[Effect of renal insufficiency on the pharmacokinetics of captopril and converting enzyme inhibition in the hypertensive patient].

The influence of renal insufficiency (RI) on the pharmacokinetics of captopril (1 mg/kg, orally) and on the kinetics of the induced converting enzyme inhibition (CEI) was investigated in three groups of hypertensive patients: without RI (n = 10, plasma creatinine less than 100 mumol/l), with moderate RI (MRI) (n = 10,200 less than creatinine less than 400 mumol/l) and with severe RI (SRI) (n = 8, creatinine greater than 500 mumol/l). Captopril pharmacokinetic parameters were not modified by RI, with the exception of elimination half-life which was lengthened, but relative bioavailability of the drug was not modified. In contrast, captopril-induced CEI was strongly potentiated in patients with RI, an effect correlated with plasma creatinine values. This apparent discrepancy between the lack of modification in captopril plasma bioavailability and the prolongation of its biological effects can probably be accounted for by a decreased elimination and/or an increased formation of captopril metabolites during RI.