CLINICAL INTEREST OF ONCE-DAILY FELODIPINE EXTENDED-RELEASE IN PATIENTS WITH MIXED AND EXERTIONAL ANGINA - RESULTS OF A DOUBLE-BLIND CROSSOVER STUDY VERSUS AMLODIPINE

24 patients with mixed or exertional angina pectoris were enrolled in a double-blind crossover clinical study to compare the efficacy and safety of felodipine extended-release (ER) 10mg once daily versus amlodipine 10mg once daily. Admission criteria did not restrict patient selection according to exercise endurance. The crossover treatment with two 4-week phases started after washout of all antianginal drugs except sublingual nitrates. Maximal multistage exercise tests were performed before initial administration at baseline and 23 hours after the last dose of each of the 2 study drugs. Two patients dropped out, so that efficacy could be evaluated on an intention-to-treat basis in 22 patients (15 with mixed and 7 with exertional angina). At baseline the ischaemic threshold (time to onset of ST depression 2 1 mm) was high, with a mean of 485.3 +/- 174.8 seconds (n = 22, range 180 to 840 seconds). After 4 weeks of treatment, time to test termination showed an increase with both drugs, which attained statistical significance only with felodipine ER (n = 22, + 9.03% : p<0.05). The duration of ischaemia showed a decrease that was more evident with felodipine ER (n = 17, -31.19%) than with amlodipine in = 18, -16.70%), without attaining statistical significance in either case. The significant decrease in maximal ST depression was more evident with felodipine ER (n = 17, -27.72%; p<0.001) than with amlodipine (n = 18, -19.12%: p<0.011. Furthermore, the increase in the time to onset of angina attained statistical significance with felodipine ER (n = 7, + 34.25%; p<0.05) and not with amlodipine (n = 10, + 20.72%). The decrease in the duration of angina also attained statistical significance with felodipine ER (n = 7, -24.34%; p<0.05) and not with amlodipine (n = 10, -23.58%). Adverse reactions occurred with felodipine ER in 2 of 23 (8.3% cases and with amlodipine in 6 of 24 (25%) cases. The most frequent adverse reaction was mild to moderate peripheral oedema that occurred only during treatment with amlodipine (16.7% cases). The possible pharmacological rationale for the better therapeutic results obtained with felodipine ER is discussed by considering both its efficacy and safety.