Recommended Metronidazole Dosing for Pediatric Patients
The recommended dose of metronidazole for pediatric patients varies by indication, but generally ranges from 30-40 mg/kg/day divided every 8 hours for most infections, with a maximum of 500 mg per dose. 1
General Dosing Guidelines
- For most pediatric infections requiring metronidazole, the standard dosing is 30-40 mg/kg/day divided into three doses (every 8 hours), with a maximum dose per administration of 500 mg 1
- For children with amebiasis, the FDA-approved dosing is 35-50 mg/kg/24 hours, divided into three doses orally for 10 days 2
- For anaerobic bacterial infections, the FDA-approved dosing is 7.5 mg/kg every six hours (approximately 500 mg for a 70 kg adult), with a maximum of 4 g per 24-hour period 2
- The standard duration of therapy for most infections is 7-10 days, though some infections may require longer treatment 1, 2
Condition-Specific Dosing
Clostridium difficile Infection (CDI)
- For initial episode or first recurrence of non-severe CDI: 7.5 mg/kg/dose three or four times daily for 10 days (maximum 500 mg per dose) 3, 4
- For severe or fulminant CDI requiring IV therapy: 10 mg/kg/dose three times daily (maximum 500 mg per dose) 3, 4
- For second or subsequent recurrences, oral vancomycin is recommended over metronidazole 3, 4
Intra-abdominal Infections
- For intra-abdominal infections: 30-40 mg/kg/day divided every 8 hours as part of combination therapy 1
- Metronidazole should be combined with other appropriate antibiotics for complicated intra-abdominal infections 1
Other Infections
- For children below 12 years of age with anaerobic infections, dental infections, or protozoan infections: 20-30 mg/kg/day divided doses 5
- For children 12 years and older: 200 mg to a maximum of 2000 mg per day 5
Special Considerations
- For severe hepatic disease, doses should be reduced due to slower metabolism and potential accumulation of metronidazole and its metabolites 2
- Once-daily dosing (30 mg/kg/dose) has been studied in pediatric appendicitis patients and achieved adequate target concentrations for Bacteroides fragilis with MIC ≤2 mcg/mL 6
- In severely malnourished children, dosage reduction to 12 mg/kg/day (60% reduction from standard dose) may be warranted due to altered drug metabolism 7
- Metronidazole dosing should be adjusted based on the severity of infection 1
Administration Routes
- Metronidazole can be administered orally or intravenously, with parenteral administration likely resulting in higher bioavailability 3, 1
- For severe infections, initial intravenous therapy is often recommended before transitioning to oral therapy 2, 8
Monitoring and Safety
- No test doses are necessary when starting low-dose metronidazole for inflammatory skin disease 3
- Monitoring of serum levels may be necessary in elderly patients due to altered pharmacokinetics 2
- The most common side effects are gastrointestinal (nausea, vomiting, bitter taste) and are typically mild 9