Exhibit 24.1

POWER OF ATTORNEY

      Know all by these presents that the undersigned hereby
constitutes and appoints each of Christopher Visioli and Stephen
Rodin, signing singly, as the undersigned's true and lawful
attorney-in-fact:

1) to execute for and on behalf of the undersigned, in the
undersigned's capacity as an officer of The Medicines Company
(the 'Company'), Forms 3, 4, and 5 in accordance with Section
16(a) of the Securities Exchange Act of 1934 and the rules
thereunder, and any other forms or reports the undersigned may
be required to file with the United States Securities and
Exchange Commission in connection with the undersigned's
ownership, acquisition, or disposition of securities of the
Company, including, but not limited to, Form 144 and Form ID
(collectively, 'SEC Filings');

2) to do and perform any and all acts for and on behalf of the
undersigned which may be necessary or desirable to complete
and execute any such SEC Filings and timely file such form
with the United States Securities and Exchange Commission and
any stock exchange or similar authority; and

3) to take any other action of any type whatsoever in
connection with the foregoing which, in the opinion of such
attorney-in-fact, may be of benefit  to, in the best interest
of, or legally required by, the undersigned, it being
understood that the documents executed by such attorney-in-
fact on behalf of the undersigned pursuant to this Power of
Attorney shall be in such form and shall contain such terms
and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

      The undersigned hereby grants to each such attorney-in-
fact full power and authority to do and perform any and every
act and thing whatsoever requisite, necessary, or proper to be
done in the exercise of any of the rights and powers herein
granted, as fully to all intents and purposes as the
undersigned might or could do if personally present, with full
power of substitution or revocation, hereby ratifying and
confirming all that such attorney-in-fact, or such attorney-
in-fact's substitute or substitutes, shall lawfully do or
cause to be done by virtue of this Power of Attorney and the
rights and powers herein granted.  The undersigned
acknowledges that the foregoing attorneys-in-fact, in serving
in such capacity at the request of the undersigned, are not
assuming, nor is the Company assuming, any of the
undersigned's responsibilities to comply with Section 16 of
the Securities Exchange Act of 1934 or Rule 144 of the
Securities Act of 1933.

      This Power of Attorney shall remain in full force and
effect until the undersigned is no longer required to file
reports and other forms under Section 16 of the Securities
Exchange Act of 1934 and Rule 144 of the Securities Act of
1933 with respect to the undersigned's holdings of and
transactions in securities of the Company, unless (i) earlier
revoked by the undersigned in a signed writing delivered to
the foregoing attorneys-in-fact, or (ii) with respect to each
individual attorney-in-fact, upon their retirement or
termination of employment with the Company.

      IN WITNESS WHEREOF, the undersigned has caused this
Power of Attorney to be executed as of this 18th day of
December, 2018.

      					By: /s/ Mark Timney
       					Name: Mark Timney