Med Math: Drop Factors Question #20


Dopamine is ordered at 20 mcg/kg/min and the bag on hand is labeled 100 mg/50 mL. The client weighs 88 lbs. Calculate the rate/hr.


  1. 22 mL/hr
    • Rationale:
  2. 12 mL/hr
    • Rationale:
  3. 16 mL/hr
    • Rationale:
  4. 24 mL/hr
    • Rationale:



Dopamine is ordered in a bag of 100 mg/50ml. The nurse needs to find the mcg per minute in order to solve the problem. Step 1- Convert given wt. of Lbs to Kg by dividing by 2.2. As the Kg does not match in both the stem and scenario. 88 Lbs divided by 2.2 equals 40 kg. The problem will now look similar to the original dosage problem such as 20 mcg/ 40 kg/min. Another way to look at the problem is to think that a 40 kg client is getting 20mcg of medicine per minute.

nSTEP 2- Convert 100 mg to mcg. Move the decimal 3 places to the left. You now have 100,000 mcg of medicine. STEP 3 – Multiply appropriate wt. calculated by the dose of 20 mcg then multiple again by volume of 50 ml and times expressed in 60 mins.Then divide by the ordered dose or what you have which is 100,000 mcg.

STEP 4 – Round the answer accordingly to a whole number. There is a simple formula below for calculating the dose to be given. The final answer should have ml/hr within.

Dose ordered x weight (if weight based) x volume x time



20 mcg/kg/min x 40 kg (convert lbs to kg) x 50 mL x 60 min / 100,000 mcg/mL = 2,400,000/100,000 = 24 ml/hr

Learning Outcomes

Test Taking Tip

Video Rationale