Drug infusion rate

You are told to draw up a new inotrope for infusion to be administered to an 80 kg

patient. The drug comes as an ampoule containing 200mg in 20 mL. You are instructed

to draw the whole ampoule up with water for injection to make a final volume of

50 mL. You only have a basic syringe driver that runs in mL/h. The product information

recommends starting the infusion at 20 mcg/kg/min. How many mL/h would

you set the syringe driver to?

a) 9.6 mL/h

b) 12.0 mL/h

c) 16.7 mL/h

d) 18.0 mL/h

e) 24.0 mL/h

Answer: E

Explanation:

200mg in 50mL gives a concentration of 4mg/mL or 4000 mcg/mL.

1mL/h would be 50 mcg/kg/h or 50/60ths mcg/kg/min.

The required rate is therefore 20 ÷ 50/60 = 120/5 = 24 mL/h