Calculating Amoxicillin Volume for a 200 mg Dose
You should administer 4 mL of the amoxicillin suspension.
The Calculation
This is a straightforward dosing calculation using the concentration provided:
- Ordered dose: 200 mg
- Available concentration: 50 mg/mL
- Formula: Volume (mL) = Dose needed (mg) ÷ Concentration (mg/mL)
- Calculation: 200 mg ÷ 50 mg/mL = 4 mL
Clinical Context for Amoxicillin Dosing
While this question asks for a simple volume calculation, it's worth noting the clinical appropriateness of a 200 mg dose:
- Pediatric dosing: For streptococcal pharyngitis, amoxicillin is typically dosed at 25–50 mg/kg/day divided into 1–2 doses, with a maximum of 1000 mg per dose 1
- Adult dosing: Standard adult doses for streptococcal infections are 500 mg twice daily for 10 days 1
- A 200 mg dose would be appropriate for a small child (approximately 4–8 kg if using 25–50 mg/kg/day dosing) or as part of a divided daily regimen 1
Verification Steps
Always double-check medication calculations:
- Verify the order: Confirm 200 mg is the intended dose
- Check the concentration: Ensure the suspension is indeed 50 mg/mL (this should be clearly labeled on the bottle after reconstitution) 2
- Calculate: 200 ÷ 50 = 4 mL
- Use appropriate measuring device: Use an oral syringe or calibrated dosing cup for accurate measurement
Common Pitfalls to Avoid
- Do not confuse the concentration before and after reconstitution—amoxicillin powder must be mixed with water according to package directions to achieve the stated concentration 2
- Shake the suspension well before each dose, as amoxicillin suspensions can settle 2
- Refrigerate reconstituted suspension and discard after 14 days 2