UTI Acute uncomplicated: 250 mg every 12 hr for 3 days. Mild/moderate: 250 mg every 12 hr for 7-14 days. Severe: 500 mg every 12 hr for 7-14 days. 
Chronic bacterial prostatitis Mild/moderate: 500 mg every 12 hr for 28 days. 
Lower resp tract infection Mild/moderate: 500 mg every 12 hr for 7-14 days. Severe/complicated: 750 mg every 12 hr for 7-14 days. 
Acute sinusitis Mild/moderate: 500 mg every 12 hr for 10 days. 
Skin & skin stricture infection Mild/moderate: 500 mg every 12 hr for 7-14 days. Severe/complicated: 750 mg every 12 hr for 7-14 days. 
Bone & joint infection Mild/moderate: 500 mg every 12 hr for 4-6 days. Severe/complicated: 750 mg every 12 hr for 4-6 days. 
Intraabdominal infection Complicated: 500 mg every 12 hr for 7-14 days in conjunction w/ metronidazole. 
Infectious diarrhea Mild/moderate/severe: 500 mg every 12 hr for 5-7 days. 
Typhoid fever Mild/moderate: 500 mg every 12 hr for 10 days. 
Urethral & cervical gonococcal infection Uncomplicated: 250 mg as single dose. 
Inhalational anthrax (post-exposure) Adult 500 mg every 12 hr for 60 days. 
Childn <18 yr 15 mg/kg/dose every 12 hr for 60 days. Max: Not to exceed 500 mg/dose. 
Renal impairment CrCl 30-50 mL/min 250-500 mg every 12 hr, 
5-29 mL/min 250-500 mg every 18 hr, 
hemodialysis or peritoneal dialysis 250-500 mg every 24 hr (after dialysis).