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                                                                   EXHIBIT 10.22


                                SECOND AMENDMENT
                                     TO THE
                    CAREMARK RX, INC. 1993 STOCK OPTION PLAN
               (FORMERLY THE AMENDED & RESTATED MEDPARTNERS, INC.
                             1993 STOCK OPTION PLAN)

         This Second Amendment to the Caremark Rx, Inc. 1993 Stock Option Plan
(formerly the Amended & Restated Medpartners, Inc. 1993 Stock Option Plan) (the
"Plan") to be effective as of January 12, 2001.

                                   WITNESSETH:

         WHEREAS, Caremark Rx, Inc. (the "Company") currently sponsors and
maintains the Caremark Rx, Inc. 1993 Stock Option Plan (formerly the Amended &
Restated Medpartners, Inc. 1993 Stock Option Plan) (the "Plan"); and

         WHEREAS, Section 11 of the Plan grants the Compensation Committee of
the Board the power at any time to amend the Plan, and the Compensation
Committee now wishes to amend the Plan to modify the vesting provisions for
options granted under the Plan on and after January 12, 2001;

         NOW, THEREFORE, the Plan is hereby amended as indicated below:

                                       1.

         Section 6.4 of the Plan is amended effective as of January 12, 2001, to
read as follows:

                  6.4      Vesting of Options. Except as set forth by the
         Committee in the applicable Option Agreement, Options shall vest and
         become exercisable as follows:

                  (a)      34% of the Options shall vest on the Grant Date;

                  (b)      33% of the Options granted shall vest on each of the
         first anniversary and second anniversary of the Grant Date; provided,
         however, that for Options granted prior to January 12, 2001, if during
         the first year after the Grant Date, the stock price of the Common
         Stock closes at or above $12.00 (or such other price as determined by
         the Committee and set forth in the applicable Option Agreement) for any
         twenty (20) out of thirty (30) consecutive trading days, the 33% of the
         Options due to vest on the first anniversary of the Grant Date shall
         vest immediately at the end of such 20th day, and provided, however,
         that for Options granted prior to January 12, 2001, if during the
         second year after the Grant Date, the stock price of the Common Stock
         closes at or above $18.00 (or such other price as determined by the
         Committee and set forth in the applicable Option



                             Second Amendment to the
                    Caremark Rx, Inc. 1993 Stock Option Plan
                                     Page 1


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         Agreement) for any twenty (20) out of thirty (30) consecutive trading
         days, the 33% of the Options due to vest on the second anniversary of
         the Grant Date shall vest immediately at the end of such 20th day.

                                       2.

         The name of the Plan is changed effective as of January 12, 2001 from
the Amended & Restated Medpartners, Inc. 1993 Stock Option Plan to the Caremark
Rx, Inc. 1993 Stock Option Plan. All references in any Company documents to the
Amended & Restated Medpartners, Inc. 1993 Stock Option Plan shall, after January
12, 2001, be a reference to the Caremark Rx, Inc. 1993 Stock Option Plan.

                                       3.

         All other provisions of the Plan not inconsistent herewith are hereby
confirmed and ratified.

                       Approved by the Board of Directors
                       by resolutions on January 12, 2001.



                             Second Amendment to the
                    Caremark Rx, Inc. 1993 Stock Option Plan
                                     Page 2