X0306 4 2013-02-19 0 0001113481 MEDICINES CO /DE MDCO 0001277478 SBLENDORIO GLENN 8 SYLVAN WAY PARSIPPANY NJ 07054 1 1 0 0 Executive VP & CFO Common Stock 2013-02-19 4 S 0 2552 31.81 D 94730 D Common Stock 2013-02-20 4 M 0 25000 20.11 A 119730 D Common Stock 2013-02-20 4 S 0 25000 32.51 D 94730 D Option(right to buy) 20.11 2013-02-20 4 M 0 25000 0 D 2016-03-03 Common Stock 25000 25000 D Represents the number of shares sold to cover the tax expense associated with the vesting of restricted shares held by Mr. Sblendorio pursuant to his Restricted Stock Agreements with the Company. The range of prices for the transactions reported on this line is between $31.65 and $31.92 per share. The price reported above reflects the weighted average sales price. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price. The common stock sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 program adopted by Mr. Sblendorio on February 18, 2011. The range of prices for the transactions reported on this line is between $32.50 and $32.62 per share. The price reported above reflects the weighted average sales price. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price. As of 2/20/2013, the original grant (150,000 shares granted on 3/03/2006) was fully vested. After the exercise of the options reported hereby, as of 2/20/2013, 25,000 of the shares covered by the option were vested but not exercised. /s/ Paul M. Antinori as Attorney-In-Fact for Glenn Sblendorio 2013-02-21