Levofloxacin Dosage for Adults with Normal Renal and Hepatic Function
For a typical adult patient with no significant medical history and normal renal and hepatic function, levofloxacin is dosed at 250 mg, 500 mg, or 750 mg orally once every 24 hours, depending on the specific infection being treated. 1
Standard Dosing by Indication
The FDA-approved dosing regimens for adults with creatinine clearance ≥50 mL/min are infection-specific 1:
Respiratory Tract Infections
- Community-acquired pneumonia (CAP): 500 mg once daily for 7-14 days 1 OR 750 mg once daily for 5 days for a high-dose short-course regimen 1, 2
- Nosocomial pneumonia: 750 mg once daily for 7-14 days 1
- Acute bacterial sinusitis: 750 mg once daily for 5 days OR 500 mg once daily for 10-14 days 1
- Acute bacterial exacerbation of chronic bronchitis: 500 mg once daily for 7 days 1
Urinary Tract Infections
- Uncomplicated UTI: 250 mg once daily for 3 days 1
- Complicated UTI or acute pyelonephritis: 750 mg once daily for 5 days OR 250 mg once daily for 10 days 1
Skin and Soft Tissue Infections
- Complicated skin and skin structure infections: 750 mg once daily for 7-14 days 1
- Uncomplicated skin infections: 500 mg once daily for 7-10 days 1
Other Indications
- Chronic bacterial prostatitis: 500 mg once daily for 28 days 1
- Inhalational anthrax (post-exposure): 500 mg once daily for 60 days 1
- Plague: 500 mg once daily for 10-14 days 1
Key Administration Principles
The 750 mg once-daily high-dose regimen maximizes concentration-dependent bactericidal activity and is particularly important for serious infections, as fluoroquinolone efficacy correlates directly with peak plasma concentrations 2, 3. This higher dose achieves superior clinical success rates for severe infections while maintaining the convenience of once-daily dosing 2.
Sequential therapy (intravenous to oral) may be instituted at any point during treatment, as oral levofloxacin has approximately 100% bioavailability and produces plasma concentrations bioequivalent to intravenous administration 1, 4.
Critical Precautions
Do not administer levofloxacin within 2 hours of antacids or medications containing divalent cations (calcium, magnesium, aluminum, iron), as these agents markedly decrease fluoroquinolone absorption 5, 4.
Always verify renal function before initiating therapy, as levofloxacin is 80% renally eliminated and requires dose adjustment when creatinine clearance falls below 50 mL/min 2, 5. For patients with normal renal function (CrCl ≥50 mL/min), no adjustment is needed 1.
Common Pitfall to Avoid
Using 500 mg when 750 mg is indicated can lead to suboptimal peak concentrations and treatment failure, particularly for serious infections like nosocomial pneumonia or complicated skin infections where concentration-dependent killing is critical 2. The FDA label clearly specifies 750 mg for these indications 1.