Levofloxacin Dosing
The standard adult dose of levofloxacin is 500-750 mg once daily, with specific dosing determined by the indication and severity of infection. 1
Adult Dosing by Indication
Standard Dosing (Normal Renal Function)
The FDA-approved dosing for levofloxacin varies by indication 1:
- Community-acquired pneumonia: 750 mg once daily for 5 days (high-dose short course) OR 500 mg once daily for 7-14 days
- Acute pyelonephritis/complicated UTI: 750 mg once daily for 5 days OR 250 mg once daily for 10 days 2
- Uncomplicated UTI: 250 mg once daily for 3 days
- Drug-resistant tuberculosis: 500-1,000 mg daily 3
High-Dose Regimens
For severe infections or drug-resistant organisms, higher doses may be warranted:
- MDR-TB treatment: Up to 1,500 mg daily (approximately 25 mg/kg) has been identified as optimal for achieving therapeutic targets 4
- Severe pneumonia: 750 mg once daily maximizes concentration-dependent killing and reduces resistance development 5
Pediatric Dosing
For children 6 months to 17 years, levofloxacin dosing is weight-based and age-stratified 6:
- Ages 6 months to 5 years: 16-20 mg/kg/day divided every 12 hours (maximum 750 mg/day)
- Ages 5-16 years: 8-10 mg/kg once daily (maximum 750 mg/day)
Important caveat: Long-term fluoroquinolone use in children is not FDA-approved due to concerns about cartilage/bone effects, but experts agree it should be considered for MDR-TB in children when no alternatives exist 3.
For MDR-TB prevention in children, recent modeling suggests 7:
- Dispersible 100 mg tablets: 8-33 mg/kg using weight bands
- Solid 250 mg tablets: 10-42 mg/kg using weight bands
Renal Dose Adjustment
Levofloxacin requires dose adjustment when creatinine clearance falls below 50 mL/min because 80% is renally cleared 3, 1:
- CrCl 20-49 mL/min: 750 mg initial dose, then 750 mg every 48 hours OR 500 mg initial dose, then 250 mg every 24 hours
- CrCl 10-19 mL/min: 750 mg initial dose, then 500 mg every 48 hours OR 500 mg initial dose, then 250 mg every 48 hours
- Hemodialysis: 750-1,000 mg three times weekly; no supplemental dose needed post-dialysis 3
Critical Administration Considerations
Drug Interactions
Levofloxacin must be separated from divalent/trivalent cations by at least 2 hours 3, 1:
- Antacids containing magnesium or aluminum
- Iron supplements
- Multivitamins with zinc
- Sucralfate
- Didanosine buffered formulations
These agents markedly decrease fluoroquinolone absorption through chelation.
Hepatic Impairment
No dose adjustment needed—levofloxacin undergoes minimal hepatic metabolism (<5%) 3, 1.
Pregnancy
Avoid in pregnancy due to teratogenic effects demonstrated in animal studies 3.
Practical Dosing Algorithm
Determine indication and severity
- Mild-moderate infection: 500 mg daily
- Severe infection or resistant organism: 750 mg daily
- MDR-TB: 750-1,000 mg daily (consider up to 1,500 mg for optimal outcomes)
Assess renal function
- CrCl ≥50 mL/min: Standard dosing
- CrCl <50 mL/min: Reduce frequency or dose per table above
Check for interacting medications
- Separate from cation-containing products by 2+ hours
Duration
- Short-course high-dose (750 mg × 5 days) for CAP, pyelonephritis
- Standard course (500 mg × 7-14 days) for most infections
- Extended therapy (months) for MDR-TB
The high-dose, short-course regimen (750 mg × 5 days) offers advantages of improved compliance, maximized concentration-dependent killing, and reduced resistance selection while maintaining equivalent efficacy to longer standard-dose regimens 5.