Safety of the calcium antagonist lacidipine evaluated from a phase III-IV trial database

We reviewed the clinical safety profile of lacidipine with the help of the rather comprehensive datafile of the manufacturer. Although a number of prospective, randomly allocated trials under way at present are investigating the effects of treatment with calcium antagonists on cardiovascular morbidity and mortality, these results are not yet available. Therefore, the present approach may be useful. A fuller account of this work has been published in Blood Pressure.

Since 1985,50 phase III-IV trials have been performed to investigate antihypertensive efficacy in patients with hypertension; 32 were controlled trials with comparison treatment and 18 were open studies of lacidipine treatment. Only data from trials completed before 1 January 1995 are presented here.

In all, 16590 patients were treated with lacidipine; 13419 in open studies and 3171 in double-blind comparative trials. A total of 1810 patients were given active comparative treatment and 451 were given placebo. Altogether, 5124 person-years of data were obtained.

Numbers of both fatal and non-fatal cardiovascular events were estimated. Efficacy (change in blood pressure and heart rate), adverse event rates and drop-out rates were compared for the different treatment regimens.

In all trials, 2-6 mg lacidipine was effective in lowering blood pressure. In the controlled trials, systolic/diastolic blood pressure fell from 166/102 to 144/85 mmHg and the heart rate fell from 75.6 to 74.1 beats/min. The estimated event rate for a possible myocardial infarction in all studies was 5.46/1000 person-years; the fatal (all-cause) event rate was 5.27/1000 person-years and the estimated fatal cardiovascular event rate was 2.93/1000 person-years. There were 21 malignant events during treatment with lacidipine, for all studies yielding a crude incidence of 4.10/1000 person-years. In patients treated with lacidipine, the age-standardized (according to the world population) incidences were 1.49 (men) and 0.79/1000 person-years (women) compared with 2.74 (men) and 2.09/1000 person-years (women) in the European Community in 1990. The overall incidence in the comparative studies of one or more adverse events included 30.3% for lacidipine, 43.8% for other calcium antagonists, 18.7% for diuretics, 48.7% for beta-receptor blockers, 10.4% for angiotensin converting enzyme inhibitors and 15.7% for placebo. The adverse effects of lacidipine were, as expected, headaches, flushing, pedal oedema and palpitations.

Lacidipine proved to be an effective and well tolerated drug in almost 19000 hypertensive patients. It displayed a reasonable adverse profile that was typical of a calcium antagonist of the dihydropyridine group. This analysis has two obvious limitations: (1) it is a retrospective analysis; and (2) the data were obtained from a large cohort of patients, but most were treated with lacidipine for a relatively short period of time. Although we found a lower fatal event rate than that reported by Collins et al., their meta-analysis included 10 times more person-years than our analysis, and therefore our event rate may be less accurate. Further prospective studies are under way at present to determine whether these drugs can produce reductions in atherosclerosis or in the incidence of cardiovascular disease.