Common Registration Assessment, Part 1

Nabilone capsule strengths and twice-daily doses for the GPhC assessment

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

Published 10 November 2026. Independent revision material, not GPhC questions, not for patient care.

A hand holding a yellow and white capsule
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 nabilone 1 mg capsules states that nabilone is for administration to adults only, and that the usual adult dosage is 1 mg or 2 mg twice a day, with the lower starting dose recommended to minimise side-effects.

The same information states that the first dose should be administered the evening before the start of chemotherapy, that the second dose should be given one to three hours before the first dose of the oncolytic agent, and that the maximum daily dose should not exceed 6 mg, given in three divided doses.

It also states that nabilone may be administered throughout each cycle of chemotherapy and, if necessary, for 48 hours after the last dose of each cycle.

Each question fixes the values needed for its arithmetic. Write the unit beside every step and distinguish a single dose from a daily total. All prescriptions and patients here are fictional; these are revision materials, not for patient care.

The method

  1. Read the stated dose per administration and the twice-daily frequency.
  2. Multiply the dose by two for the daily total, and check it against the 6 mg daily maximum.
  3. Multiply the daily capsule count by the stated days for a course quantity.
  4. Keep mg per dose, mg per day, capsules and days 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 adult starts nabilone at the label lower dose of 1 mg twice a day, using 1 mg capsules. How many capsules are taken each day?

Show the answer

Answer: 2 capsules

Working: 1 mg per dose x 2 doses daily = 2 mg daily = 2 capsules daily.

Question 2

A fictional adult takes nabilone 2 mg twice a day throughout a 5-day chemotherapy course, using 1 mg capsules. How many capsules are needed for the course?

Show the answer

Answer: 20 capsules

Working: 2 mg x 2 doses daily = 4 mg daily = 4 capsules daily. 4 x 5 days = 20 capsules.

Question 3

A fictional patient is prescribed the label maximum daily dose of nabilone, given in three divided doses. What is the maximum daily dose, and how much is given per administration?

Show the answer

Answer: 6 mg daily; 2 mg per administration

Working: The label maximum is 6 mg per day in three divided doses. 6 / 3 = 2 mg per administration.

eMC SmPC: Nabilone 1mg Capsule

https://www.medicines.org.uk/emc/product/12767/smpc

Where marks are lost

  • Counting one capsule per dose at the 2 mg twice-daily regimen; with 1 mg capsules each dose needs two capsules.
  • Exceeding 6 mg in a day when spreading doses; 6 mg in three divided doses is the label maximum.
  • Starting the first dose with chemotherapy; the label gives it the evening before, with the next dose one to three hours before the first oncolytic dose.

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 nabilone dose?

No. Follow the stated prescription in the exercise. Real dosing starts low to minimise side-effects and is increased as needed, up to the label maximum.

How should I check the answer?

Multiply the single dose by the stated daily doses for the daily total, then by the stated days for the course count.

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.