A review of the antihypertensive effects of felodipine alone or in combination.

Felodipine is a dihydropyridine that blocks the slow entry channel for calcium. It is highly vascular selective and reduces blood pressure (BP) by dilatation of peripheral arterioles. It reduces BP in mild, moderate, and severe hypertension, and the fall in BP depends upon the initial level. It has been compared with a variety of other drugs as monotherapy or as add-on therapy. In these studies, felodipine (10-40 mg/day) has caused a similar or greater fall in BP and a similar or greater percentage of patients have achieved a diastolic BP less than or equal to 90 mm Hg. The plain tablet of felodipine needs to be given twice a day but an extended-release form can be given once daily. Some patients respond to 5 mg/day and most patients respond to a daily dose of 20 mg or less. The adverse effects are few except for a constellation of symptoms related to the vasodilator ability of the drug. These include palpitations, flushing, fatigue, dizziness, and headaches. These occur, if at all, usually within the first 2 weeks and diminish as the drug is continued. They can be limited by starting on a small dose of felodipine (5 mg/day). People who have these adverse effects usually have a good response to the drug. Another adverse effect, which is the most frequent reason for drug withdrawal, is ankle edema. This is more common on the higher doses of the drug. It is due to dilatation of the precapillary resistance vessels rather than sodium and water retention. Felodipine is a useful and effective antihypertensive drug and can be used as monotherapy or added to other antihypertensive drugs. It is effective in people with all grades of hypertension.