Question

The prescriber has ordered 30 mg of Neo-Synephrine (phenylephrine) in dextrose 5%in water to infuse at a rate of 40 mcg per minute. The IV has a total volume of 250 mL. The nurse will infuse the IV at how many mL per hour?

Answer 1

First lets put together all the information we have

Dose of the drug to be given = 30 mg

Total volume of the IV Solution ie; Dextrose (5%) = 250 ml

Infusion rate = 40 mcg/min

Infusion rate ( in ml/hr) = To find.

Solution

Lets begin by converting 30mg to mcg........

1mg = 1000 mcg

Hence 30 mg = 30,000 mcg.

Since 30,000mcg is diluted in 250 ml of 5% dextrose;

1 ml dextrose has 30,00/250 = 120 mcg of drug.

Hence the volume of dextrose that will have 40 mcg concentration of drug = 40/120 = 0.33ml

40mcg/ min was the infusion rate given , which we have found out is 0.33ml/min.

To covert it into hours , we multiply it by 60 ( 1 hr is 60 minutes) = 0.33 x 60 = 20ml / hr.

Therefore, the infusion rate needed is 20ml / hr.