Pharmacy Technician PTCB Pharmacy Calculations 2 — Questions and Answers
Question 1: An IV order calls for 1,000 mL of normal saline to infuse over 8 hours. What is the infusion rate in mL/hr?
- 100 mL/hr
- 125 mL/hr (Correct answer)
- 150 mL/hr
- 75 mL/hr
Correct answer: 125 mL/hr
1,000 mL ÷ 8 hours = 125 mL/hr infusion rate.
Question 2: Using a 15 gtt/mL drip set at 125 mL/hr, what is the drip rate in drops per minute?
- 15 gtt/min
- 31 gtt/min (Correct answer)
- 21 gtt/min
- 42 gtt/min
Correct answer: 31 gtt/min
125 mL/hr × 15 gtt/mL ÷ 60 min/hr = 31.25 ≈ 31 gtt/min.
Question 3: A solution is labeled 1:500. What is the equivalent percentage strength?
- 0.5%
- 5%
- 0.2% (Correct answer)
- 2%
Correct answer: 0.2%
1:500 means 1 g per 500 mL; (1 ÷ 500) × 100 = 0.2% w/v.
Question 4: A patient weighs 154 lbs. What is their weight in kilograms?
- 70 kg (Correct answer)
- 77 kg
- 68 kg
- 80 kg
Correct answer: 70 kg
154 lbs ÷ 2.2 lbs/kg = 70 kg.
Question 5: A drug is dosed at 5 mg/kg. For a 70 kg patient, what is the correct dose?
- 350 mg (Correct answer)
- 700 mg
- 14 mg
- 500 mg
Correct answer: 350 mg
5 mg/kg × 70 kg = 350 mg.
Question 6: A 2% w/v solution contains how many grams of drug per 100 mL?
- 0.2 g
- 20 g
- 2 g (Correct answer)
- 200 mg
Correct answer: 2 g
A 2% w/v solution by definition contains 2 g of solute per 100 mL of solution.
Question 7: Using alligation, how many mL of a 70% solution are needed to prepare 100 mL of a 40% solution using a 70% and a 10% solution?
- 50 mL (Correct answer)
- 60 mL
- 30 mL
- 40 mL
Correct answer: 50 mL
Alligation: 40−10=30 parts of 70%; 70−40=30 parts of 10%; 30/60 × 100 = 50 mL of 70% solution.
Pharmacy Technician PTCB Pharmacy Calculations 2
An IV order calls for 1,000 mL of normal saline to infuse over 8 hours.
What is the infusion rate in mL/hr?