Common Registration Assessment, Part 1
Tamsulosin capsule strengths and daily doses for the GPhC assessment
Three original practice questions, with the working shown. Read the stated prescription or plan before calculating.
Published 19 October 2026. Independent revision material, not GPhC questions, not for patient care.
The NHS gives the usual dose of tamsulosin as 400 micrograms once a day, taken in the morning after breakfast or the first meal of the day.
The NHS also notes that a microgram is 1,000 times smaller than a milligram, so 400 micrograms is 0.4 mg.
Each question fixes the values needed for its arithmetic. Write the unit beside every step and keep micrograms and milligrams separate. All prescriptions and patients here are fictional; these are revision materials, not for patient care.
The method
- Identify the exact strength, dose and frequency supplied in the question, with its unit.
- Convert micrograms to milligrams by dividing by 1,000 only when the question asks for mg.
- Calculate one dose first; divide the prescribed amount by the stated strength.
- Scale to the stated duration only when a supply is requested.
- Check the unit of the final answer before reporting it.
Three practice questions
Work each one on paper first, then open the answer. All patients and prescriptions are fictional.
Question 1
A fictional prescription specifies tamsulosin 400 micrograms once a day using 400 microgram capsules. How many capsules are needed for 28 days?
Show the answer
Answer: 28 capsules
Working: 400 ÷ 400 = 1 capsule a day. 1 × 28 = 28 capsules.
Question 2
A fictional prescription specifies tamsulosin 400 micrograms once a day. What is the daily dose in milligrams, and what is the total in milligrams over 30 days?
Show the answer
Answer: 0.4 mg a day, 12 mg over 30 days
Working: 400 ÷ 1,000 = 0.4 mg a day. 0.4 × 30 = 12 mg.
Question 3
A fictional prescription specifies tamsulosin 400 micrograms once a day using 400 microgram modified-release tablets for 8 weeks. How many tablets is the course?
Show the answer
Answer: 56 tablets
Working: 8 weeks is 8 × 7 = 56 days. 400 ÷ 400 = 1 tablet a day, so 1 × 56 = 56 tablets.
Exam approach
Unit errors outrank arithmetic errors here. Circle the unit in the question, convert deliberately, and write the unit next to the answer.
Where marks are lost
- Writing 400 mg instead of 400 micrograms: a 1,000-fold error.
- Multiplying by 1,000 instead of dividing when converting micrograms to mg.
- Forgetting to convert weeks to days before multiplying.
Frequently asked questions
Are these official assessment questions?
No. They are original revision exercises, not official GPhC questions and not for patient care.
Do I need to memorise the strengths?
The exercise supplies them. In the assessment, read any given product information exactly as written.
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
Try 15 free questions with worked answers. No sign-up required.
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