Biaxin - Clinical Pharmacology

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In healthy human subjects, steady-state peak plasma clarithromycin concentrations of approximately 2 to 3 µg/mL were achieved about 5 to 8 hours after oral administration of 2 x 500 mg BIAXIN XL tablets once daily; for 14-OH clarithromycin, steady-state peak plasma concentrations of approximately 0.8 µg/mL were attained about 6 to 9 hours after dosing. Steady-state peak plasma clarithromycin concentrations of approximately 1 to 2 µg/mL were achieved about 5 to 6 hours after oral administration of a single 500 mg BIAXIN XL tablet once daily; for 14-OH clarithromycin, steady-state peak plasma concentrations of approximately 0.6 µg/mL were attained about 6 hours after dosing.

When 250 mg doses of clarithromycin as BIAXIN suspension were administered to fasting healthy adult subjects, peak plasma concentrations were attained around 3 hours after dosing. Steady-state peak plasma concentrations were attained in 2 to 3 days and were approximately 2 µg/mL for clarithromycin and 0.7 µg/mL for 14-OH clarithromycin when 250-mg doses of the clarithromycin suspension were administered every 12 hours. Elimination half-life of clarithromycin (3 to 4 hours) and that of 14-OH clarithromycin (5 to 7 hours) were similar to those observed at steady state following administration of equivalent doses of BIAXIN tablets.

For adult patients, the bioavailability of 10 mL of the 125 mg/5 mL suspension or 10 mL of the 250 mg/5 mL suspension is similar to a 250 mg or 500 mg tablet, respectively. In children requiring antibiotic therapy, administration of 7.5 mg/kg q12h doses of clarithromycin as the suspension generally resulted in steady-state peak plasma concentrations of 3 to 7 µg/mL for clarithromycin and 1 to 2 µg/mL for 14-OH clarithromycin.

In HIV-infected children taking 15 mg/kg every 12 hours, steady-state clarithromycin peak concentrations generally ranged from 6 to 15 µg/mL. Clarithromycin penetrates into the middle ear fluid of children with secretory otitis media.

CONCENTRATION

(after 7.5 mg/kg q12h for 5 doses)