Question

The doctor wants to give a dose of amoxicillin 200 mg bid to a 4 year old female. you have amoxicillin 250 mg/5 ml in 100 ml bottles. what would the dose be in ml?

Answer 1

To compute for the volume, we must multiply the desired dose (200 mg) of the drug to the reciprocal of the concentration of the preparation (200 mg/5mL).

The computation is as follows:

$Volume = (200 mg)( \frac{5 mL}{250 mg})$
$Volume = 4 mL$

Therefore the dose of Amoxicillin in this case is 4 mL twice a day or BID. 

Answer 2

Amoxicillin is an antibiotic from the penicillin family. Patients that have been prescribed amoxicillin should respect the dosage:
In this case, we have 100ml of amoxicillin in a concentration of 250mg/5ml, and the patient needs 200mg her treatment, so you should do a cross multiplication:
250mg ==> 5ml
200mg ==> x
X = 200*5 / 250 = 4ml