Mechanism of action
Nicorandil induces vascular smooth muscle relaxation by increasing intracellular cyclic guanosine monophosphate (cGMP) levels. Potassium channel opening hyperpolarises vascular cell membrane, causing calcium (Ca2+) ion channels to close and a consequent reduction in intracellular Ca2+ concentration (i.e. indirect calcium antagonism) that results in further smooth muscle relaxation and vasodilatation. Nicorandil is potent vasodilator of the coronary and peripheral vascular beds. Because of its effects in reducing preload and after load, it influences two of the main determinants of oxygen demand without impairing myocardial contractility and thus, by reducing cardiac workload, has a potentially useful role in a number of cardiovascular conditions.