Levofloxacin Dosing
For patients with normal renal function (CrCl ≥50 mL/min), administer levofloxacin 250 mg, 500 mg, or 750 mg orally or intravenously once every 24 hours depending on infection severity, while patients with impaired renal function (CrCl <50 mL/min) require dose adjustment to prevent drug accumulation. 1
Standard Dosing by Renal Function
Normal Renal Function (CrCl ≥50 mL/min)
- 250-750 mg once daily is the standard dosing range, with specific dose determined by infection type and severity 1
- For community-acquired pneumonia, 500 mg once daily for 7-14 days or the high-dose short-course regimen of 750 mg once daily for 5 days are both effective options 2, 3
- The 750 mg daily regimen maximizes concentration-dependent bactericidal activity and may reduce resistance emergence 3, 4
- Oral and intravenous formulations are bioequivalent, allowing seamless transition between routes without dose adjustment 3, 4
Impaired Renal Function (CrCl <50 mL/min)
For CrCl 20-49 mL/min:
For CrCl 10-19 mL/min:
For CrCl <10 mL/min or hemodialysis:
- Administer 750-1000 mg three times weekly (not daily) 6
- Dose should be given after hemodialysis on dialysis days to avoid premature drug clearance 6
- Monitoring of serum drug concentrations should be considered to ensure adequate absorption without excessive accumulation 6
Critical Dosing Principles
Maintain Peak Concentrations
- Increasing the dosing interval is preferred over reducing the dose because fluoroquinolone efficacy is concentration-dependent 6, 2
- Decreasing the dose lowers peak serum concentrations and can compromise treatment efficacy 6
- For severe infections like sepsis with preserved renal function, 750 mg every 24 hours optimizes peak drug plasma concentrations and maximizes probability of favorable response 2
Loading Dose Strategy
- Always initiate therapy with a full loading dose to rapidly achieve therapeutic drug levels, especially in critically ill patients with expanded extracellular volume from fluid resuscitation 2
- This applies even when subsequent maintenance doses will be reduced due to renal impairment 5, 6
Administration Considerations
Timing and Food
- Levofloxacin can be administered without regard to food 1
- Administer at least 2 hours before or 2 hours after antacids containing magnesium or aluminum, sucralfate, metal cations (iron), multivitamins with zinc, or didanosine 1
Hydration
- Maintain adequate hydration to prevent formation of highly concentrated urine and reduce risk of crystalluria 1
Common Pitfalls to Avoid
- Using 500 mg when 750 mg is indicated leads to suboptimal peak concentrations and potential treatment failure, particularly given concentration-dependent killing 2
- Failure to adjust for renal impairment leads to drug accumulation and increased toxicity risk 2, 1
- Assuming less frequent dosing is always better in renal impairment ignores the importance of maintaining adequate antimicrobial coverage 6
- Switching to twice-daily dosing in renal impairment is incorrect; instead, modify the frequency while maintaining once-daily administration 2
Special Populations
Pediatric Patients (≥6 months)
- For children older than 5 years: 10 mg/kg once daily (maximum 750 mg) 2
- For children under 5 years: 7.5-10 mg/kg divided twice daily due to faster drug clearance in this age group 2
- Generally not recommended due to concerns about effects on bone and cartilage growth, but dosing guidelines exist for specific indications like tuberculosis where benefits outweigh risks 2