[Clinical pharmacology of ACE inhibitors]

The main effect of the ACE-inhibitors is a reduction of the peripheral resistance and according to that an increase of blood-flow to the organs. Direct effects on the heart are of minor importance. The exact mechanism of action is not fully understood; the main role plays obviously the inhibition of the angiotensin converting enzyme itself; in addition may be effects on the kallikrein-bradykinin-prostaglandin-system are of importance. The pharmacodynamical effects depend on the plasma-concentration and therefore on the pharmacokinetics. These are different with Captopril and Enalapril: Captopril acts directly whereas Enalapril is a "prodrug". With the nowadays used doses Captopril and Enalapril are widely free of side-effects. With the exception of patients with negative sodium-balance (salt-poor diet and/or treatment with diuretics) or patients with renal insufficiency (sometimes increase of creatinine and potassium). In the first group of patients the first dose of ACE-inhibitors should be administered in the evening before going to bed, in the second group creatinine and potassium must be checked 5 to 7 days after an initiation of treatment.