Abstract
We evaluated whether a drug interaction between intravenous nitrates and heparin exists. Study 1: Twelve patients with acute coronary syndrome (acute myocardial infarction 6, unstable angina 6) were enrolled. Intravenous infusion of heparin was started with intravenous nitroglycerin for five hours, followed by intravenous isosorbide dinitrate for the next five hours, and switched back to intravenous nitroglycerin for the final five hours. Study 2: Nine patients with stable effort angina or chest pain syndrome were enrolled. Intravenous infusion of heparin was started alone for twelve hours at least, then intravenous infusion of nitrate was added onto the prior drip infusion of heparin on the second day, and switched back to intravenous infusion of heparin alone on the third day. Activated clotting time (ACT), activated partial thromboplastin time (APTT), and antithrombin III (AT-III) measurements were taken every five hours (Study 1), or at every drug exchange point (Study 2). Nitrates did not induce attenuation in the anticoagulation effect of heparin. Thus there was no interaction between nitroglycerin or isosorbide dinitrate and heparin in the Japanese.
