Purpose: Efficacy, tolerability, and optimal doses of felodipine ER (FER) and diltiazem SR (DSR), given as monotherapy, were evaluated in patients with mild or moderate primary hypertension.
Methods: This was a multicenter, double-blind, parallel-group study of 98 hypertensive patients. Following a 4 weeks placebo run-in period, patients were randomized to either FER 5 mg once daily (qd) or DSR 90 mg twice daily (bid). If supine DBP was > 90 mmHg after 2 and 4 weeks treatment, the dose was increased to 10 mg FER qd or 120 mg DSR bid plus 20 mg FER qd or 180 mg DSR bid, respectively. The double-blind treatment lasted 8 weeks.
Results: After 8 weeks FER treatment 70% of the patients responded (DBP < or = 90 mmHg or DBP decrease > or = 10 mmHg) and 50% became normotensive (DBP < or = 90 mmHg); the corresponding figures for DSR were 63% and 37%, respectively. No statistical significant differences in BP reduction and HR were found between the two compounds. HR did not change during the study. Seven patients discontinued due to adverse events (AEs). Five patients received FER and two patients received DSR. The AEs were similar in the two groups and generally mild.
Conclusions: At the highest dose levels of FER and DSR, no further BP reduction was observed, but there was a tendency to report more AEs. Both FER and DSR can be used as first-line therapy in hypertension.