What is the appropriate dosing for Levaquin (levofloxacin) in treating infections?

Levofloxacin (Levaquin) Dosing

Standard Adult Dosing

For most bacterial infections in adults with normal renal function, administer levofloxacin 500-750 mg orally or intravenously once daily. 1

Dosing by Indication

• Community-acquired pneumonia (CAP): 750 mg once daily for 5 days (high-dose short-course) or 500 mg once daily for 7-14 days 2, 3
• Nosocomial pneumonia: 750 mg once daily for 7-14 days, administered as sequential IV to oral therapy 4, 5
• Acute bacterial sinusitis: 750 mg once daily for 5 days or 500 mg once daily for 10-14 days 2, 5
• Complicated urinary tract infections/acute pyelonephritis: 750 mg once daily for 5 days or 500 mg once daily for 7-10 days 6, 3
• Complicated skin and skin structure infections: 750 mg once daily for 7-14 days 2, 5
• Drug-resistant tuberculosis: 500-1,000 mg once daily (optimal dose is 750-1,000 mg daily for MDR-TB) 4, 7

The 750 mg high-dose regimen maximizes concentration-dependent bactericidal activity and may reduce resistance development while improving compliance through shorter treatment duration. 3, 8

Renal Dose Adjustments

Dosage adjustment is mandatory when creatinine clearance falls below 50 mL/min because levofloxacin is 80% renally cleared. 4

Adjustment Algorithm

• CrCl ≥50 mL/min: No adjustment needed; use standard dosing 1
• CrCl 20-49 mL/min:
  • For 750 mg regimen: Give 750 mg initial dose, then 750 mg every 48 hours 1
  • For 500 mg regimen: Give 500 mg initial dose, then 250 mg every 24 hours 1
• CrCl 10-19 mL/min: Give 500 mg initial dose, then 250 mg every 48 hours 1
• Hemodialysis patients: Give 750-1,000 mg three times weekly (not daily), administered after dialysis sessions 4

Critical point: Levofloxacin is NOT cleared by hemodialysis, so no supplemental doses are needed post-dialysis. 4 However, the drug should be given after dialysis to facilitate directly observed therapy and avoid premature removal. 4

Pediatric Dosing

Levofloxacin is generally NOT recommended for routine pediatric use due to concerns about effects on bone and cartilage growth. 4, 7 However, it should be considered when benefits outweigh risks, particularly for multidrug-resistant tuberculosis. 4, 7

When Pediatric Use is Necessary

• Children ≥5 years: 10 mg/kg once daily (maximum 750 mg) 7, 2
• Children 6 months to <5 years: 10 mg/kg divided every 12 hours (maximum 750 mg/day) due to faster drug clearance in this age group 7, 6

The optimal pediatric dose for tuberculosis is not definitively established, but most experts agree the drug should be considered for children with MDR-TB. 4

Critical Administration Requirements

Never administer levofloxacin within 2 hours of antacids or medications containing divalent cations (magnesium, aluminum, calcium, iron, zinc). 4, 7

• These agents markedly decrease fluoroquinolone absorption through chelation, even potentially affecting IV administration 7, 6
• Separate administration by at least 2 hours before or after levofloxacin 1
• This includes multivitamins with zinc and didanosine chewable/buffered tablets 1

Maintain adequate hydration to prevent formation of highly concentrated urine and avoid crystalluria. 1

Special Population Considerations

Pregnancy

Avoid levofloxacin in pregnancy due to teratogenic effects—this is a class effect of all fluoroquinolones. 4, 7

Hepatic Disease

No dose adjustment required for hepatic impairment as drug levels are not affected by liver disease. 4 However, use with caution and increased monitoring in severe hepatic disease. 4

Route Transition

Oral and IV formulations are bioequivalent, allowing seamless transition between routes without dose adjustment. 9, 3 Oral absorption is rapid and complete, with bioavailability approaching 100%. 9

Common Pitfalls to Avoid

• Using 500 mg when 750 mg is indicated for severe infections: This leads to suboptimal peak concentrations, treatment failure, and potential resistance development due to the concentration-dependent killing mechanism of fluoroquinolones 6
• Failing to adjust for renal impairment: Results in drug accumulation and increased toxicity risk, particularly neurologic adverse effects 4, 6
• Not separating from divalent cations: Causes significant malabsorption and treatment failure 7, 6
• Using as first-line for drug-susceptible tuberculosis: Fluoroquinolones should only be used when first-line agents cannot be tolerated or for drug-resistant disease 4

Monitoring and Adverse Effects

Common adverse effects occur at low rates: 4, 7

• Gastrointestinal (nausea, bloating): 0.5-1.8%
• Neurologic (dizziness, insomnia, tremulousness, headache): 0.5%
• Cutaneous (rash, pruritus, photosensitivity): 0.2-0.4%

For tuberculosis treatment exceeding 3 months, monitor hepatic enzymes and thyroid function at baseline and every 3 months during prolonged therapy. 4