Drug interactions with the calcium-entry blockers.

The increasing use of the calcium-entry blockers has led to an enhanced potential for drug interactions with a variety of different drugs. Interactions with cardiovascular agents are of great concern because of the consequences of synergistic negative dromotropism or inotropism. We therefore assessed the concomitant use of calcium-entry blockers and cardiac glycosides, beta-blockers, antiarrhythmic agents, and other chemical types of calcium-entry blockers from a standpoint of clinical relevance. We also evaluated reported drug interactions with H2-receptor antagonists, anticonvulsants, lithium carbonate, general anesthetics, cytostatic drugs, rifampin, and sulfinpyrazone with regard to clinical implications, along with the modification of calcium-entry blocker dose for concurrent social drug use, such as cigarette smoking and ethanol intake. Although a myriad of potential drug interactions exists for these agents, combination therapy is still a reasonable alternative if doses are adjusted appropriately.