Comparative assessment of ACE inhibitors: what differences are relevant?

ACE inhibitors are well established in the treatment of arterial hypertensi on, heart failure and diabetic and/or hypertensive nephropathy with albumin uria. The important trials for the various indications are briefly discusse d. In Switzerland 11 ACE inhibitors are available for clinical use, differi ng mainly in their pharmacokinetic and pharmacodynamic properties. The char acteristics of practical relevance regarding oral bioavailability, eliminat ion mechanisms and half-lift, as well as the necessary dosage modifications in patients with renal, hepatic and cardiac failure, are presented. All AC E inhibitors except captopril and lisinopril are administered as prodrugs. The bioavailability among ACE inhibitors varies widely with a range from 11 % (trandolapril) to more than 60% (captopril). The great majority of ACE in hibitors are eliminated predominantly through the kidneys. However, benazep ril, fosinopril, ramipril, spirapril and trandolapril also have a hepatic ( metabolic) route of elimination. Since half-life varies from 1 h (captopril ) to 30 h (spirapril) we drew up, for simplicity, a table of 3 groups with short, medium and long t1/2. In renal insufficiency dose adjustment is requ ired only below a creatinine-clearance level of 30 ml/min. These dosage red uctions are not required in liver diseases, but renally excreted drugs such as lisinopril should be preferred. Treatment with ACE inhibitors in severe heart failure should be initiated carefully, with low doses and concomitan t diuretic treatment added or maintained. Most common adverse effects of AC E inhibitors are hypotension, cough, hyperkalaemia and renal failure. Less frequent adverse effects are angioedema, bone marrow suppression and also f oetal damage. Thus, ACE inhibitors are contraindicated in pregnancy.