any of the other transactions contemplated by the
         Merger Agreement or the Stock Voting Agreement.

         4. Section 3(a) of the Rights Agreement shall be amended by adding the
following sentence to the end thereof:

                  Notwithstanding anything else set forth in this Agreement, no
         Exercisability Date shall be deemed to have occurred by reason of (i)
         the public announcement, public disclosure, execution and delivery or
         amendment of the Merger Agreement or the Stock Voting Agreement, (ii)
         the performance by any party of its obligations under the Merger
         Agreement or the Stock Voting Agreement, (iii) the acquisition of
         beneficial ownership of Common Stock by Parent or Sub pursuant to the
         Merger or the Stock Voting Agreement or (iv) the consummation of any of
         the other transactions contemplated by the Merger Agreement or the
         Stock Voting Agreement.

                                            

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         5. The first paragraph of Section 13(c) of the Rights Agreement shall
be amended by adding the following phrase to the beginning thereof:

            Other than transactions contemplated by the Merger Agreement or the
         Stock Voting Agreement,

         6. The Rights Agreement, as amended by this Amendment, shall remain in
full force and effect in accordance with its terms. Capitalized terms used but
not otherwise defined herein shall have the meanings ascribed to them in the
Rights Agreement.

         7. This Amendment shall be deemed to be a contract made under the laws
of the State of Tennessee and for all purposes shall be governed by and
construed in accordance with the laws of such State applicable to contracts to
be made and performed entirely within such State. This Amendment may be executed
in any number of counterparts, each of such counterparts shall for all purposes
be deemed to be an original, and all such counterparts shall together constitute
but one and the same instrument. If any term, provision, covenant or restriction
of this Amendment is held by a court of competent jurisdiction or other
authority to be invalid, void or unenforceable, the remainder of the terms,
provisions, covenants and restrictions of this Amendment shall remain in full
force and effect and shall in no way be affected, impaired or invalidated.



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         IN WITNESS WHEREOF, the parties herein have caused this Amendment to be
duly executed and attested, all as of the date and year first above written.



                                         ENVOY CORPORATION


                                         By: /s/ Kevin M. McNamara
                                             ----------------------------------
                                         Name:    Kevin M. McNamara
                                         Title:   Senior Vice President and
                                                  Chief Financial Officer



                                         FIRST UNION NATIONAL BANK,
                                         as Rights Agent


                                         By: /s/ Patty McCool
                                             ----------------------------------
                                         Name:    Patty McCool
                                         Title:   Assistant Vice President







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