Pharmacokinetics of temocillin (BRL 17421) in subjects with normal and impaired renal function

The pharmacokinetics of temocillin were investigated in five normal subjects and in 20 uraemic patients. Normal subjects were given single intravenous doses of 3.75, 7.5 and 15 mg/kg of temocillin and a single intramuscular dose of 7.5 mg/kg. Patients with renal impairment were given 7.5 mg/kg of the antibiotic intravenously. A three-compartment open model was used to calculate kinetic data after iv administration. Pharmacokinetic parameters of temocillin were similar both for the three iv doses and for the im dose. The terminal serum half-lives (T1/2 beta) averaged 4.75-5.88 h. The central distribution volume (Vc) and the apparent volume of distribution (Vd area) were 0.093-0.111 and 0.268-0.303 l/kg, respectively. Renal and total body clearances were within 27.4-34.1 and 40.2-47.8 ml/min/1.73 m2, respectively. 67.4-71.5% of the dose was recovered unchanged in urine over 24 h. Intramuscular dosing of 7.5 mg/kg gave a mean peak level of 26.71 mg/l at 1.67 h. In uraemic patients, similar maximum serum concentrations were found after a single 7.5 mg/kg iv dose. The terminal half-life increased according to the degree of renal failure, from 5 h in normal subjects to about 30 h in severe uraemic patients. Renal impairment did not significantly modify Vd area, fractional clearance (Cr/GFR) and non renal clearance. 65.2% of the antibiotic was removed during haemodialysis. Dosage adjustments of temocillin in uraemic patients are proposed.