Comparison of the antianginal efficacy of isosorbide dinitrate (ISDN) 40 mg and verapamil 120 mg three times daily in the acute trial and following two-week treatment.

Fourteen male patients with exertion-related angina pectoris and reproducible ST-segment depression on stress testing were each treated with isosorbide dinitrate (ISDN) 40 mg three times daily, verapamil 120 mg three times daily and placebo three times daily for two weeks according to a double-blind cross-over protocol. The mean improvement of exercise-induced ST-segment depression amounted to 73% on the first day of ISDN treatment (P less than 0.001) and to 54% following acute administration of verapamil (P less than 0.001). On the last day of continuous treatment, the antianginal efficacy of ISDN was somewhat mitigated (reduction of ST-segment depression: 54%; P less than 0.001), while the effect of verapamil remained unchanged (55%, P less than 0.001). The double product (heart rate x systolic blood pressure) at the end of stress testing decreased most pronouncedly on day 1 of ISDN treatment (-21%; P less than 0.01). On chronic testing, both drugs similarly influenced this parameter: 10-11% (P less than 0.05). The mean global ejection fraction (EF) assessed by gated blood pool scintigraphy on day 13 showed a stress-induced fall from 49 to 44% (P less than 0.05) after the administration of placebo. The respective values with ISDN were 53% at rest and 52% on exercise (n.s.), and after giving verapamil 50% and 47% (n.s.). Thus, ISDN 40 mg and verapamil 120 mg displayed beneficial anti-ischaemic effects in patients with stable exertion-related angina pectoris after acute and chronic administration. The efficacy of ISDN declined somewhat in the course of the two-week treatment, whereas that of verapamil remained unchanged. Beneficial effects of both drugs were also demonstrated with regard to the rate-pressure product. Isosorbide dinitrate 40 mg and verapamil 120 mg administered three times daily can be recommended for the acute and chronic therapy of patients with stable angina.