Adult Usual dose: 250-500 mg bid. Acute exacerbation of cystic fibrosis associated w/ Pseudomonas aeruginosa infectionAdolescent & childn ≥5 yr 20 mg/kg up to max: 750 mg bid. Acute uncomplicated cystitisWomen 100 mg bid. Gonorrhea Single dose of 250-500 mg. Meningococcal meningitis prophylaxis Single dose of 500 mg. Surgical infection prophylaxis Single dose of 750 mg given 60-90 min prior to procedure.
Decreased absorption w/ Mg-Al antacids. Elevated serum conc of theophylline. Metabolism may be induced w/ rifampicin. May be antagonistic in combination w/ chloramphenicol.