Pharmacokinetic and clinical studies with carfecillin.

The pharmacokinetics of carfecillin (Carbenicillin-phenyl-ester) were studied in 10 healthy subjects, in 5 patients with hepatic cirrhosis and in 5 cases of renal insufficiency. In healthy subjects maximal carbenicillin serum levels attained by therapeutic doses were about 20 microgram/ml; concentrations in the urine surpassed 1000 mu/ml. The phenol moiety was detectable as free phenol in sera (less than 1 microgram/ml) and urine (less than 3 microgram/ml), but its major part was transformed to glucuronide and sulphate conjugates. Pharmacokinetics were not altered significantly by hepatic lesion. In renal insufficiency, serum levels of both carbenicillin and conjugated phenol were higher and their decrease delayed, while urine concentration was low. Carfecillin treatment was successful in 20 out of 30 patients with UTI.