Common Registration Assessment, Part 1

Rivastigmine patch strengths and the titration schedule for the GPhC assessment

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

Published 3 November 2026. Independent revision material, not GPhC questions, not for patient care.

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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 Exelon transdermal patches lists three release rates: 4.6 mg/24 h, 9.5 mg/24 h and 13.3 mg/24 h.

Treatment is started with 4.6 mg/24 h. After a minimum of four weeks, and if well tolerated, the dose should be increased to 9.5 mg/24 h, the recommended daily effective dose.

The same information allows an increase to 13.3 mg/24 h only after a minimum of six months at 9.5 mg/24 h in specific circumstances, and advises that if treatment is interrupted for more than three days it should be re-initiated with 4.6 mg/24 h.

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

The method

  1. Identify the exact patch strength stated in the question.
  2. One patch is applied each day; count days to count patches.
  3. Multiply the stated release rate by the number of days for the total released.
  4. Keep the four week and six month minimum periods straight before scheduling a step up.

Three practice questions

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

Question 1

A fictional patient applies one rivastigmine 4.6 mg/24 h patch each day. How much rivastigmine is released over 7 days?

Show the answer

Answer: 32.2 mg

Working: 4.6 mg x 7 days = 32.2 mg.

Question 2

A fictional patient starts on the 4.6 mg/24 h patch and stays on it for the minimum period before the dose can be increased. How many patches are used in that period?

Show the answer

Answer: 28 patches

Working: The minimum period is 4 weeks; 1 patch a day x 7 days x 4 weeks = 28 patches.

Question 3

A fictional plan uses the 4.6 mg/24 h patch for 4 weeks, then the 9.5 mg/24 h patch for the next 4 weeks. How many patches are needed in total?

Show the answer

Answer: 56 patches

Working: 4 weeks x 7 days = 28 patches at each strength; 28 + 28 = 56 patches.

eMC SmPC: Exelon 4.6 mg/24h transdermal patch

https://www.medicines.org.uk/emc/product/1185/smpc

Where marks are lost

  • Adding the three patch strengths together instead of reading the schedule as one patch a day.
  • Stepping up before the stated minimum period has passed.
  • 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 schedule calculation justify changing a real dose?

No. Follow the steps in the exercise. Real titration depends on tolerability and regular reassessment by the prescriber.

How should I check the answer?

Check the requested unit, then work backwards from the quantity to the stated rate 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.