Help with medication dosage calculations!

Question

A neonate weighs 6.6 lbs. She is ordered a medication dose of 20 mg/kg every 12 hours. The medication is available in a concentration of 25 mg/ml. How many ml will the infant require per 12 hours?

Answer 1

Always look at what is being asked and what info is being given to you. Often you will need to convert units to make sure you are working with the same units and not mixing apples and oranges! Convert the patient's weight to kg first, then multiply by the mg/kg dose. Kg will cancel out and you will be left with the mg dose needed. Last step- figure out how many ml of the available product will give you the right dose.

1. Since 1 kg = 2.2 lbs, 6.6 lbs divided by 2.2 gives you weight of 3 kg.
2. If dose is 20mg per 1 kg, a patient who weighs 3 kg will need three times that, or 60 mg
3. The product available is 25 mg per 1 ml, so you would do a proportion to find that 60 mg = 2.4 ml.

And there's your answer! It just takes practice.

Be consistent, watch your units, and be sure you are giving your answer in the units they asked for!