X0304 4 2012-03-19 0 0001113481 MEDICINES CO /DE MDCO 0001277478 SBLENDORIO GLENN 8 SYLVAN WAY PARSIPPANY NJ 07054 1 1 0 0 President & CFO Common Stock 2012-03-19 4 M 0 625 7.31 A 106491 D Common Stock 2012-03-19 4 S 0 625 20.39 D 105866 D Option (right to buy) 7.31 2012-03-19 4 M 0 625 0 D 2020-02-19 Common Stock 625 15625 D 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 $20.39 and $20.41 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 informaton regarding the number of shares sold at each separate price. As of 3/18/2012, the original grant (30,000 shares granted on 2/19/2010) was vested with respect to 16,250 of the shares covered thereby and the remaining 13,750 shares covered by this option vest in equal monthly installments ending on 02/19/2014. After the exercise of the options reported hereby, as of 3/20/2012, 1,250 of the shares covered by the option were vested but not exercised. Glenn Sblendorio 2012-03-21