Penetration of clindamycin and metronidazole into the appendix and peritoneal fluid in children.

Thirty-one children underwent appendectomy following administration of a single i.v. dose of clindamycin 10 mg/kg or metronidazole 7.5 mg/kg. The serum levels of the antibiotics at that time were comparable, but the tissue concentration of clindamycin in the appendix (mean 7.23 micrograms/g) exceeded that of metronidazole (mean 2.27 micrograms/g). The concurrent mean concentration of metronidazole in peritoneal fluid (14.26 micrograms/ml) was higher than that of clindamycin (7.72 micrograms/ml).