Common Registration Assessment, Part 1

Granisetron tablet doses and patch wear days 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 chemotherapy treatment room with two chairs and infusion stands
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 Kytril (granisetron) tablets states that the dose is 1 mg twice a day or 2 mg once a day for up to one week following radiotherapy or chemotherapy, and that the first dose should be administered within 1 hour before the start of therapy.

The manufacturer's UK product information for the Sancuso 3.1 mg/24 hours transdermal patch states that a single patch is applied 24 to 48 hours before chemotherapy, removed a minimum of 24 hours after completion of chemotherapy, and can be worn for up to 7 days depending on the duration of the chemotherapy regimen.

The two products cover the same ground in different units: tablets in mg per day and days of treatment, the patch in mg per 24 hours and days of wear.

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

The method

  1. Identify whether the stated product is the tablet or the patch.
  2. For tablets, multiply the stated daily mg by the stated days; divide by the tablet strength for the count.
  3. For the patch, add the stated days before chemotherapy, the chemotherapy days and the stated days after for the total wear, and check it against 7 days.
  4. Keep mg, mg per 24 hours, tablets, patches 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 patient takes granisetron 2 mg once a day for up to one week following chemotherapy, using 1 mg tablets. How many tablets are taken each day, and how many over 7 days?

Show the answer

Answer: 2 tablets daily; 14 tablets

Working: 2 mg / 1 mg = 2 tablets daily. 2 x 7 days = 14 tablets.

Question 2

A fictional patient takes granisetron 1 mg twice a day following radiotherapy, using 1 mg tablets. What is the total daily dose in mg?

Show the answer

Answer: 2 mg

Working: 1 mg x 2 doses daily = 2 mg daily, the same daily total as the 2 mg once-daily option.

Question 3

A fictional patient applies a Sancuso patch 48 hours before a 3-day chemotherapy course and removes it 24 hours after the course ends. How many days is the patch worn, is that within the label maximum, and using the printed 3.1 mg/24 hours, how much granisetron is delivered over the wear time?

Show the answer

Answer: 6 days; within the 7-day maximum; 18.6 mg

Working: 2 days before + 3 days of chemotherapy + 1 day after = 6 days, within the label's up-to-7-days wear. 6 x 3.1 mg = 18.6 mg.

eMC SmPC: Kytril 1 mg film-coated tablets

https://www.medicines.org.uk/emc/product/12777/smpc

Where marks are lost

  • Applying the tablet regimen to the patch; the patch is a single application, not a daily dose.
  • Counting only the chemotherapy days for patch wear; the patch goes on 24 to 48 hours before and stays at least 24 hours after.
  • Forgetting that 2 mg once daily needs two 1 mg tablets each day, not one.

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 granisetron regimen?

No. Follow the stated regimen in the exercise. Real antiemetic cover follows the chemotherapy plan, with the first tablet dose within an hour before therapy.

How should I check the answer?

Keep tablets and patches separate: tablets in mg per day and days, the patch in days of wear and 3.1 mg per 24 hours.

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.