Since
labetalol was first reviewed in the Journal (1978), its scope of
therapeutic use has expanded and become better defined.
Labetalol is an
adrenoceptor blocking
drug with combined alpha- and beta-blocking properties. These result in a more favourable haemodynamic profile for
labetalol compared with 'pure' beta-blockers or pure alpha-blockers, but also contribute to a wider range, but not an overall increased incidence, of adverse effects. The
drug is effective and well-tolerated in patients with all grades of
hypertension, but is of particular value in special subgroups such as Black patients, the elderly and patients with
renal hypertension. While comparative studies are not extensive, available data show that the
drug reduces blood pressure to a similar extent, and in a similar proportion of patients, as 'pure' beta-blockers such as
propranolol, pure alpha-blockers such as
prazosin,
calcium antagonists (
nifedipine,
verapamil), and centrally acting drugs (
clonidine and
methyldopa).
Labetalol is very effective in hypertensive pregnant women and in
hypertensive crises, where it provides good control of blood pressure without serious adverse effects, and where few therapeutic options exist. Few controlled studies have investigated the use of
labetalol in deliberate induction of
hypotension or prevention of
hypertension during anaesthesia, and also in patients with ischaemic
heart disease. However, available evidence suggests a role for
labetalol in these indications and further studies should aid in clarification of its efficacy in these areas. Thus, with its broad scope of
therapeutic use in
hypertension labetalol remains an important therapeutic option, and the
drug may well find an additional place in the treatment of myocardial ischaemia if further evidence confirms encouraging preliminary findings.