Question

You want to give 5mg/kg of ampicillin Q8HR to a child weighing 65 pounds. If there is 25mg/ml on hand, how many mls will you give per dose?

Choose one answer.

a. 6 mls
b. 5.9 mls
c. 5.92 mls
d. 5.8 mls

Answer 1

To administer a
`5mg/kg` dose of ampicillin to a child weighing pounds, convert the weight to kilograms, calculate the total required milligrams, and then divide by the concentration in mg/ml. The answer is
`5.9 mls` per dose.

Step-by-step explanation:

To calculate how many mls of ampicillin you should administer per dose for a child that weighs
`65` pounds, you will first need to convert the weight to kilograms.
`65` in kilograms is 65
`lb ÷ 2.2 kg/lb = 29.55 kg`.

The prescribed dosage is 5mg/kg therefore the per dose amount in milligrams is
`5 mg/kg × 29.55 kg = 147.75 mg` .

Given that the medication is available at a concentration of
`25 mg/ml` you divide the per dose amount by the concentration to find the volume in milliliters:
`147.75 mg ÷ 25 mg/ml = 5.91 ml` .

You will round the final answer to the nearest tenth as per medical dosing standards, which in this case is
`5.9 ml`.
Therefore, the closest option is b.
`5.9 mls`.