THERAPY

Enalapril's place in antihypertensive therapy defined

Enalapril, one of the first ACE inhibitors to be marketed, is now established as an effective agent in hypertensive patients. It effectively lowers BP in all grades of essential and renovascular hypertension. It is at least as effective as other established and newer ACE inhibitors and members of other antihypertensive drug classes such as diuretics, ,a-blockers, calcium antagonists and a-blockers. For a comparable reduction in diastolic BP, enalapril produces a greater reduction in systolic BP than ,a-blockers. Most patients who do not respond adequately to enalapril alone usually achieve normalisation of BP by the addition of a thiazide diuretic; rarely, a third agent from another drug class may be required. Stepped-care therapy starting with enalapril offers certain advantages compared with other 'triple therapy' regimens: occasionally more effective BP control, less need for addition of other agents, improved compliance from simplified dosage regimens and decreased daily tablet consumption, and fewer side effects (particulary bradycardia and hypokalaemia).

Enalapril appears to offer certain specific advantages over other drug classes, i.e. lack of unwanted metabolic effects, and improvement in renal function in most patients with pre-existing mild to moderate impairment.

The need to individualise antihypertensive therapy, according to patient response to different pharmacological classes, is increasingly becoming evident. Identification of groups in which enalapril is particulary effective is useful in maximising the expected response. Black patients are less likely to respond adequately to monotherapy with enalapril or other ACE inhibitors than White patients, a similar situation to that seen with ,a-blockers, whereas this difference is not seen with other antihypertensive drug classes. Enalapril appears to be a logical first-line option in hypertensive diabetic patients, because it provides appropriate BP control with no loss in metabolic control of diabetes. Moveover, those patients with incipient or overt diabetic nephropathy show a marked decrease in urinary protein excretion during enalapril treatment. This anti protein uric effect is also seen in normotensive diabetic patients. However, before the use of enalapril could be justified in normotensive diabetic patients, more studies are required to define the specific nature of the anti protein uric effect, which appears to be unrelated to systemic BP reduction.

Enalapril is well tolerated during long term administration. The most frequent adverse effect limiting continued enalapril treatment is the now well recognised ACE inhibitor-induced cough. Serious adverse events are rare. The tolerability profile of enalapril appears particulary favourable compared with other antihypertensive drug classes for 2 reasons: the first is the lack of adverse vasodilatory, CNS or metabolic effects, and the second is the lack of some contraindications which are commonlv associated ISSN 0156·2703/92/0516-0019/$1.00/0 © AdislnlematiollallJd

with other drug classes. Compared with other ACE inhibitors, enalapril is at least as well tolerated as the newer agents (e.g. lisinopril, ramipril, quinapril, benazepril, perindopril). Enalapril is often well tolerated in some patients who exhibit certain adverse effects with captopril, and the reverse has also been reported.

The background of experience with enalapril seems to justify its increasing worldwide acceptance as a logical first-line option in patients with hypertension. Torlrl P"- Goa KI Fnalapril. "- reappraisal of its pharmacology and therapeutic use in hyper[t:n,ion. Drug, 43: 346-381. Mar 1992

INPHARMA® 16 May 1992

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