Common Registration Assessment, Part 1
Mefenamic acid 500mg tablets and three daily doses for the GPhC assessment
Three original practice questions, with the working shown. Read the stated prescription or plan before calculating.
Published 5 November 2026. Independent revision material, not GPhC questions, not for patient care.
The manufacturer's UK product information for mefenamic acid 500 mg film-coated tablets states that the adult dose is one tablet (500 mg) three times daily.
The same information states that in menorrhagia the tablets are taken from the first day of excessive bleeding, and that in dysmenorrhoea they are taken at the onset of menstrual pain, in each case continued according to the judgement of the physician.
It also states that the tablets should be taken preferably with or after food.
Each question fixes the values needed for its arithmetic. Write the unit beside every step and distinguish a single dose from a daily total or a supply period. All prescriptions and patients here are fictional; these are revision materials, not for patient care.
The method
- Identify the dose per tablet and the number of doses each day.
- Multiply the tablet strength by the daily dose count for the daily milligram total.
- Multiply the daily tablet count by the stated number of days for a supply quantity.
- Keep milligrams and tablets separate; convert only when the question asks.
Three practice questions
Work each one on paper first, then open the answer. All patients and prescriptions are fictional.
Question 1
A fictional patient takes mefenamic acid 500 mg three times daily. How many milligrams is this each day?
Show the answer
Answer: 1,500 mg
Working: 500 mg x 3 doses each day = 1,500 mg a day.
Question 2
A fictional patient takes one mefenamic acid 500 mg tablet three times daily for 3 days, starting at the onset of pain. How many tablets is this in total?
Show the answer
Answer: 9 tablets
Working: 3 tablets each day x 3 days = 9 tablets.
Question 3
A fictional prescription for mefenamic acid 500 mg three times daily runs for 5 days. How many 500 mg tablets should be supplied?
Show the answer
Answer: 15 tablets
Working: 3 tablets each day x 5 days = 15 tablets.
eMC SmPC: Mefenamic Acid 500 mg film-coated Tablets
https://www.medicines.org.uk/emc/product/12503/smpc
Where marks are lost
- Counting only one tablet per day when the question states three doses daily.
- Treating the 500 mg tablet strength as the daily total.
- Forgetting to multiply the daily tablet count by the stated number of days.
Frequently asked questions
Are these official assessment questions?
No. They are original revision exercises, not official GPhC questions and not for patient care.
Does this calculation decide a real mefenamic acid dose?
No. Follow the stated prescription in the exercise. Real dosing checks include indication, duration and whether food is relevant.
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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