A possible interaction between lithium and diltiazem: case report.

The calcium channel blockers are a group of drugs that have recently become available for the treatment of angina. They act by blocking the entry of calcium into cells during depolarization. Lithium has electrochemical qualities similar to calcium and influences calcium metabolism and calcium transport. The case reported here documents the use of diltiazem in a patient treated with lithium. A possible synergistic drug interaction occurring between diltiazem and lithium is reported.