SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934


                              The Medicines Company
                                (Name of Issuer)


                         Common Stock, $0.001 par value
                         (Title of Class of Securities)


                                    584688105
                                 (CUSIP Number)


                                  June 22, 2006
             (Date of Event Which Requires Filing of this Statement)

Check the following box to designate the rule pursuant to which the Schedule is
filed:

  [ ] Rule 13d-1(b)
  [X] Rule 13d-1(c)
  [ ] Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).








CUSIP NO. 584688105

   1.    NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
         (ENTITIES ONLY)
         D. E. Shaw & Co., L.P.
         13-3695715

   2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
         (A) [ ]
         (B) [ ]

   3.    SEC USE ONLY

   4.    CITIZENSHIP OR PLACE OF ORGANIZATION
         Delaware

NUMBER OF                 5.    SOLE VOTING POWER
SHARES                          -0-
BENEFICIALLY
OWNED BY                  6.    SHARED VOTING POWER
EACH                            2,528,405
REPORTING
PERSON WITH               7.    SOLE DISPOSITIVE POWER
                                -0-

                          8.    SHARED DISPOSITIVE POWER
                                2,528,405

   9.    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         2,528,405

   10.   CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
         (SEE INSTRUCTIONS)  [ ]

   11.   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
         5.0%

   12.   TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
         IA, PN






CUSIP NO. 584688105

      1.   NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE
           PERSONS (ENTITIES ONLY)
           David E. Shaw

      2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
           (A) [ ]
           (B) [ ]

      3.   SEC USE ONLY

      4.   CITIZENSHIP OR PLACE OF ORGANIZATION
           United States

NUMBER OF                 5.    SOLE VOTING POWER
SHARES                          -0-
BENEFICIALLY
OWNED BY                  6.    SHARED VOTING POWER
EACH                            2,528,405
REPORTING
PERSON WITH               7.    SOLE DISPOSITIVE POWER
                                -0-

                          8.    SHARED DISPOSITIVE POWER
                                2,528,405

      9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
           2,528,405

      10. CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
          (SEE INSTRUCTIONS) [ ]

      11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
           5.0%

      12.  TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
            IN








ITEM 1.
     (A)          NAME OF ISSUER
                  The Medicines Company

     (B)          ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES
                  8 Campus Drive
                  Parsippany, NJ 07054

ITEM 2.
     (A)          NAME OF PERSON FILING
                  D. E. Shaw & Co., L.P.
                  David E. Shaw

     (B)          ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE
                  The business address for each reporting person is:
                  120 W. 45th Street, Tower 45, 39th Floor
                  New York, NY 10036

     (C)          CITIZENSHIP
                  D. E. Shaw & Co., L.P. is a limited partnership organized
                  under the laws of the state of Delaware.
                  David E. Shaw is a citizen of the United States of America.

     (D)          TITLE OF CLASS OF SECURITIES
                  Common Stock, $0.001 par value

     (E)          CUSIP NUMBER
                  584688105

ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULE 13D-1(B) OR 13D-2(B) OR (C),
        CHECK WHETHER THE PERSON FILING IS A:

Not applicable

ITEM 4. OWNERSHIP

As of June 28, 2006:

(a) Amount beneficially owned:

    D. E. Shaw & Co., L.P.:            2,528,405 shares
                                       This is composed of (i) 2,445,351 shares
                                       in the name of D. E. Shaw Meniscus
                                       Portfolios, L.L.C., and (ii) 83,054
                                       shares in the name of D. E. Shaw Valence
                                       Portfolios, L.L.C.

    David E. Shaw:                     2,528,405 shares
                                       This is composed of (i) 2,445,351 shares
                                       in the name of D. E. Shaw Meniscus
                                       Portfolios, L.L.C., and (ii) 83,054
                                       shares in the name of D. E. Shaw Valence
                                       Portfolios, L.L.C.

(b) Percent of class:
    D. E. Shaw & Co., L.P.:            5.0%
    David E. Shaw:                     5.0%

(c) Number of shares to which the person has:
    (i)  Sole power to vote or to direct the vote:
         D. E. Shaw & Co., L.P.:                         -0- shares
         David E. Shaw:                                  -0- shares

    (ii) Shared power to vote or to direct the vote:
         D. E. Shaw & Co., L.P.:                         2,528,405 shares
         David E. Shaw:                                  2,528,405 shares



    (iii) Sole power to dispose or to direct the
          disposition of:
          D. E. Shaw & Co., L.P.:                               -0- shares
          David E. Shaw:                                        -0- shares

    (iv)  Shared power to dispose or to direct
          the disposition of:
          D. E. Shaw & Co., L.P.:                               2,528,405 shares
          David E. Shaw:                                        2,528,405 shares

