Clinical profile of nicorandil: an overview of its hemodynamic properties and therapeutic efficacy

Abstract

Nicorandil is a new vasodilator agent. Efficacy and safety of nicorandil in the treatment of angina pectoris have been evaluated through an extensive clinical program with a total of 1,680 patients who received the product. Results of hemodynamic studies provide clear evidence of the vasodilatory effect of nicorandil. In a population of patients with normal left ventricular function, a reduction in preload was apparent from a decrease in left ventricular end-diastolic pressure from 7.4 +/- 1.7 to -3.2 +/- 1.5 mm Hg. Furthermore, nicorandil produced marked reductions in total peripheral resistance (19%) and aortic blood pressures with decreases in systolic pressure of 34% and in diastolic pressure of 21%. At antianginal doses, nicorandil has a coronary vasodilating effect as well as a balanced peripheral action that leads to decreases in both preload and afterload. Therefore, nicorandil affects two of the main hemodynamic determinants of oxygen demand without impairing myocardial contractility or atrioventricular conduction. In addition, its strong spasmolytic activity is of particular interest when dynamic coronary obstruction is considered. Nicorandil clearly has demonstrated K(+)-channel-opening activity. In addition, the range of plasma concentrations in humans at therapeutic doses is similar to that of experimental models in which the K(+)-channel activity has been determined. This mechanism of action may explain the different hemodynamic profiles of nicorandil and nitrates in humans. Nicorandil is an effective and potent antianginal agent at a dose of 10-40 mg, which in monotherapy controls 69-80% of patients with stable chronic angina. Comparative trials have shown that the efficacy of nicorandil compares with that of drugs from the main classes of antianginal drugs--beta-blockers (atenolol, propranolol) and a Ca2+ antagonist (diltiazem). Patients treated for as long as 3 months or 1 year have shown sustained efficacy with no evidence of development of tolerance to the drug. The long duration of action allows effective treatment with a well-tolerated b.i.d. regimen. At the recommended doses, the main side effects were limited to headaches. They usually occurred early in the course of treatment and can be diminished by a progressive titration. From the large safety data base, there is no evidence that nicorandil induced exacerbation of myocardial ischemia or abrupt withdrawal syndrome. Nicorandil does not adversely affect the lipid profile or the glucose level. As an antianginal drug with a novel mechanism of action, nicorandil provides a useful alternative to existing antianginal agents in the long-term management of patients with angina pectoris.