Common Registration Assessment, Part 1
Hydroxychloroquine tablet strengths and weight-based maximums for the GPhC assessment
Three original practice questions, with the working shown. Read the stated prescription or plan before calculating.
Published 21 October 2026. Independent revision material, not GPhC questions, not for patient care.
The BNF lists hydroxychloroquine tablets in two strengths: 200 mg and 300 mg.
The BNF gives the usual adult dose as 200 mg to 400 mg a day, with the daily maximum based on ideal body weight, up to 6.5 mg per kg a day.
Each question fixes the values needed for its arithmetic. Write the unit beside every step and keep a single dose separate from a supply total. All prescriptions and patients here are fictional; these are revision materials, not for patient care.
The method
- Identify the exact strength, dose and frequency supplied in the question.
- Calculate one dose first; divide prescribed mg by mg per tablet.
- When a weight is given, multiply the per-kg maximum by the stated weight.
- Compare the prescribed daily dose with the calculated maximum.
- Check the tablet count is a whole number before reporting it.
Three practice questions
Work each one on paper first, then open the answer. All patients and prescriptions are fictional.
Question 1
A fictional prescription specifies hydroxychloroquine 200 mg once a day using 200 mg tablets for 28 days. How many tablets is the supply?
Show the answer
Answer: 28 tablets
Working: 200 ÷ 200 = 1 tablet a day. 1 × 28 = 28 tablets.
Question 2
A fictional patient has an ideal body weight of 60 kg. Using the BNF maximum of 6.5 mg per kg a day, what is the maximum daily dose, and does a fictional 400 mg daily prescription stay within it?
Show the answer
Answer: Maximum 390 mg a day, so 400 mg exceeds it
Working: 6.5 × 60 = 390 mg a day. 400 mg is 10 mg above the calculated maximum.
Question 3
A fictional prescription specifies hydroxychloroquine 400 mg once a day using 200 mg tablets for 30 days. How many tablets is the supply?
Show the answer
Answer: 60 tablets
Working: 400 ÷ 200 = 2 tablets a day. 2 × 30 = 60 tablets.
Exam approach
Maximum-dose questions are really two sums: work the dose, then test it against the cap. Show both before answering.
Where marks are lost
- Skipping the weight-based check when a weight is stated in the question.
- Mixing up the 200 mg and 300 mg strengths when the strength is stated in the question.
- Reporting a daily total when the question asks for a supply, or the other way round.
Frequently asked questions
Are these official assessment questions?
No. They are original revision exercises, not official GPhC questions and not for patient care.
Do I need to memorise the per-kg maximum?
The exercise supplies it. In the assessment, read any given product information exactly as written.
How should I check the answer?
Check the requested unit, then work backwards from the quantity to the stated dose and duration.
Sources
The questions above are original and use fictional patients and prescriptions. PreRegExamPrep is not affiliated with or endorsed by the General Pharmaceutical Council.
Practise until the method is automatic
Try 15 free questions with worked answers. No sign-up required.
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