Common Registration Assessment, Part 1

Celecoxib 100 mg and 200 mg capsules and daily doses for the GPhC assessment

Three original practice questions, with the working shown. Read the stated prescription or plan before calculating.

Published 2 November 2026. Independent revision material, not GPhC questions, not for patient care.

Two blue capsules on a round white platform
Photo from Pexels, used under the Pexels licence. It is a stock image and does not show the exercise.

The manufacturer's UK product information lists celecoxib capsules in 100 mg and 200 mg strengths.

For osteoarthritis, that product information recommends 200 mg once a day or in two divided doses; for rheumatoid arthritis, an initial 200 mg a day in two divided doses, increasing to 200 mg twice a day if needed.

The same information sets a maximum recommended daily dose of 400 mg for all indications and advises using the lowest effective dose for the shortest time.

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 course supply. All prescriptions and patients here are fictional; these are revision materials, not for patient care.

The method

  1. Identify the exact strength and frequency stated in the question.
  2. Double a twice daily dose to get the daily total before scaling up.
  3. Work out how many capsules make each stated dose from the given strength.
  4. Compare the daily total against the stated 400 mg maximum only when the question asks.
  5. Keep milligrams and capsules separate; convert only if 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 celecoxib 100 mg twice a day for osteoarthritis. How many milligrams a day is that, and how many capsules is a 30-day supply?

Show the answer

Answer: 200 mg a day; 60 capsules

Working: 100 mg x 2 doses = 200 mg a day; 2 capsules x 30 days = 60 capsules.

Question 2

A fictional patient takes 200 mg once a day for 28 days. How many capsules and how many milligrams is the supply?

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Answer: 28 capsules; 5,600 mg

Working: 1 capsule x 28 days = 28 capsules; 200 mg x 28 days = 5,600 mg.

Question 3

A fictional patient with rheumatoid arthritis is increased to 200 mg twice a day. Is this within the stated maximum daily dose, and how many milligrams a day is it?

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Answer: 400 mg a day; yes, it equals the stated 400 mg maximum

Working: 200 mg x 2 doses = 400 mg a day; 400 mg equals the stated maximum recommended daily dose.

eMC SmPC: Celecoxib 100 mg capsules

https://www.medicines.org.uk/emc/product/2117/smpc

Where marks are lost

  • Reporting the single dose instead of the daily total for a twice daily schedule.
  • Mixing 100 mg and 200 mg capsules in the same line of working.
  • Treating arithmetic as evidence that a real prescription is clinically suitable.

Frequently asked questions

Are these official assessment questions?

No. They are original revision exercises, not official GPhC questions and not for patient care.

Can a dose-total calculation justify changing a real dose?

No. Follow the steps in the exercise. Real dose changes are gradual and need clinical checks.

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.

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More calculation topics

See also the formula sheet, the eight sample questions and the approved calculator page.