Felodipine compared to prazosin as additional therapy to a β-blocking drug

Felodipine was compared with prazosin in patients with essential hypertension whose blood pressure was not controlled by a β-blocking drug. One hundred patients with a supine diastolic blood pressure ⪖95 mm Hg after 4 weeks or more on a β-blocking drug and placebo were randomly assigned to felodipine or prazosin tablets. The drugs were titrated at 2-week intervals if diastolic BP was ⪖90 mm Hg. Titration steps of felodipine were 5, 10, 20 mg b.i.d. and of prazosin were 1,2,4 mg b.i.d. The fall in blood pressure with felodipine 32/21 mm Hg was greater than the fall with prazosin 16/12 mm Hg (p < 0.001); 36 patients achieved a diastolic blood pressure of <90 mm Hg with felodipine, which was a significantly greater number than the 20 patients who obtained such a level with prazosin (p < 0.01). Both drugs were well tolerated, but more patients complained of vascular type side effects (flushing, peripheral edema) with felodipine than with prazosin. There was significant weight gain with prazosin but not with felodipine. Felodipine was shown to be a well-tolerated, effective antihypertensive agent when used with a β-blocking drug and to be suitable for people with hypertension who fail to be controlled with a β-blocking drug.