Fluoroquinolone Dosing Guidelines
For most infections, fluoroquinolones should be dosed according to infection type, severity, and renal function, with levofloxacin 750 mg daily for 5-7 days being the optimal regimen for most serious infections in patients with normal renal function. 1, 2
Standard Dosing for Adults with Normal Renal Function
Levofloxacin
- Community-acquired pneumonia: 750 mg once daily for 5 days 2, 3
- Complicated UTI/Pyelonephritis: 750 mg once daily for 5 days 1, 4
- Acute bacterial sinusitis: 750 mg once daily for 5 days 2
- Sepsis: 750 mg once daily IV/PO 5, 6
- Plague (pneumonic/septicemic): 750 mg every 24 hours IV or PO 5
Ciprofloxacin
- UTI: 500 mg twice daily PO or 400 mg every 8-12 hours IV 5, 4
- Pneumonic/septicemic plague: 400 mg every 8 hours IV or 750 mg every 12 hours PO 5
- Sepsis: 400 mg every 8 hours IV 5
Renal Dosage Adjustments
Levofloxacin Dosing in Renal Impairment 1
- CrCl ≥50 mL/min: No adjustment needed
- CrCl 20-49 mL/min: Initial 750 mg dose, then 750 mg every 48 hours
- CrCl 10-19 mL/min: Initial 750 mg dose, then 500 mg every 48 hours
- Hemodialysis: No supplemental doses required after hemodialysis
- CAPD: No supplemental doses required
Ciprofloxacin Dosing in Renal Impairment
- CrCl 30-50 mL/min: 250-500 mg every 12 hours
- CrCl 5-29 mL/min: 250-500 mg every 18 hours
- Hemodialysis/Peritoneal dialysis: 250-500 mg every 24 hours (after dialysis)
Special Populations
Pediatric Patients
Levofloxacin (children ≥6 months) 5:
- Body weight <50 kg: 8 mg/kg every 12 hours IV or PO (maximum 250 mg/dose)
- Body weight ≥50 kg: 500-750 mg every 24 hours IV or PO
Ciprofloxacin (children ≥1 month) 5:
- 10 mg/kg every 8 or 12 hours IV
- 15 mg/kg every 8 or 12 hours PO
- Maximum: 400 mg/dose IV, 750 mg/dose PO
Elderly Patients 1
- No dosage adjustment based on age alone
- Adjust based on renal function as elderly patients are more likely to have decreased renal function
- Monitor closely for adverse effects, particularly tendon disorders, QT prolongation, and hepatotoxicity
Infection-Specific Considerations
Respiratory Infections
- Community-acquired pneumonia: Levofloxacin 750 mg daily for 5 days is as effective as 500 mg daily for 10 days 2, 3
- Tuberculosis: Levofloxacin 500-1,000 mg daily for adults (not first-line therapy) 5
Urinary Tract Infections
- Uncomplicated UTI: Levofloxacin 250 mg daily for 3 days 4
- Complicated UTI/Pyelonephritis: Levofloxacin 750 mg daily for 5 days 2, 4
Sepsis
- Initial therapy: High-dose fluoroquinolones with loading dose 5
- Optimal dosing strategy: Maximize peak drug plasma concentrations 5
Administration Guidelines
Drug Interactions
- Administer at least 2 hours before or after:
- Antacids containing magnesium or aluminum
- Sucralfate
- Metal cations (iron, zinc)
- Multivitamins with zinc
- Didanosine products 1
Hydration
- Maintain adequate hydration to prevent crystalluria 1
Food
- Can be administered without regard to food 1
Monitoring
- Renal function: Before and during therapy in patients with renal insufficiency 1
- Clinical response: Improvement expected within 48-72 hours; reassess if no improvement 6
- Drug levels: Consider monitoring in critically ill patients to ensure adequate dosing 5
Important Considerations and Cautions
- High-dose, short-course regimens maximize concentration-dependent bactericidal activity and may reduce resistance development 2, 3
- Fluoroquinolones are contraindicated in pregnancy due to teratogenic effects 5
- Use with caution in patients with risk factors for QT prolongation 1
- Elderly patients are at increased risk for tendon disorders, particularly with concomitant corticosteroid therapy 1
- Monitor for hepatotoxicity, especially in patients ≥65 years 1
The high-dose, short-course levofloxacin regimen (750 mg daily for 5 days) offers advantages of better compliance, reduced potential for resistance, and equivalent efficacy compared to traditional longer courses 2, 7.