An update on the safety of amlodipine.

A previous article on the safety of amlodipine reviewed data from over 4,000 subjects who participated in clinical trials sponsored by Pfizer Central Research. Once-daily amlodipine was shown to be a well-tolerated treatment of hypertension and myocardial ischemia. Although amlodipine is a potent vasodilator, there was a low incidence of side effects such as headache, flushing, and dizziness. Amlodipine was not associated with adverse effects on hematologic or biochemical safety parameters nor on serum cholesterol or triglyceride levels. Amlodipine did not alter electrical conduction in the heart. Amlodipine had a favorable safety profile in comparative trials vs. beta-blockers. The data base of comparative trials vs. other calcium antagonists was small but the toleration of amlodipine was similar to that of verapamil and diltiazem. No data from comparative trials vs. another calcium antagonist of the dihydropyridine class have been available. This article reviews data from recently completed trials vs. nitrendipine and from trials in which amlodipine was used in combination with other agents. Amlodipine was better tolerated than nitrendipine and had a much lower incidence of side effects usually related to vasodilatation. This difference in side-effect profile was especially marked during the first days of treatment. Amlodipine was well tolerated when used in combination with beta-blockers, diuretics, ACE inhibitors, and nitrates. The gradual onset of action and relatively long half-life of amlodipine are the probable cause for the improved toleration in comparison with other dihydropyridines. Besides the low incidence of trivial side effects, increasing clinical experience with amlodipine provides no evidence that amlodipine is a cause of rare but serious adverse effects. It is concluded that amlodipine is an antihypertensive and anti-ischemic agent that has the combined advantages of a good safety profile with once-daily dosage and a smooth onset and long duration of action.