Nicorandil: A potassium channel opening drug for treatment of ischemic heart disease

Nicorandil is the first oral potassium channel activating drug to be used for the treatment of symptomatic coronary artery disease. It appears to relax vascular smooth muscle through membrane hyperpolarization via increased transmembrane potassium conductance and, like nitrates, through an increase in intracellular cyclic GMP. In addition, nicorandil, in a nitrate-like manner, dilates normal and stenotic coronary arteries and reduces both ventricular preload and afterload. In contrast to nitrates, however, nicorandil does not appear to cause tolerance with long-term administration. In placebo and comparison clinical trials, nicorandil has demonstrated some efficacy and safety in patients with both stable and vasospastic angina pectoris, and it was found to be a myocardial protective agent in animal studies. The antianginal activity of nicorandil, however, is relatively short lived after dosing, which will necessitate the development of extended release formulations of the drug.