[Comparative evaluation of ACE inhibitors: which differences are relevant?].
ACE inhibitors are well established in the treatment of arterial hypertension, heart failure and diabetic and/or hypertensive nephropathy with albuminuria. The important trials for the various indications are briefly discussed. In Switzerland 11 ACE inhibitors are available for clinical use, differing mainly in their pharmacokinetic and pharmacodynamic properties. The characteristics of practical relevance regarding oral bioavailability, elimination mechanisms and half-life, as well as the necessary dosage modifications in patients with renal, hepatic and cardiac failure, are presented. All ACE 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 inhibitors are eliminated predominantly through the kidneys. However, benazepril, 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 required only below a creatinine-clearance level of 30 ml/min. These dosage reductions 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 concomitant diuretic treatment added or maintained. Most common adverse effects of ACE inhibitors are hypotension, cough, hyperkalaemia and renal failure. Less frequent adverse effects are angioedema, bone marrow suppression and also foetal damage. Thus, ACE inhibitors are contraindicated in pregnancy.