Common Registration Assessment, Part 1

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

A white medicine bottle with capsules on a beige surface
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 Pradaxa hard capsules recommends 300 mg dabigatran etexilate a day, taken as one 150 mg capsule twice daily, for prevention of stroke and systemic embolism in adults with non-valvular atrial fibrillation who have one or more risk factors.

The same information recommends a daily dose of 220 mg, taken as one 110 mg capsule twice daily, for patients aged 80 years or above and for patients who receive concomitant verapamil.

Pradaxa capsules are also used for primary prevention of venous thromboembolism after elective hip or knee replacement surgery, with doses and durations set out in the product information.

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

The method

  1. Identify the exact capsule strength and frequency stated in the question.
  2. Double a twice daily dose to get the daily total before scaling up.
  3. Count one capsule per stated dose, then multiply by the number of doses.
  4. Multiply the daily capsule count by the stated number of days for a supply quantity.
  5. Keep milligrams and capsules 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 dabigatran 150 mg twice a day. How many milligrams is the daily total?

Show the answer

Answer: 300 mg

Working: 150 mg x 2 doses = 300 mg a day.

Question 2

A fictional patient aged 82 takes dabigatran 110 mg twice a day. How many milligrams is the daily total?

Show the answer

Answer: 220 mg

Working: 110 mg x 2 doses = 220 mg a day.

Question 3

A fictional prescription reads dabigatran 150 mg twice a day using 150 mg capsules. How many capsules are needed for 28 days?

Show the answer

Answer: 56 capsules

Working: 1 capsule per dose x 2 doses = 2 capsules a day; 2 capsules x 28 days = 56 capsules.

eMC SmPC: Pradaxa 150 mg hard capsules

https://www.medicines.org.uk/emc/product/4703/smpc

Where marks are lost

  • Reporting the single dose instead of the daily total for a twice daily schedule.
  • Using the 150 mg twice daily total for a patient whose stated dose is 110 mg twice daily.
  • 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 anticoagulant doses depend on age, kidney function and interacting medicines, 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.

Practise until the method is automatic

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More calculation topics

See also the formula sheet, the eight sample questions and the approved calculator page.