David E. Shaw does not own any shares directly. By virtue of David E. Shaw's
position as President and sole shareholder of D. E. Shaw & Co., Inc., which is
the general partner of D. E. Shaw & Co., L.P., which in turn is the managing
member and investment adviser of D. E. Shaw Valence Portfolios, L.L.C., and the
investment adviser of D. E. Shaw Meniscus Portfolios, and by virtue of David E.
Shaw's position as President and sole shareholder of D. E. Shaw & Co. II, Inc.,
which is the managing member of D. E. Shaw & Co., L.L.C., which in turn is the
managing member of D. E. Shaw Meniscus Portfolios, L.L.C., David E. Shaw may be
deemed to have the shared power to vote or direct the vote of, and the shared
power to dispose or direct the disposition of, the 2,528,405 shares as described
above constituting 5.0% of the outstanding shares and, therefore, David E. Shaw
may be deemed to be the beneficial owner of such shares. David E. Shaw disclaims
beneficial ownership of such 2,528,405 shares.

ITEM 5.  OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS
Not Applicable

ITEM 6.  OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.
Not Applicable

ITEM 7.  IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE
         SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY OR CONTROL
         PERSON.
Not Applicable

ITEM 8.  IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP
Not Applicable

ITEM 9.  NOTICE OF DISSOLUTION OF GROUP
Not Applicable

ITEM 10. CERTIFICATION
By signing below, each of D. E. Shaw & Co., L.P., and David E. Shaw certify
that, to the best of such reporting person's knowledge and belief, the
securities referred to above were not acquired and are not held for the purpose
of or with the effect of changing or influencing the control of the issuer of
the securities and were not acquired and are not held in connection with or as a
participant in any transaction having such purposes or effect.





SIGNATURE

After reasonable inquiry and to the best of their knowledge and belief, the
undersigned certify that the information set forth in this statement is true,
complete and correct. A Power of Attorney, dated February 24, 2004, granted by
David E. Shaw in favor of Stuart Steckler, is attached hereto.

Dated: July 3, 2006


                                         D. E. Shaw & Co., L.P.

                                         By: /s/ Stuart Steckler
                                             ----------------------------------
                                             Stuart Steckler
                                             Managing Director



                                         David E. Shaw

                                         By: /s/ Stuart Steckler
                                             ----------------------------------
                                             Stuart Steckler
                                             Attorney-in-Fact for David E. Shaw






                                    EXHIBIT 1

                                POWER OF ATTORNEY
                               FOR CERTAIN FILINGS
                    UNDER THE SECURITIES EXCHANGE ACT OF 1934


I, David E. Shaw, hereby make, constitute and appoint each of:

         Anne Dinning,

         Julius Gaudio,

         Lou Salkind,

         Stuart Steckler, and

         Eric Wepsic,

acting individually, as my agent and attorney-in-fact, with full power of
substitution, for the purpose of, from time to time, executing in my name and/or
my capacity as President of D. E. Shaw & Co., Inc. (acting for itself or as the
general partner of D. E. Shaw & Co., L.P. and general partner or managing
member of other entities, any which in turn may be acting for itself or other
entities) all documents, certificates, instruments, statement, other filings,
and amendments to the forgoing (collectively, "documents") determined by such
person to be necessary or appropriate to comply with ownership or control-person
reporting requirements imposed by any United States or non-United States
governmental or regulatory authority, including without limitation Forms 3, 4,
5, 13D, 13F, and 13G required to be filed with the Securities and Exchange
Commission; and delivering, furnishing or filing any such documents with the
appropriate governmental or regulatory authority. Any such determination shall
be conclusively evidenced by such person's execution, delivery, furnishing,
and/or filing of the applicable document.

This power of attorney shall be valid from the date hereof and replaces the
power granted on February 5, 2001, which is hereby cancelled.

IN WITNESS HEREOF, I have executed this instrument as of the date set forth
below.

Date: February 24, 2004

DAVID E. SHAW, as President of
D. E. Shaw & Co., Inc.
/s/David E. Shaw
New York, New York





                                    EXHIBIT 2

                             JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934,
as amended, each of the undersigned Reporting Persons hereby agrees to the joint
filing, along with all other such Reporting Persons, on behalf of each of them
of a statement on Schedule 13G (including amendments thereto) with respect to
the Common Stock, $0.001 par value, of The Medicines Company, and that this
Agreement be included as an Exhibit to such joint filing. This Agreement may be
executed in any number of counterparts, all of which taken together shall
constitute one and the same instrument.

IN WITNESS WHEREOF, each of the undersigned hereby executes this Agreement as of
this 3rd day of July, 2006.




                                      D. E. Shaw & Co., L.P.

                                      By: /s/ Stuart Steckler
                                          -------------------------------------
                                          Stuart Steckler
                                          Managing Director



                                      David E. Shaw

                                      By: /s/ Stuart Steckler
                                          -------------------------------------
                                          Stuart Steckler
                                          Attorney-in-Fact for David E. Shaw