EFFECTIVE AND SAFE DOSE OF INTRACORONARY NICORANDIL IN MAN

Nicorandil is a hybrid of a nitrate and a potassium channel opener, an d has a potent vasodilatory effect on coronary arteries. The effects o f intracoronary injection of nicorandil on coronary circulation were e xamined in 12 adult patients with angiographically normal or near-norm al left coronary arteries to determine the optimal dose of this agent. The intracoronary injection of nicorandil (up to 1 mg over 1 min) dil ated left coronary artery segments in a dose-dependent manner, with no significant effects on systemic hemodynamic parameters. The percent i ncrease in the epicardial coronary artery diameter with 1 mg nicorandi l (31+/-5%, mean+/-SEM) was not significantly different from that with 0.3 mg sublingual nitroglycerin (39+/-5%). Coronary sinus venous oxyg en saturation increased immediately after the intracoronary injection of 1 mg nicorandil, and then returned to the baseline level within 3 m in. Neither arrhythmias nor conduction disturbances were observed. The se results indicate that dilatation of the epicardial coronary artery was achieved with intracoronary nicorandil in a dose-dependent manner (up to 1 mg over 1 min) without any adverse effects in man, and the di latory effect on coronary resistance vessels was of short duration.