Nitromed (NTMD) 10-Q 2005 Q1 Quarterly report

QuickLinks -- Click here to rapidly navigate through this document

Exhibit 32.1

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

        In connection with the Quarterly Report on Form 10-Q of NitroMed, Inc. (the "Company") for the period ended March 31, 2005 as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, Michael D. Loberg, Ph.D., President and Chief Executive Officer of the Company, hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

(1)

The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and



(2)

The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Dated: May 5, 2005 /s/  MICHAEL D. LOBERG, PH.D.      Michael D. Loberg, Ph.D.
President and Chief Executive Officer

QuickLinks

Exhibit 32.1