Clinical Differences Between The Calcium Channel Blocking Agents

Abstract

The clinical differences between the different drugs which have been classified as calcium channel blocking agents are not as yet completely defined. The vast majority of literature which has appeared to date evaluates a single one of these drugs in comparison to placebo or less frequently in comparison to beta blockers. There are only a handful of studies which evaluate two or more of these new drugs in the same patient population. Assuming appropriate dose equivalency (which is not necessarily readily agreed upon), this latter type of study involves the least presumptions about clinical differences between these agents and thus potentially allows direct comparison of their relative efficacy and toxicity. However, the number of such studies is quite limited, the number of patients studied are small and dose equivalence between different agents is not as yet firmly established. Thus, most of the available information for comparing the different calcium channel blocking agents comes from independent studies of one or another of these agents. Such indirect comparisons can reasonably be inferred from studies of single agents when the clinical response appears to be a duplication and/or extension of pharmacologic effects observed in animals and when qualitatively different side effects are noted in the consensus of independent investigations. Table 1 lists the cardiovascular diseases and syndromes for which calcium channel blocking agents have been advocated. In this brief review I will indicate the clinical highlights of few emerging calcium channel blocking agents, emphasing the clinical differences that have been noted when these agents have been used to treat cardiovascular disease and syndromes of major clinical importance.