Pharmacokinetics and bactericidal activity of sultamicillin in infants and children.

The pharmacokinetics of sultamicillin and ampicillin suspensions were studied in 20 infants and children 8 months to 69 months of age (mean age, 27 months). Mean peak plasma concentrations of ampicillin and sulbactam occurred at 90 minutes after administration of 42.5 mg of sultamicillin (25 mg of ampicillin/kg and 17.5 mg of sulbactam/kg) per kg to fasting and non-fasting patients. Co-administration of milk usually resulted in higher concentrations of ampicillin and sulbactam, however, the differences in the AUC values between the fasting and fed groups were not statistically significant. Sultamicillin and ampicillin were administered in cross-over fashion to ten children. Plasma concentrations of ampicillin after 42.5 mg of sultamicillin per kg were greater at 20, 40, and 60 min than those after 25 mg of ampicillin per kg alone and the AUC was 39% larger in subjects who received sultamicillin than in those who received ampicillin. Plasma bactericidal activity against a non-beta-lactamase producing Haemophilus influenzae strain was similar for children who were given sultamicillin or ampicillin. Against a beta-lactamase-producing Haemophilus strain the median bactericidal titres were 1:8 at 40, 60 and 90 min after sultamicillin and less than 1:2 at the same intervals after ampicillin.