The influence of renal function on the elimination kinetics of sulbenicillin in man

Serum concentration and urinary excretion following a single i.v. dose of 1 g Sulbenicillin (SB) have been studied in 13 subjects with different degrees of renal insufficiency and 4 control subjects. With normal GFR, serum half-life averages 27 min, with GFR between 45 and 14 ml/min, 1,5 hours, with GFR below 8-10 ml/min, 4,6 hours (maximum 7 hours). The usually recommended dosage schedule is 1 g every 6 hours. Only when GFR falls below 8-10 ml/min, the interval between doses must be changed; 1 g every 8-12 hours should be given under these conditions. However, in cases of severe extrarenal or urinary tract infections due to antibiotic-resistant strains of E. coli, Ps. aeruginosa, Pr. morganii, a first dose of 2-4 g SB should be given, followed by maintenance half-doses (1-2 g SB) every half-life.