Potassium channel openers in myocardial ischaemia: therapeutic potential of nicorandil.

Potassium channel openers or agonists represent a novel new class of compounds in the treatment of a range of cardiovascular disorders, particularly angina pectoris and hypertension. Nicorandil is the only clinically available potassium channel opener with antianginal effects, and with comparable efficacy and tolerability to existing antianginal therapy. It confers benefits through a dual action: opening the mitochondrial KATP channels leading to preconditioning of the myocardium and a nitrate-like effect. Myocardial preconditioning is important in reducing infarct size, severity of stunning and cardiac arrhythmias. These effects make nicorandil a unique antianginal compound that reduces both pre- and after-load and improves coronary blood flow. Comparative and noncomparative studies support the use of nicorandil as monotherapy or in combination with other antianginal therapy for stable angina pectoris. However, large studies are required to confirm its role in the treatment of acute coronary syndromes despite the favourable results from small studies.