Efficacy and safety of amlodipine compared with diltiazem in patients with stable angina pectoris

This parallel double-blind study was designed to assess the efficacy and safety of amlodipine once daily and diltiazem twice daily over 12 weeks in patients with stable angina pectoris. Following a I-week run-in period, 61 patients were randomised to receive amlodipine (5 to 10 mg/day) and 58 patients to receive diltiazem slow release (180 to 360 mg/day). The study used standardised bicycle exercise testing as a primary efficacy assessment. Secondary objectives were to evaluate angina attack rate and nitroglycerin tablet consumption. At baseline, the 2 groups were comparable for all clinical parameters except exercise capacity, which was significantly lower for the amlodipine group. Treatment with both drugs improved exercise time, time to angina and total work. The difference between the groups at the end of the trial was not statistically significant. There were no significant differences in blood pressure and heart rate arrest or during exercise between the 2 treatment groups. The reductions in nitroglycerin consumption and angina attacks were the same for both groups. Adverse reactions were reported in 36 patients in the amlodipine group and in 29 patients in the diltiazem group. The difference was not statistically significant. The total number of reported adverse events was significantly higher in the amlodipine group compared with the diltiazem group (p = 0.017). However, most of the adverse events were mild to moderate. Severe events were reported in 6 patients in the amlodipine group and in 8 patients in the diltiazem group. 10 patients in the amlodipine group and 9 in the diltiazem group were withdrawn from treatment, mainly because of lack of efficacy or adverse reactions, In conclusion, the study demonstrated that amlodipine did not differ from diltiazem in terms of efficacy and showed a similar safety profile.