Pharmacy Math A prescribed drug is available as a 275 syrup

Pharmacy Math.

A prescribed drug is available as a 2.75% syrup. The patient weighs 121 lbs. and has been ordered to take 5mg/kg q12h x10 days. If the solution is prepackaged in 6 fl oz. bottles with an attached oral dosing cup, how many bottles will be dispensed for this order?

How do you set this question up and what are the conversion factors? The answer listed is 2 bottles.

Solution

1) First we need to convert the weight into kg

1 lbs = 0.453592 Kg

121 lbs = 54.887 Kg

2) Now we need to calculate the required dosage

5mg per Kg

Hence for person weight 54.887 kg = 54.887 * 5 = 274.435 mg

3) Multiply dosage by frequency and duration

274.435 * 2 * 10 = 5488.7 mg

4) Hence the volume required will be 2.75% of syrup

2.75/100 * Volume = 5.4887

Volume = 548.87/(2.5) = 199.67 ml

5) One bottles contains 180ml of liquid

Let the bottles be x

Hence x = 199.67/180 = 1.123

Hence minimum number of bottles required are 2