CSPT Sterile Compounding Calculations 4 — Questions and Answers
Question 1: A pharmacist orders vancomycin 1250 mg in 500 mL NS to infuse over 90 minutes. What is the infusion rate in mL/hr?
- 250 mL/hr
- 333 mL/hr (Correct answer)
- 500 mL/hr
- 167 mL/hr
Correct answer: 333 mL/hr
500 mL ÷ 1.5 hr = 333 mL/hr.
Question 2: A TPN requires 50 g of dextrose. How many mL of D70W (70% dextrose) are needed?
- 50 mL
- 71.4 mL (Correct answer)
- 100 mL
- 35 mL
Correct answer: 71.4 mL
50 g ÷ 0.7 g/mL = 71.4 mL.
Question 3: A 1-liter bag of NS is infusing via gravity at 20 gtt/min with a 15 gtt/mL drip set. What is the infusion rate in mL/hr?
- 60 mL/hr
- 80 mL/hr (Correct answer)
- 90 mL/hr
- 100 mL/hr
Correct answer: 80 mL/hr
20 gtt/min ÷ 15 gtt/mL × 60 min/hr = 80 mL/hr.
Question 4: You are making a preparation requiring 0.8% benzalkonium chloride. How many mg are needed for 50 mL?
- 4 mg
- 40 mg
- 400 mg (Correct answer)
- 0.4 mg
Correct answer: 400 mg
0.8% = 0.8 g/100 mL = 0.4 g/50 mL = 400 mg.
Question 5: An antibiotic IVPB contains 750 mg in 100 mL. A dose of 500 mg is prescribed. How many mL should be administered?
- 50 mL
- 66.7 mL (Correct answer)
- 75 mL
- 100 mL
Correct answer: 66.7 mL
500 mg ÷ (750 mg/100 mL) = 66.7 mL.
Question 6: A solution of calcium gluconate 10% contains how many mg/mL of calcium gluconate?
- 10 mg/mL
- 100 mg/mL (Correct answer)
- 1 mg/mL
- 50 mg/mL
Correct answer: 100 mg/mL
10% = 10 g/100 mL = 100 mg/mL.
Question 7: A compounded preparation calls for 1:10,000 epinephrine. What is the concentration in mcg/mL?
- 0.1 mcg/mL
- 1 mcg/mL
- 10 mcg/mL
- 100 mcg/mL (Correct answer)
Correct answer: 100 mcg/mL
1:10,000 = 0.1 mg/mL = 100 mcg/mL.
CSPT Sterile Compounding Calculations 4
A pharmacist orders vancomycin 1250 mg in 500 mL NS to infuse over 90 minutes.
What is the infusion rate in mL/hr?