Ofloxacin for Bacterial Diarrhea
For acute bacterial diarrhea, ofloxacin should be dosed at 400 mg orally as a single dose or 200-400 mg twice daily for 3 days, with single-dose therapy combined with loperamide being the most effective regimen for rapid symptom resolution. 1
Recommended Dosing Regimens
Standard Treatment Options
- Single dose: 400 mg orally once 1
- 3-day course: 400 mg orally every 12 hours for 3 days 1
- Alternative 3-day course: 200 mg orally every 12 hours for 3 days 2, 3
The FDA-approved dosing for various infections ranges from 200-400 mg every 12 hours, with duration depending on infection severity 4.
Combination Therapy (Most Effective)
For moderate to severe traveler's diarrhea, combine ofloxacin 400 mg single dose with loperamide (4 mg initial dose, then 2 mg after each loose stool, maximum 16 mg/24 hours) for superior efficacy. 1, 5
- This combination reduces illness duration more effectively than ofloxacin alone (63% of patients passed no further unformed stools after initial doses, 91% well within 24 hours) 5
- Particularly effective for enterotoxigenic E. coli (ETEC) and culture-negative diarrhea 5
Clinical Efficacy Data
Treatment Duration
Three days of ofloxacin is as effective as five days, with clinical cure rates of 95% versus 89% respectively 3. Single-dose therapy combined with loperamide outperforms multi-day ofloxacin monotherapy 5.
Pathogen Coverage
Ofloxacin demonstrates excellent activity against:
- Vibrio cholerae, V. parahaemolyticus (MIC90: 0.047-0.38 mg/L) 2
- Shigella species (flexneri, boydii, sonnei) 2, 3
- ETEC and other E. coli strains 5, 3
- Aeromonas and Plesiomonas species 2
- Salmonella species 6
Clinical cure rates of 96.5% for diarrhea and 100% for dysentery have been documented 2.
Important Clinical Considerations
When to Use Ofloxacin
- Severe travelers' diarrhea: Fluoroquinolones may be used for severe, non-dysenteric diarrhea (weak recommendation) 1
- Azithromycin is preferred for severe diarrhea, especially dysenteric illness or febrile diarrhea (strong recommendation) 1
- Geographic resistance patterns matter: Avoid fluoroquinolones as first-line in Southeast Asia and India due to Campylobacter resistance 1
Critical Contraindications
Do not use ofloxacin if clinical suspicion exists for Campylobacter, Salmonella, Shigella, or other invasive diarrhea in high-resistance areas. 1
Loperamide Safety Warning
Discontinue loperamide if symptoms worsen or dysentery develops, even when combined with antibiotics 1. Loperamide is contraindicated in children under 2 years 1.
Special Populations
Renal Impairment
- Creatinine clearance 20-50 mL/min: Give usual dose every 24 hours instead of every 12 hours 4
- Creatinine clearance <20 mL/min: Give half the usual dose every 24 hours 4
Hepatic Impairment
Maximum dose should not exceed 400 mg daily in patients with severe liver dysfunction (cirrhosis with or without ascites) 4.
Pregnancy
Fluoroquinolones should be avoided in pregnancy due to teratogenic effects 1.
Drug Interactions
Administer ofloxacin at least 2 hours before or after antacids containing calcium, magnesium, or aluminum; sucralfate; iron; multivitamins with zinc; or didanosine, as these significantly reduce absorption. 4