Effectiveness of diltiazem for chronic stable angina pectoris.

Diltiazem can be effective monotherapy for most patients with chronic stable angina pectoris. The exact mechanism(s) of action of diltiazem for producing a salutary effect in patients with angina pectoris is unknown, but probably involves a reduction in myocardial oxygen demand and an increase in supply via coronary artery dilatation. Administration of less than or equal to 240 mg/day in divided doses uncommonly produces any side effects. Doses of 360 mg/day may be required in some patients. The major adverse effect of high dose therapy is mild pedal oedema. Caution concerning orthostatic hypotension is advised when high dose diltiazem is combined with nitrate therapy or used in patients with poor left ventricular function. Also, diltiazem may potentiate bradycardia or atrio-ventricular block, especially when combined with digitalis preparations or beta-blockers. However, in patients with severe angina, diltiazem may be additive to nitrate and/or beta-blocker therapy.