SAFETY OF LONG-ACTING DIHYDROPYRIDINE CALCIUM-CHANNEL BLOCKERS IN HYPERTENSIVE PATIENTS

Issues raised recently concerning the safety of calcium channel blocke rs (CCBs) prompted an analysis of the occurrence of cardiovascular eve nts and death in the Pfizer Inc. hypertension clinical trial databases for amlodipine (Norvasc) and nifedipine in the gastrointestinal thera peutic system (GITS) formulation (Procardia XL). Prospectively defined analyses of data from comparative and noncomparative trials of amlodi pine and nifedipine GITS were conducted. Outcome measures included car diovascular and noncardiovascular deaths, and adverse cardiovascular e vents including new/worsened angina, myocardial infarction (MI), serio us arrhythmia, stroke, congestive heart failure, and bleeding. Among a ll amlodipine-treated patients (n = 32,920), the incidence rates for a ll-cause death, MI, and new/worsened angina were 3.0, 3.3, and 1.6/1,0 00 patient-years of exposure, respectively. Among those in comparative trials alone (n = 4,126), the all-cause death rate was 4.1/1,000 pati ent-years, which was comparable to that of other non-CCB agents and si gnificantly less than that of other CCBs (23.8/1,000 patient-years, p = 0.015), although the difference in rates represents only 2 deaths. A mong all nifedipine-GITS-treated patients (n = 2,645), the rate of all -cause death was 4.1/1,000 patient-years, of MI 6.5/1,000 patient-year s, and of new/ worsened angina 5.7/1,000 patient-years. The incidence rates for MI and other cardiac events were low in these hypertension t rials, and did not differ among treatment groups in either the amlodip ine or nifedipine GITS comparative analyses. In the clinical trial dat abases analyzed, there is no signal suggesting excessive risk of death or cardiovascular events for hypertensive patients treated with amlod ipine or nifedipine GITS. (C) 1998 by Excerpta Medica, Inc.