Dosing Volume Calculation for Amoxicillin
To administer 680mg of amoxicillin from a 400mg per 5mL suspension, you need 8.5mL of the medication.
Calculation Method
The calculation for determining the correct dosing volume follows a simple proportion:
- Concentration: 400mg per 5mL
- Required dose: 680mg
Using the formula:
- Volume (mL) = (Desired dose × Volume of standard dose) ÷ Standard dose
- Volume (mL) = (680mg × 5mL) ÷ 400mg
- Volume (mL) = 3400 ÷ 400
- Volume (mL) = 8.5mL
Verification and Administration Tips
- Always double-check your calculation before administering medication to children
- Use a proper oral syringe or medication measuring device calibrated in milliliters
- Never use household spoons as they are inaccurate for medication dosing 1
- Administer at the start of a meal to minimize gastrointestinal intolerance 1
Important Considerations for Pediatric Dosing
- For children weighing less than 40kg, amoxicillin dosing is weight-based 1
- Standard dosing ranges from 20-45mg/kg/day divided into appropriate intervals depending on infection severity 1
- For severe infections, higher doses (40-45mg/kg/day) are recommended 1
- The FDA-approved amoxicillin suspension should be shaken well before measuring each dose 1
Storage and Stability
- After reconstitution, amoxicillin suspension must be discarded after 14 days
- Refrigeration is preferable but not required
- Keep the bottle tightly closed when not in use 1
Common Pitfalls to Avoid
- Using incorrect measuring devices (household spoons)
- Failing to shake the suspension before measuring
- Miscalculating the dose by using the wrong concentration in the formula
- Not considering the maximum daily dose for the child's weight
Always verify calculations with another healthcare professional when possible, especially for pediatric medications where precision is critical.