Dihydropyridine calcium channel blockers: basic pharmacological similarities but fundamental therapeutic differences.

Recent trials indicate that treatment with calcium channel blockers (CCBs) reduces cardiovascular morbidity and mortality in hypertensive patients (including those with significant coronary artery disease). Since the fundamental mechanism of action of all CCBs is the same, it might be assumed that the findings of these outcome studies can be generalized to all types of CCB. However, in the light of the well-recognized clinical pharmacological differences between the 'rate-limiting' agents, verapamil and diltiazem, and the dihydropyridine group of CCBs, this must be considered to be a misconception. Less well-recognized, and often ignored, are the significant differences between agents within the dihydropyridine group. These differences translate to distinct differences in the therapeutic profiles and may well translate into differences in outcome during long-term treatment. Thus, the differences in pharmacokinetic, pharmacodynamic and therapeutic profiles make it clear that caution should be exercised in assuming that all dihydropyridine CCBs licensed for once-daily administration are equivalent in terms of their durations of action and overall antihypertensive efficacy.