Endurance testing for evaluation of antianginal therapy with amlodipine, a calcium channel blocking agent

Abstract

The utility of using an endurance test as well as a maximal exercise test to assess the effect of amlodipine, a dihyriropyridine calcium antagonist, was evaluated in 16 patients with angina pectoris. Amlodipine, 10 mg/day, was compared with placebo in a double blind crossover study. After a 2 week single blind placebo period, patients entered a double blind crossover phase alternating between 4 weeks of placebo and 4 weeks of amlodipine. The two 4 week periods were separated by a 1 week single blind placebo washout period. The efficacy of drug therapy was assessed by frequency of angina, nitroglycerin consumption, peak oxygen consumption during a maximal treadmill exercise test and endurance time during a separate exercise test performed at 70% of the peak work capacity determined before randomization.There was a reduction in angina frequency during the double blind placebo and amlodipine studies (single blind placebo 14 ± 2 episodes'2 weeks, double Mind placebo 7 ± 2 episodes/2 weeks [p < 0.0051, amlodipine 6 ± 3 episodes/ 2 weeks, [p < 0.005]), whereas nitroglycerin consumption was reduced with amlodipine (single blind placebo 12 ± 4 tablets/2 weeks, double blind placebo 8 ± 3 tablets/2 weeks, amlodipine 5 ± 3 tablets/2 weeks [p < 0.011]). Amlodipine produced a significant increase in peak oxygen consumption (single blind placebo 18.7 ± 1.1 ml/kg per min, double blind placebo 18.2 ± 1.8 ml/kg per min, amlodipine 20.4 ± 1.6 ml/kg per min [p < 0.05]) and endurance time (single blind placebo 15.2 ± 1.5 min, double blind placebo 15.8 ± 2.1 min, amlodipine 20.2 ± 2.5 min [p < 0.005]). The changes in endurance time were independent of changes in peak oxygen consumption.It is concluded that the endurance exercise test and the maximal exercise test are complementary in evaluating the efficacy of antianginal therapy, but the endurance test may be more sensitive for detecting an improvement. Amlodipine significantly improved endurance time and peak oxygen consumption.