CSPT Sterile Compounding Calculations 5 — Questions and Answers
Question 1: A dopamine drip is ordered at 5 mcg/kg/min for a 70 kg patient. The bag contains 400 mg in 250 mL. What is the infusion rate in mL/hr?
- 8.2 mL/hr
- 13.1 mL/hr (Correct answer)
- 16.4 mL/hr
- 20 mL/hr
Correct answer: 13.1 mL/hr
5 mcg/kg/min × 70 kg = 350 mcg/min; 400 mg/250 mL = 1.6 mg/mL = 1600 mcg/mL; 350 mcg/min ÷ 1600 mcg/mL × 60 = 13.1 mL/hr.
Question 2: How many mL of sterile water are needed to reconstitute a 1 g vial of cefazolin to achieve a concentration of 100 mg/mL?
- 5 mL
- 10 mL (Correct answer)
- 20 mL
- 100 mL
Correct answer: 10 mL
1 g = 1000 mg; 1000 mg ÷ 100 mg/mL = 10 mL.
Question 3: A TPN requires 60 mEq of magnesium sulfate. Magnesium sulfate is available as 50% (4 mEq/mL). How many mL are needed?
- 7.5 mL
- 15 mL (Correct answer)
- 30 mL
- 60 mL
Correct answer: 15 mL
60 mEq ÷ 4 mEq/mL = 15 mL.
Question 4: An IV bag labeled '2 mg/mL' morphine must deliver 0.05 mg/kg/hr to a 60 kg patient. What rate in mL/hr is required?
- 0.5 mL/hr
- 1.5 mL/hr (Correct answer)
- 3 mL/hr
- 6 mL/hr
Correct answer: 1.5 mL/hr
0.05 mg/kg/hr × 60 kg = 3 mg/hr; 3 mg/hr ÷ 2 mg/mL = 1.5 mL/hr.
Question 5: A 250 mL NS bag contains 500 mg of ciprofloxacin. After 100 mL has infused, how many mg of drug remain in the bag?
- 100 mg
- 200 mg
- 300 mg (Correct answer)
- 400 mg
Correct answer: 300 mg
500 mg ÷ 250 mL = 2 mg/mL; 150 mL remain × 2 mg/mL = 300 mg.
Question 6: What volume of a 40 mEq/20 mL KCl vial should be added to a bag to deliver 20 mEq of potassium?
- 5 mL
- 10 mL (Correct answer)
- 15 mL
- 20 mL
Correct answer: 10 mL
40 mEq/20 mL = 2 mEq/mL; 20 mEq ÷ 2 mEq/mL = 10 mL.
Question 7: A beyond-use date (BUD) policy allows 12 hours at room temperature for a sterile preparation. If compounding is completed at 09:30, what is the latest BUD time?
- 19:30
- 21:30 (Correct answer)
- 21:00
- 09:30 the next day
Correct answer: 21:30
09:30 + 12 hours = 21:30.
CSPT Sterile Compounding Calculations 5
A dopamine drip is ordered at 5 mcg/kg/min for a 70 kg patient.
The bag contains 400 mg in 250 mL.
What is the infusion rate in mL/hr?