ANTIANGINAL RESPONSE TO ONCE-DAILY DILTIAZEM CD IN PATIENTS RECEIVINGCONCOMITANT BETA-BLOCKERS, LONG-ACTING NITRATES, OR BOTH

Study Objective. To determine the safety and efficacy of diltiazem CD 180 mg administered once/day in patients with chronic stable angina in adequately controlled with P-blockers, long-acting nitrates, or both. Design. Multicenter, randomized, double-blind, placebo-controlled, par allel-roup trial. Setting. Medical clinics in the private and academic sectors. Patients. Of 172 patients, 170 completed the 2-week double-b lind treatment period. Interventions. Patients received either diltiaz em CD 180 mg or placebo once/day in combination with existing antiangi nal therapy. Measurements and Main Results. The time to termination of exercise tolerance testing, 24 hours after the dose increased signifi cantly in the diltiazem CD group (37.2 sec) compared with the placebo group (21.3 sec, p = 0.0438). Time to onset of angina during exercise testing also increased (57.6 vs 35.0 sec, respectively, p = 0.0324), a s did time to moderate angina (37.5 vs 20.6 sec, respectively, p = 0.0 354). The rates of total angina attacks and of angina attacks on exert ion were significantly reduced in the diltiazem CD group versus placeb o (p < 0.05). Significant reductions in systolic and diastolic blood p ressures and heart rate-blood pressure product measured at rest, subma ximum exercise, and exercise termination were observed in diltiazem CD -treated patients compared with placebo (p < 0.05). The frequency of t reatment-related adverse events was identical in the two groups, 15.1% . Conclusion. Diltiazem CD 180 mg once/day is an effective, safe, and beneficial initial dosage when added to existing antianginal therapy.