Until recently, only three calcium channel antagonists--verapamil, diltiazem and 
nifedipine--were available for managing cardiovascular disorders such as 
hypertension and ischemic heart disease. In the past few years, however, several 
dihydropyridine calcium channel antagonists, including nicardipine, isradipine, 
felodipine, nimodipine, and amlodipine, have been marketed. Others are currently 
awaiting FDA approval. In addition, bepridil, which belongs to a new class of 
calcium channel antagonists, has recently been marketed for refractory angina 
pectoris. Clinical uses of calcium channel antagonists have been expanded since 
the 1970s to include management of cardiovascular disorders such as 
supraventricular arrhythmias, CHF secondary to diastolic dysfunction, and 
myocardial reinfarction in selected patients. Calcium channel antagonists are 
also being investigated for prevention of atherosclerosis. Calcium channel 
antagonists are a heterogeneous group of pharmacologic agents. Differences in 
tissue selectivity are largely responsible for the variations in hemodynamic and 
electrophysiologic properties of these agents. Thus, their clinical uses and 
side effect profiles differ. These differences must be taken into consideration 
in the selection of the most appropriate agent for a specific indication. 
Potential advantages of some of the newer dihydropyridine calcium channel 
antagonists include less frequent dosing (amlodipine and isradipine) and little 
or no negative inotropic effect (nicardipine, felodipine, amlodipine, 
isradipine) compared with the prototype calcium channel antagonists. Additional 
clinical experience with these newer agents is required, however, before their 
role in the management of cardiovascular disorders can be fully delineated. The 
availability of sustained-release formulations of verapamil, diltiazem, 
nifedipine, felodipine, and nicardipine, as well as the recent marketing of 
calcium channel antagonists with relatively long half-lives (amlodipine and 
isradipine), makes once- or twice-daily dosing possible with most calcium 
channel blockers. However, selection of a particular agent will depend on 
several factors, including clinical efficacy, side effect profile, cost, and 
patient characteristics such as concomitant disease states and baseline 
hemodynamic status.