What is the typical dosage of ofloxacin (a fluoroquinolone antibiotic) for a patient with normal renal function?

Ofloxacin Dosage in Adults with Normal Renal Function

For adults with normal renal function (creatinine clearance >50 mL/min), ofloxacin is dosed at 200-400 mg orally every 12 hours, with the specific dose and duration determined by the infection type and severity. 1

Standard Dosing by Indication

The FDA-approved dosing regimen varies based on the specific infection being treated 1:

Respiratory Tract Infections

• Acute bacterial exacerbation of chronic bronchitis: 400 mg every 12 hours for 10 days 1
• Community-acquired pneumonia: 400 mg every 12 hours for 10 days 1

Skin and Soft Tissue Infections

• Uncomplicated skin and skin structure infections: 400 mg every 12 hours for 10 days 1

Genitourinary Infections

• Uncomplicated gonorrhea: 400 mg as a single dose 1
• Nongonococcal cervicitis/urethritis (C. trachomatis): 300 mg every 12 hours for 7 days 1
• Mixed cervical/urethral infection (C. trachomatis and N. gonorrhoeae): 300 mg every 12 hours for 7 days 1
• Acute pelvic inflammatory disease: 400 mg every 12 hours for 10-14 days 1
• Uncomplicated cystitis (E. coli or K. pneumoniae): 200 mg every 12 hours for 3 days 1
• Uncomplicated cystitis (other pathogens): 200 mg every 12 hours for 7 days 1
• Complicated urinary tract infections: 200 mg every 12 hours for 10 days 1
• Prostatitis (E. coli): 300 mg every 12 hours for 6 weeks 1

Pharmacokinetic Considerations

Ofloxacin demonstrates near-complete oral bioavailability (95-100%), with peak serum concentrations of 2-3 mg/L achieved after a 400 mg oral dose and an elimination half-life of 5-8 hours in patients with normal renal function. 2

• The drug is predominantly eliminated renally, making it particularly suitable for urinary tract infections where concentrations approximating 100 mcg/mL are maintained for up to 12 hours after dosing 3
• Unlike other fluoroquinolones (ciprofloxacin, enoxacin), ofloxacin has minimal drug interactions and does not significantly affect theophylline metabolism 2

Critical Drug Administration Timing

Ofloxacin must not be administered within 2 hours before or after antacids containing calcium, magnesium, or aluminum; sucralfate; iron supplements; multivitamins with zinc; or didanosine formulations, as these significantly reduce fluoroquinolone absorption. 1

Common Pitfalls to Avoid

• Do not use the 200 mg dose for respiratory or complicated infections: The lower dose is reserved for uncomplicated cystitis only; respiratory and complicated infections require 400 mg every 12 hours 1
• Do not assume once-daily dosing is appropriate in normal renal function: The every-12-hour interval is necessary to maintain therapeutic concentrations given the 5-8 hour half-life 2
• Do not overlook the single-dose regimen for uncomplicated gonorrhea: This is the only indication where a single 400 mg dose is appropriate 1

Special Population Considerations

For patients with hepatic cirrhosis (with or without ascites), the maximum daily dose should not exceed 400 mg total due to reduced excretion 1. This represents a significant dose reduction from the standard 800 mg daily dose used for most infections.