CSPT Compounding Calculations 3

Question 1

A compounded IV bag contains 3 g of vancomycin in 300 mL NS. What is the concentration in mg/mL?

Accepted Answer

10 mg/mL

Answer

3 g = 3000 mg; 3000 mg ÷ 300 mL = 10 mg/mL.

Question 2

A prescription requires 120 mL of a solution containing 15 mg/mL of drug X. How many grams of drug X are needed?

Accepted Answer

1.8 g

Answer

120 mL × 15 mg/mL = 1800 mg = 1.8 g.

Question 3

An insulin drip is running at 8 mL/hr. The bag contains 100 units in 100 mL NS. How many units per hour is the patient receiving?

Accepted Answer

8 units/hr

Answer

Concentration = 100 units/100 mL = 1 unit/mL; 8 mL/hr × 1 unit/mL = 8 units/hr.

Question 4

You need to prepare 200 mL of a 10% solution using pure drug powder. How much powder (in grams) is required?

Accepted Answer

20 g

Answer

10% w/v = 10 g/100 mL; for 200 mL: 10 × 2 = 20 g.

Question 5

A patient weighs 154 lbs. A drug is dosed at 2 mg/kg. What is the total dose in mg?

Accepted Answer

140 mg

Answer

154 lbs ÷ 2.2 = 70 kg; 70 kg × 2 mg/kg = 140 mg.

CSPT - Compounded Sterile Preparation Technician Practice Test