Levofloxacin (Favoxil) Dosing and Administration
Levofloxacin should be dosed at 500-750 mg once daily for most infections, with the specific dose and duration determined by the infection type and severity. 1, 2
Standard Adult Dosing by Indication
Respiratory Tract Infections
- Community-Acquired Pneumonia (CAP): 750 mg once daily for 5 days for mild-to-moderate CAP, or 500 mg once daily for 7-14 days for severe CAP or infections involving multi-drug resistant Streptococcus pneumoniae (MDRSP) 1, 2
- Nosocomial Pneumonia: 750 mg once daily for 7-14 days, with mandatory combination therapy using an anti-pseudomonal β-lactam when Pseudomonas aeruginosa is documented or suspected 1, 2
- Acute Bacterial Sinusitis: 750 mg once daily for 5 days, or 500 mg once daily for 10-14 days 1, 2
- Acute Bacterial Exacerbation of Chronic Bronchitis: 500 mg once daily for 7 days 1, 2
Skin and Soft Tissue Infections
- Complicated Skin Infections: 750 mg once daily for 7-14 days 1, 2
- Uncomplicated Skin Infections: 500 mg once daily for 7-10 days 2
Urinary Tract Infections
- Complicated UTI/Acute Pyelonephritis: 750 mg once daily for 5 days, or 500 mg once daily for 10 days 1, 2
- Uncomplicated UTI: 250 mg once daily for 3 days 2
- Chronic Bacterial Prostatitis: 500 mg once daily for 28 days 2
Drug-Resistant Tuberculosis
- MDR-TB: 750-1,000 mg once daily, with 1,000 mg/day representing the optimal balance between efficacy and tolerability; use only when first-line agents cannot be used 1, 3
Pediatric Dosing
Levofloxacin is generally not recommended for routine pediatric use due to concerns about effects on bone and cartilage growth, but may be considered for MDR-TB or resistant infections when benefits outweigh risks. 1, 3
- Children ≥5 years: 10 mg/kg once daily (maximum 750 mg) 1
- Children 6 months to <5 years: 10 mg/kg divided every 12 hours (maximum 750 mg/day) due to faster drug clearance 1
Renal Dose Adjustments
Levofloxacin is 80% renally cleared and requires dose adjustment for creatinine clearance <50 mL/min. 1, 4
- CrCl ≥50 mL/min: No adjustment needed 1
- CrCl <50 mL/min: Reduce to 750-1,000 mg three times weekly 1
- Hemodialysis: No supplemental doses needed after dialysis, as levofloxacin is not cleared by hemodialysis 1, 4
Hepatic Considerations
- No dose adjustment required for hepatic disease, as drug levels are unaffected by liver dysfunction 1, 4
Critical Administration Requirements
Do not administer levofloxacin within 2 hours of antacids or medications containing divalent cations (calcium, magnesium, aluminum, iron, zinc), as these agents markedly decrease fluoroquinolone absorption. 1, 4
Route of Administration
- Oral and intravenous formulations are bioequivalent, allowing seamless transition between routes without dose adjustment 4, 5
- Oral bioavailability approaches 100% and is minimally affected by food 5
Contraindications and Special Warnings
- Avoid in pregnancy due to teratogenic effects (class effect of fluoroquinolones) 1, 3
- Reserve for drug-resistant organisms or first-line drug intolerance; not a first-line agent for most bacterial infections 3
- Monitor for tendinitis and tendon rupture, particularly with long-term use and in patients on concurrent corticosteroids 3
- Obtain baseline ECG in elderly patients to identify pre-existing QT prolongation 1
Common Adverse Effects
- Gastrointestinal: Nausea and bloating in 0.5-1.8% of patients 1, 3
- Neurologic: Dizziness and insomnia in 0.5% of patients 1, 3
- Cutaneous: Rash and pruritus in 0.2-0.4% of patients 1, 3
Key Clinical Pitfalls to Avoid
- Do not use as monotherapy for Pseudomonas aeruginosa infections; always combine with an anti-pseudomonal β-lactam 1, 2
- Previous fluoroquinolone exposure may preclude use due to potential resistance development 1
- Monitor blood glucose in diabetic patients, as fluoroquinolones carry risk of hypoglycemia 1
- Obtain baseline renal function in elderly patients before initiating therapy 1