Common Registration Assessment, Part 1

Minocycline MR capsules and acne course lengths for the GPhC assessment

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

Published 13 November 2026. Independent revision material, not GPhC questions, not for patient care.

A woman gently framing her face with both hands, skincare concept
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 for Minocin MR (minocycline) 100 mg modified-release capsules gives one 100 mg capsule every 24 hours for adults.

For acne, the same information states treatment should continue for a minimum of six weeks and, where possible, be limited to a maximum of six months.

It also states the capsules should be swallowed whole with plenty of fluid while sitting or standing.

Each question fixes the values needed for its arithmetic. Every answer is a once-daily count; check the schedule before multiplying. All prescriptions and patients here are fictional; these are revision materials, not for patient care.

The method

  1. Use one 100 mg capsule every 24 hours; never twice daily.
  2. Convert course lengths in weeks to days by multiplying by seven.
  3. Check the stated course against the six-week minimum and six-month maximum for acne.
  4. Keep the modified-release instruction in mind: swallow whole, do not open or chew.

Three practice questions

Work each one on paper first, then open the answer. All patients and prescriptions are fictional.

Question 1

A fictional adult is prescribed Minocin MR 100 mg once daily for the printed minimum acne course. How many capsules does the course need?

Show the answer

Answer: 42 capsules

Working: The minimum acne course is six weeks. 6 x 7 = 42 days, and one capsule a day gives 42 capsules.

Question 2

A fictional adult is prescribed Minocin MR 100 mg once daily for 12 weeks. How many capsules does the course need?

Show the answer

Answer: 84 capsules

Working: 12 x 7 = 84 days, and one capsule a day gives 84 capsules.

Question 3

A fictional adult is prescribed Minocin MR 100 mg once daily for the printed maximum acne course. Using a working assumption of 26 weeks for six months, how many capsules does the course need?

Show the answer

Answer: 182 capsules, on that working assumption

Working: 26 x 7 = 182 days, and one capsule a day gives 182 capsules. The product information states a maximum of six months rather than a day count, so 26 weeks is a working assumption.

eMC SmPC: Minocin MR 100 mg Modified Release Capsules

https://www.medicines.org.uk/emc/product/9519/smpc

Where marks are lost

  • Dosing twice daily when the modified-release capsule is taken once every 24 hours.
  • Stopping before the printed six-week minimum for acne.
  • Opening or chewing the modified-release capsule instead of swallowing it whole.

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 dose?

No. Follow the stated prescription in the exercise. Real dosing follows the prescriber and the product information for the named product.

How should I check the answer?

One capsule per 24 hours; convert the stated weeks to days by multiplying by seven, then check the six-week minimum and six-month maximum.

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.

More calculation topics

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