Question

The doctor ordered Magnesium Sulfate 4gm IV to be given over 20 minutes. Magnesium Sulfate comes in 40gm/1000ml IV bottle. You would set your pump at _____ml/hour.  

Answer 1

Magnesium sulphate .

It is the drug which is used to replace the magnesium level in the body and also used to manage hypertension in pregnancy along with eclampsia.

Order.

Magnesium sulphate.

Dose= 4gm over 20 minutes.

Over 20 minutes means 4 gram magnesium sulphate should be administered for 20 min.

Availability= 40 gm / 1000 ml iv bottle.

To calculate the amount in ml.

Formula=

What we want / what we have * quantity of dilution.

Dose needed= 4 gm over 20 min.

Available dose= 40 gm.

Quantity of dilution= 1000 ml.

FORMULA CAN ALSO BE WRITTEN AS.

Dose needed / Dose on hand * Quantity of dilution.

= 4gm / 40 gm * 1000 ml.

= 100 ml.

So, 100 ml contains 4gm of magnesium sulphate that has to be administered over 20 min.

Flow rate = ( Total volume of drug / time in hour.)

Total volume = 1000 ml

To convert 20 mins into hour.

= 20 min / 60 min ( 1 hour)

= 0.3 hour

Flow rate = 1000 ml X 0.3 hr.

= 300 ml / hour.

Hence, 300 ml magnesium sulphate should be administered per hour.