Ciprofloxacin concentrations in tonsils following single or multiple administrations.

Penetration of ciprofloxacin into human tonsils was studied in 20 adult humans undergoing tonsilectomy. Ten patients received a single intravenous infusion of 200 mg ciprofloxacin within 15 min (group A) and 14 patients were treated orally for three days with 500 mg ciprofloxacin b.i.d. prior to a preoperative infusion of 200 mg (group B). Ciprofloxacin concentrations in serum and tonsils were determined microbiologically. Mean ciprofloxacin serum concentrations did not differ significantly between both groups. Similarly, mean distribution ratios between tonsils and serum were not dissimilar, being on average 150% irrespective of whether the drug was administered once or repeatedly. Thus, a significant accumulation of ciprofloxacin was not observed either in the intravascular or in the extravascular space.