The evolving role of calcium channel blockers in the treatment of angina pectoris: focus on felodipine.

Calcium channel blockers are used extensively in the treatment of the three major anginal syndromes. In the treatment of Prinzmetal's angina, their antivasospastic properties account for their therapeutic effectiveness. Calcium channel blockers are drugs of first choice in this syndrome. In chronic stable angina, calcium channel blockers may be used as monotherapy or in combination with beta-blockers and/or nitrates. In patients with unstable angina, reduction in the incidence of ischemic episodes produced by calcium channel blockers is well documented. Recent data suggest that calcium channel blockers should generally be used in combination with beta-blockers, nitrates and antithrombotic agents. Patients with ischemic heart disease often exhibit reduced ventricular function. All of the first generation calcium channel blockers exacerbate symptoms in patients with established heart failure and may precipitate heart failure, particularly when combined with beta-blockers. Second generation vascular-selective dihydropyridines have been introduced recently. Vascular selectivity determines the drug's degree of negative inotropic effect. Felodipine is one of the most vascular selective of the available dihydropyridines and has no negative inotropic effects at clinically administered doses. In a long term study, felodipine, 20 mg/day, abolished symptoms and chronic ischemic episodes in 81% of treated subjects with Prinzmetal's angina. In patients with stable angina, felodipine has been found to be effective either as monotherapy or in combination with beta-blockers. In patients with known or suspected ventricular dysfunction, vascular-selective dihydropyridines such as felodipine offer advantages over the nonselective calcium channel blockers, particularly in patients receiving beta-blockers.