Pharmacology math question

Question

You are setting up an isuprel drip for your 45 lb pediatric patient suffering from refractory

bronchospasm. The doctor has ordered 0.1 mcg/kg/min. the vial is labeled 1mg/5mL. You have a 250 mL bag

of D5W and a microdrip set (60 gtt/mL. What is your drip rate to achieve the doctor’s order

Answer 1

First we want to convert 45 lbs to kgs

45 lb ÷ 2.2 ≡ 20.4 kg

Then calculate the dosage for this child

0.1 mcg × 20.4kg ≡ 2.04 mcg/min

This is the rate per minute. So now we will calculate the rate per hour.

2.04 × 60 ≡ 122.4 mcg/hr

Then we can convert mcg to mg ( divide by 1000)

122.4 ÷ 1000 = 0.1224 mg/hr

Using formula: ordered per hour ÷ Have x Volume (ml) = Flow rate in ml/hr

0.1224mg/hr ÷ 1 mg (the vial) x 250ml/hr = 30.6 ml/hr

Then calculate IV drip rate using formula: volume (ml) ÷ time (min) x drop factor (gtts/mL) = Y (Flow rate in gtts/mins)

30.6 ÷ 60 x 60 = 30.6 gtts/min

The answer becomes 30.6gtts/min

*The 60 (mins) and the 60 (flow rate) will cancel each other out*