Common Registration Assessment, Part 1

Irbesartan 75mg, 150mg and 300mg daily doses for the GPhC assessment

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

Published 6 November 2026. Independent revision material, not GPhC questions, not for patient care.

A clinician measuring a patient's blood pressure with an arm cuff
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 irbesartan 150 mg film-coated tablets states that the usual recommended initial and maintenance dose is 150 mg once daily, with or without food.

The same information states that initiation of therapy with 75 mg could be considered, particularly in haemodialysed patients and in the elderly over 75 years.

It also states that in patients insufficiently controlled with 150 mg once daily, the dose can be increased to 300 mg, or other antihypertensive agents can be added.

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 a supply period. All prescriptions and patients here are fictional; these are revision materials, not for patient care.

The method

  1. Identify the stated daily dose in milligrams and the tablet strength supplied.
  2. Divide the daily dose by the tablet strength to count tablets per day.
  3. Multiply the daily dose or tablet count by the stated number of days for a total.
  4. Keep milligrams and tablets 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 irbesartan 150 mg once daily. How many milligrams is this over 30 days?

Show the answer

Answer: 4,500 mg

Working: 150 mg each day x 30 days = 4,500 mg in total.

Question 2

A fictional patient's dose is increased to 300 mg once daily using 150 mg tablets. How many tablets are needed for a 28-day supply?

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Answer: 56 tablets

Working: 300 mg / 150 mg per tablet = 2 tablets each day. 2 tablets x 28 days = 56 tablets.

Question 3

A fictional patient aged 78 starts irbesartan at 75 mg once daily. How many milligrams do they take in the first week?

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Answer: 525 mg

Working: 75 mg each day x 7 days = 525 mg in the first week.

eMC SmPC: Aprovel 150mg film-coated tablets

https://www.medicines.org.uk/emc/product/3050/smpc

Where marks are lost

  • Using 150 mg for every patient when the question states a 75 mg start, such as in haemodialysis or in an elderly patient over 75.
  • Forgetting that 300 mg once daily with 150 mg tablets means 2 tablets each day before multiplying by the number of days.
  • Mixing up milligrams and tablets when the question asks for a supply quantity.

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 irbesartan dose?

No. Follow the stated prescription in the exercise. Real dosing depends on blood pressure response and factors such as dialysis and age.

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.