CETP Pharmaceutical Calculations 1 — Questions and Answers
Question 1: A patient is prescribed amoxicillin 250 mg/5 mL oral suspension. The prescribed dose is 125 mg three times daily. How many mL should be administered per dose?
- 1.5 mL
- 2.5 mL (Correct answer)
- 5.0 mL
- 7.5 mL
Correct answer: 2.5 mL
125 mg ÷ (250 mg/5 mL) = 125 ÷ 50 mg/mL = 2.5 mL per dose.
Question 2: A physician orders 1 L of normal saline to be infused over 8 hours. What is the correct infusion rate in mL/hr?
- 100 mL/hr
- 125 mL/hr (Correct answer)
- 150 mL/hr
- 200 mL/hr
Correct answer: 125 mL/hr
1000 mL ÷ 8 hours = 125 mL/hr.
Question 3: What is the percentage strength (w/v) of a solution containing 5 g of sodium chloride dissolved in enough water to make 200 mL?
- 0.25%
- 1.0%
- 2.5% (Correct answer)
- 5.0%
Correct answer: 2.5%
Percentage w/v = (5 g ÷ 200 mL) × 100 = 2.5%.
Question 4: A child weighs 22 lbs. The prescribed antibiotic dose is 10 mg/kg/day in two equally divided doses. How many mg should be given per dose?
- 25 mg
- 50 mg (Correct answer)
- 100 mg
- 200 mg
Correct answer: 50 mg
22 lbs ÷ 2.2 = 10 kg; 10 kg × 10 mg/kg/day = 100 mg/day ÷ 2 doses = 50 mg per dose.
Question 5: How many grams of dextrose are contained in 500 mL of D5W (5% dextrose in water)?
- 5 g
- 25 g (Correct answer)
- 50 g
- 100 g
Correct answer: 25 g
5% w/v = 5 g per 100 mL; 500 mL × 5 g/100 mL = 25 g of dextrose.
Question 6: A preparation is labeled as a 1:500 ratio strength solution. What is this expressed as a percentage strength?
- 0.02%
- 0.2% (Correct answer)
- 2%
- 5%
Correct answer: 0.2%
1:500 = 1 g per 500 mL = 0.2 g per 100 mL = 0.2%.
Question 7: A patient is prescribed metformin 1 g twice daily. Metformin tablets are available as 500 mg. How many tablets are required per day?
- 1 tablet
- 2 tablets
- 4 tablets (Correct answer)
- 8 tablets
Correct answer: 4 tablets
1 g = 1000 mg; 1000 mg ÷ 500 mg/tablet = 2 tablets per dose × 2 doses/day = 4 tablets/day.
CETP Pharmaceutical Calculations 1
A patient is prescribed amoxicillin 250 mg/5 mL oral suspension.
The prescribed dose is 125 mg three times daily.
How many mL should be administered per dose?