Metronidazole Dosing for a 5-Year-Old Child Weighing 20kg
For a 5-year-old child weighing 20kg, the recommended dose of metronidazole is 7.5 mg/kg/dose three times daily, which equals 150 mg (7.5 mL of a 20 mg/mL suspension) per dose. 1
Dosing Calculation
- The standard pediatric dosing for metronidazole for most infections is 7.5 mg/kg/dose three or four times daily 1
- For a 20kg child: 7.5 mg/kg × 20kg = 150 mg per dose
- Assuming standard metronidazole suspension concentration of 20 mg/mL:
- 150 mg ÷ 20 mg/mL = 7.5 mL per dose 1
Dosing by Indication
- For Clostridium difficile infection: 7.5 mg/kg/dose three or four times daily for 10 days (150 mg or 7.5 mL per dose) 1
- For anaerobic infections: 7.5 mg/kg/dose three or four times daily for 7-10 days (150 mg or 7.5 mL per dose) 1
- For more severe infections, some guidelines suggest higher dosing of 10 mg/kg/dose three times daily (200 mg or 10 mL per dose) 2
Alternative Dosing Regimens
- Some institutions use a higher total daily dose of 30-40 mg/kg/day divided every 8 hours (10-13.3 mg/kg/dose) 2
- This would equal 200-266 mg per dose (10-13.3 mL) for a 20kg child
- Recent pharmacokinetic studies suggest once-daily dosing at 30 mg/kg may be effective for certain indications like appendicitis (600 mg or 30 mL once daily) 3
Important Considerations
- Ensure completion of the full course of therapy even if symptoms improve before completion 1
- Monitor for common side effects including nausea, metallic taste, and gastrointestinal discomfort 1
- Avoid prolonged or repeated courses of metronidazole due to risk of cumulative neurotoxicity 1
- For C. difficile infection, if no response within 5-7 days, consider switching to oral vancomycin 1