What, if anything, is controversial about calcium antagonists?

Abstract

Recent publications purporting to show that calcium antagonists, when used for the treatment of hypertension or in the post myocardial infarction patient, would paradoxically increase the rate of heart attack and mortality have cast doubts on the safety and efficacy of this drug class. All three studies are retrospective, and have various drawbacks. Specifically, the metaanalysis of Furberg et al is fraught with mistakes, of borderline significance, and based on old data pertaining to short-acting nifedipine only (which should not be given in patients who have suffered an acute heart attack). The case control study of Psaty et al suggested that hypertensive patients who were treated with short-acting verapamil, diltiazem, and nifedipine had an excessive rate of myocardial infarction when compared with patients who were treated with diuretics. Two out of the three calcium antagonists that were used in this study were not approved for the treatment of hypertension by the US Food and Drug Administration. Some patients were taking these drugs only once a day whereas, because of their short duration of action, at least a three or four times daily regimen would be required to achieve an acceptable blood pressure control throughout a 24-h period. The cohort study of Pahor et al suggested distinct differences among various calcium antagonists with regard to survival. Blood pressure was controlled in <40% of all patients, and in some patients blood pressure was never even measured. Recent studies, such as the Prospective Randomized Amlodipine Survival Evaluation (PRAISE), the third Vasolidator-Heart Failure Trial (VHeFT-III), the second Doppler Flow and Echocardiography in Functional Cardiac Insufficiency Assessment of Nisoldipine Therapy (DEFIANT II), the Angina Prognosis Study in Stockholm (APSIS), and the Shanghai Trial of Nifedipine in the Elderly (STONE), attest to the safety and efficacy of the newer long-acting calcium antagonists in patients with a wide spectrum of heart disease. Several ongoing trials including the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) with amlodipine, the International Nifedipine-GITS Study: Intervention as a Goal in Hypertension Treatment (INSIGHT) with nifedipine, the Hypertension. Optimal Treatment study (HOT) with felodipine, the Systolic Hypertension in the Elderly in Europe Trial (SYST-EUR) with nicardipine, the Second Swedish Trial in Old Patients with Hypertension (STOP II) with felodipine, and Nordic Diltiazem Study (NORDIL) with diltiazem, will give us morbidity and mortality data in patients with high blood pressure within the next few years. Until these results are available, we can be confident that the lowering of blood pressure and providing relief of patients with symptomatic angina can be achieved safely and efficiently with the presently available long-acting calcium antagonists.