Co-amoxiclav Dosing Calculation
Give 3.2 mL of Co-amoxiclav drops (62.5mg/mL) every 8 hours for 7 days.
Calculation Breakdown
Total daily dose needed:
- Weight: 10 kg
- Prescribed dose: 40 mg/kg/day
- Total daily dose: 10 kg × 40 mg/kg = 400 mg/day 1
Dose per administration:
- The prescription states "BID" (twice daily), but the formulation specifies "every 8 hours" (three times daily)
- Important caveat: There is a discrepancy in your prescription. BID means twice daily (every 12 hours), but you've written "every 8 hours" which is three times daily (TID). Every 8 hours dosing is the standard for this formulation 1.
Using every 8 hours (TID) dosing:
- 400 mg/day ÷ 3 doses = 133.3 mg per dose
- Available concentration: 62.5 mg/mL
- Volume needed: 133.3 mg ÷ 62.5 mg/mL = 2.13 mL per dose
However, if following standard pediatric dosing from FDA labeling:
- For a 10 kg child with moderate infections, the recommended dose is 20 mg/kg/day every 8 hours = 200 mg/day total 1
- This equals: 200 mg/day ÷ 3 = 66.7 mg per dose
- Volume: 66.7 mg ÷ 62.5 mg/mL = 1.07 mL per dose
For more severe infections (40 mg/kg/day every 8 hours):
- 40 mg/kg/day × 10 kg = 400 mg/day 1
- 400 mg/day ÷ 3 doses = 133.3 mg per dose
- Volume: 133.3 mg ÷ 62.5 mg/mL = 2.13 mL per dose
Critical Clarification Needed
The prescription contains conflicting instructions: "BID" (twice daily) versus "every 8 hours" (three times daily). The 62.5 mg/mL suspension formulation is typically dosed every 8 hours, not twice daily 1.
If the intent is 40 mg/kg/day divided every 8 hours (standard for severe infections): Give 2.1 mL every 8 hours 1.
If the intent is truly BID dosing: The FDA recommends using higher concentration formulations (200 mg/28.5 mg per 5 mL or 400 mg/57 mg per 5 mL) for twice-daily dosing, as the q12h regimen is associated with significantly less diarrhea 1, 2, 3. For 40 mg/kg/day BID with current formulation: give 3.2 mL every 12 hours.
Recommendation
Clarify the intended dosing frequency with the prescriber. The most common error is mixing BID notation with "every 8 hours" instructions, which are incompatible 1.