Levofloxacin Dosing for Typhoid Fever
For uncomplicated typhoid fever in adults, administer levofloxacin 500-750 mg orally once daily for 7 days, with the 750 mg dose preferred for optimal efficacy and rapid defervescence.
Standard Adult Dosing Regimen
The recommended dose is levofloxacin 750 mg orally once daily for 7 days. 1, 2 This higher dose achieves superior bactericidal concentrations and has demonstrated excellent clinical outcomes in multiple studies of typhoid fever patients. 1
- Clinical trials show that 750 mg daily produces defervescence within an average of 2.4 days (range 1-5 days), with 100% clinical cure rates and no relapses or carrier states. 1, 3
- The alternative 500 mg daily dose is also effective, achieving 100% clinical efficacy with minimal adverse effects, though defervescence may be slightly slower. 3, 2
Route of Administration Options
Oral therapy is preferred for uncomplicated typhoid fever. 1, 3, 2
- For patients unable to tolerate oral medications, intravenous levofloxacin 500 mg once daily for 7 days is equally effective, with 96% cure rates. 2
- Both routes achieve complete microbiological clearance and prevent carrier states when given for the full 7-day course. 3, 2
Pediatric Considerations
Levofloxacin is generally not recommended for routine pediatric use due to concerns about effects on bone and cartilage growth. 4, 5 However, when benefits outweigh risks in multidrug-resistant typhoid:
- Children ≥5 years: 10 mg/kg once daily (maximum 750 mg). 5
- Children <5 years: 10 mg/kg divided every 12 hours due to faster drug clearance. 5
Critical Clinical Context
Exercise caution when treating travelers returning from India, as fluoroquinolone-resistant Salmonella typhi strains with decreased susceptibility are increasingly common. 4 In areas with documented fluoroquinolone resistance, alternative agents should be strongly considered.
Treatment Duration and Monitoring
- Complete the full 7-day course to ensure microbiological eradication and prevent relapse or carrier states. 1, 3, 2
- Expect defervescence within 2-5 days; persistent fever beyond 5 days suggests treatment failure or resistant organisms. 1, 3
- Follow-up blood cultures at 30 days confirm eradication and rule out carrier states. 3
Important Contraindications
Avoid levofloxacin in pregnancy due to teratogenic effects. 5, 6 Alternative agents must be selected for pregnant patients with typhoid fever.
Renal Dose Adjustments
For creatinine clearance <50 mL/min, reduce to 750 mg three times weekly or adjust based on specific clearance values. 5 Levofloxacin is 80% renally cleared and requires dose modification to prevent accumulation and toxicity. 5
Common Pitfalls to Avoid
- Do not administer within 2 hours of antacids or medications containing divalent cations (calcium, magnesium, aluminum, iron), as these markedly decrease fluoroquinolone absorption. 5
- Do not use 500 mg when 750 mg is indicated, as suboptimal peak concentrations may lead to treatment failure, particularly with concentration-dependent killing. 6
- Do not discontinue therapy early even if fever resolves quickly, as incomplete courses increase relapse risk and carrier state development. 3