Pharmacokinetics in serum and leukocyte exposures of oral azithromycin, 1,500 milligrams, given over a 3- or 5-day period in healthy subjects

The pharmacokinetics in serum and leukocyte (WBC) exposures of 1,500 mg of oral azithromycin administered as 3-day (500 mg/day, days 1 to 3) and 5-day (500 mg on day 1 and 250 mg/day on days 2 to 5) regimens were compared in 12 healthy volunteers. Serum, polymorphonuclear leukocytes, and mononuclear leukocytes were collected over a 12-day period from the start of each regi men. Results of the study indicate that the exposures of serum and both typ es of WBCs were similar with both regimens. Drug concentrations in day 12 W BCs were well above the MICs for all relevant community-acquired respirator y tract pathogens. Terminal half-lives in serum obtained by both regimens w ere essentially equal at 66 h and consistent with past reports. These resul ts indicate that the standard 1,500-mg dose of oral azithromycin can be adm inistered over either 5 or 3 days.