Common Registration Assessment, Part 1
Nortriptyline tablet strengths and nightly doses for the GPhC assessment
Three original practice questions, with the working shown. Read the stated prescription or plan before calculating.
Published 23 October 2026. Independent revision material, not GPhC questions, not for patient care.
The BNF lists nortriptyline tablets in three strengths: 10 mg, 25 mg and 50 mg.
The BNF gives the usual adult start for nerve pain as 10 mg once a day taken at night, increased gradually if needed up to 75 mg a day.
Each question fixes the values needed for its arithmetic. Write the unit beside every step and keep a single dose separate from a supply total. 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.
- Calculate one dose first; divide prescribed mg by mg per tablet.
- Scale to the stated duration only when a supply is requested.
- Keep the once-nightly frequency in view: one dose each day.
- Check the tablet count is a whole number 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 nortriptyline 10 mg once a day at night using 10 mg tablets. How many tablets are needed for 28 days?
Show the answer
Answer: 28 tablets
Working: 10 ÷ 10 = 1 tablet a day. 1 × 28 = 28 tablets.
Question 2
A fictional plan increases nortriptyline to 25 mg once a day at night using 25 mg tablets. How many tablets are needed for 30 days?
Show the answer
Answer: 30 tablets
Working: 25 ÷ 25 = 1 tablet a day. 1 × 30 = 30 tablets.
Question 3
A fictional plan maintains nortriptyline at 75 mg once a day at night using 25 mg tablets for 14 days. How many tablets is the supply?
Show the answer
Answer: 42 tablets
Working: 75 ÷ 25 = 3 tablets a day. 3 × 14 = 42 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
- Mixing up the three strengths when the strength is stated in the question.
- Reporting a daily total when the question asks for a supply, or the other way round.
- Forgetting that the nightly dose may use several tablets of a lower strength.
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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