Clinical equivalence of two tablet formulations of felodipine. A placebo-controlled study of 24-hour blood pressure control and tolerability.

OBJECTIVE

This study was performed to assess whether a new formulation of felodipine extended release (FER) tablets with a 9 mm diameter is similar to the presently used 11 mm diameter FER formulation with respect to antihypertensive effect and tolerability in patients with essential hypertension. A randomised, double-blind, placebo controlled, three-way cross-over study design was used.

PATIENTS

Twenty-four patients with a supine diastolic blood pressure (DBP) of 95-115 mmHg after a 4-week placebo run-in period were given FER 5 mg 9 mm tablets, FER 5 mg 11 mm tablets and placebo in randomised order. The tablets were given once daily and each double-blind treatment period lasted for two weeks.

METHODS

Twenty-four hour ambulatory blood pressure monitoring was performed at the end of each treatment period. The primary effect variable was mean DBP over 24 hours. Nineteen patients had 24-hour blood pressure data valid for analysis using an analysis of variance with patient, treatment, period and carry-over as factors.

RESULTS

Both formulations of FER 5 mg tablets significantly reduced the mean 24-hour DBP compared to placebo. The 9 and 11 mm tablets resulted in, on average, 4.7 and 3.4 mmHg lower mean 24-hour DBP than placebo. There was, however, no significant difference between the two different FER formulations. Both FER formulations were well tolerated and similar to placebo in this respect.

CONCLUSION

Both FER 5 mg tablet formulations (9 and 11 mm diameter), given once daily, were clinically equivalent with respect to antihypertensive effect and tolerability in patients with mild to moderate essential hypertension.