Safety aspects of treatment with lacidipine--a slow-onset, long-acting calcium antagonist

The aim was to review the clinical safety profile of lacidipine with the help of the rather comprehensive datafile of the manufacturer- a novel approach which may be of some value while awaiting the outcome of calcium antagonist treatment in prospective, randomised trials of cardiovascular morbidity and mortality.

This paper includes data from clinical trials finished before 1 January 1995. Since 1985, 50 phase III-IV trials have been performed investigating antihypertensive efficacy in patients with hypertension; 32 were controlled trials with comparison treatment and 18 were open studies of lacidipine treatment.

In all, 16,590 patients received lacidipine; 13,419 in open studies and 3171 in double blind, comparative trials. Altogether, these patients contributed 5 124 person-years (p.y.). Furthermore, active comparative treatment was given to 1810 patients and placebo to 451.

Both fatal and non-fatal cardiovascular events have been estimated. Efficacy (change in blood pressure and heart rate), adverse event rates, and drop-out rates have been compared for the different treatment regimes. Also the reasons for dropping out of studies have been compared. Adverse effects were also analysed as to their time of occurrence and duration.

Blood pressure was lowered by 2-6 mg lacidipine; in the controlled trials from 166/102 to 144/85 mmHg. Heart rate dropped from 75.6 to 74.1 beats per minute. The estimated event rate for a possible myocardial infarction in all studies was 5.46 per 1000 p.y. The fatal (all causes) event rate was 5.27 per 1000 p.y., and the estimated fatal cardiovascular event rate 2.93 per 1 000 p.y. In one long-term study (48 weeks) comprising 2282 patients (1658 p.y.), the observed fatal (all causes) event rate was 4.2 per 1 000 p.y. The overall incidence in the comparative studies of (one or more) adverse events was: for lacidipine 30.3%, other calcium antagonists 43.8%, diuretics 18.7%, beta-receptor blockers 48.7%, ACE inhibitors 10.4%, and placebo 15.7%. The adverse effects of lacidipine were the expected ones, e.g. headache, flushing, pedal oedema, and palpitations.

When analysing the data on file for lacidipine and some comparatory drugs in almost 19000 hypertensive patients we have found lacidipine to be an effective and well tolerated drug with a reasonable adverse profile typical for a calcium antagonist of the dihydropyridine group. Our study has the obvious limitations of a retrospective analysis of data obtained from a large cohort of patients, most of whom received lacidipine for a relatively short period of time. The present results indicate a lower fatal event rate than previously reported in the actively treated hypertensives in Collins' meta-analyses, comprising ten times more person-years than our analysis. Prospective studies with lacidipine focusing on possible reductions of atherosclerosis as well as incidence of cardiovascular disease are required and are well under way.