PSI Pharmaceutical Calculations 1 — Questions and Answers
Question 1: A patient requires amoxicillin 250 mg. The available suspension contains 125 mg/5 mL. What volume should be dispensed per dose?
- 5 mL
- 10 mL (Correct answer)
- 15 mL
- 20 mL
Correct answer: 10 mL
250 mg ÷ (125 mg/5 mL) = 10 mL per dose.
Question 2: A prescription states 'paracetamol 0.5 g'. Tablets available are 500 mg. How many tablets should be dispensed per dose?
- 0.5 tablet
- 1 tablet (Correct answer)
- 2 tablets
- 5 tablets
Correct answer: 1 tablet
0.5 g equals 500 mg, which is exactly one 500 mg tablet.
Question 3: A 2% w/v solution contains how many grams of solute in 250 mL?
- 0.5 g
- 2 g
- 5 g (Correct answer)
- 8 g
Correct answer: 5 g
2% w/v = 2 g per 100 mL; therefore 250 mL contains 2 × 2.5 = 5 g.
Question 4: A morphine injection contains 10 mg/mL. A patient requires a 15 mg dose. What volume should be drawn up?
- 0.5 mL
- 1.0 mL
- 1.5 mL (Correct answer)
- 2.0 mL
Correct answer: 1.5 mL
15 mg ÷ 10 mg/mL = 1.5 mL.
Question 5: Digoxin tablets are available as 62.5 micrograms. A patient requires 125 micrograms per dose. How many tablets should be given?
- 1 tablet
- 2 tablets (Correct answer)
- 3 tablets
- 4 tablets
Correct answer: 2 tablets
125 micrograms ÷ 62.5 micrograms = 2 tablets per dose.
Question 6: How many millilitres of a 1 in 1000 adrenaline solution are required to obtain a dose of 0.5 mg?
- 0.5 mL (Correct answer)
- 1.0 mL
- 2.0 mL
- 5.0 mL
Correct answer: 0.5 mL
A 1 in 1000 solution contains 1 g per 1000 mL = 1 mg/mL; therefore 0.5 mg requires 0.5 mL.
Question 7: A patient weighing 70 kg is prescribed a drug at a dose of 5 mg/kg. What is the total dose required?
- 70 mg
- 175 mg
- 350 mg (Correct answer)
- 500 mg
Correct answer: 350 mg
5 mg/kg × 70 kg = 350 mg total dose.
PSI Pharmaceutical Calculations 1
A patient requires amoxicillin 250 mg.
The available suspension contains 125 mg/5 mL.
What volume should be dispensed per dose?