Common Registration Assessment, Part 1

Lercanidipine 10 mg and 20 mg tablets and morning 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.

Tablets beside a glass of water on a wooden table
Photo from Pexels, used under the Pexels licence. It is a stock image and does not show the exercise.

The NHS describes lercanidipine as a medicine used to treat high blood pressure.

The manufacturer's UK product information lists 10 mg and 20 mg film-coated tablets, with a recommended dose of 10 mg once a day taken at least 15 minutes before a meal.

The same product information says the dose can be increased to 20 mg once a day depending on response, with gradual titration because the full effect can take about 2 weeks to appear.

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. Count one tablet per day for each tablet taken once a day before scaling to the stated period.
  3. Calculate one day first, then scale to the stated number of days or weeks.
  4. Convert weeks into days by multiplying by 7 before counting doses.
  5. Keep milligrams and tablets 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 lercanidipine 10 mg once a day in the morning. How many tablets and how many milligrams is a 28-day supply?

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Answer: 28 tablets; 280 mg

Working: 1 tablet x 28 days = 28 tablets; 10 mg x 28 days = 280 mg.

Question 2

A fictional patient takes 10 mg once a day for 2 weeks, then 20 mg once a day for the next 2 weeks. How many milligrams is the full 4 weeks?

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Answer: 420 mg

Working: (10 mg x 14 days) + (20 mg x 14 days) = 140 mg + 280 mg = 420 mg.

Question 3

A fictional prescription reads lercanidipine 20 mg once a day using 10 mg tablets. How many tablets should be supplied for 30 days?

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Answer: 60 tablets

Working: 20 mg / 10 mg = 2 tablets a day; 2 tablets x 30 days = 60 tablets.

NHS: Lercanidipine

https://www.nhs.uk/medicines/lercanidipine/

Where marks are lost

  • Counting a once daily tablet more than once in a day.
  • Reporting milligrams when the question asks for a tablet count.
  • 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.