1 Perindopril is a prodrug which is hydrolysed in vivo to the active metabolite perindoprilat, an angiotensin-converting enzyme inhibitor. Perindoprilat glucuronide is also found in plasma. 2 The pharmacokinetics of perindopril and its metabolites were studied after administration of a single 4 mg dose to hypertensive patients with various degrees of renal failure. 3 The absorption and elimination of perindopril were not influenced by the degree of renal failure. 4 The mean area under the serum concentration-time curve of the active metabolite perindoprilat increased from 93 ng ml-1 h in subjects with normal renal function to 1106 ng ml-1 in patients with severe renal failure, whereas its half-life varied from 5.0 to 27.4 h. 5 In the same subjects, the mean area under the curve of perindoprilat glucuronide increased from 78 to 513 ng ml-1 h, while its half-life varied from 1.8 h to 7.7 h. 6 Perindopril, perindoprilat, and perindoprilat glucuronide were dialysable. 7 The extent and duration of serum angiotensin-converting enzyme inhibition was augmented in renal failure. The mean area under the inhibition time curve (extrapolated to infinity) increased from 2490%.h in subjects with normal renal function to 42241 %.h in patients with severe renal impairment. The half-life of inhibition varied from 12.1 h to 100.4 h. This effect of renal failure on the pharmacodynamics of perindoprilat was more pronounced than its influence on perindoprilat kinetics. 8 In view of the important influence of renal impairment on the elimination and action of the active substance perindoprilat, a dosage reduction of perindopril is proposed in in patients with renal failure.(ABSTRACT TRUNCATED AT 250 WORDS)