Common Registration Assessment, Part 1
Sertraline tablet strengths and dose steps 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 BNF lists sertraline tablets in five strengths: 25 mg, 50 mg, 100 mg, 150 mg and 200 mg.
The BNF gives the usual starting dose as 50 mg once a day, increased in steps of 50 mg at intervals of at least a week, up to a maximum of 200 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-daily frequency in view: one dose each day.
- Check any total against a stated maximum 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 sertraline 50 mg once a day using 25 mg tablets. How many tablets is one day, and how many for one week?
Show the answer
Answer: 2 tablets a day, 14 tablets a week
Working: 50 ÷ 25 = 2 tablets a day. 2 × 7 = 14 tablets.
Question 2
A fictional plan increases sertraline from 50 mg to 100 mg once a day, using 50 mg tablets. How many tablets are needed for 28 days at the new dose?
Show the answer
Answer: 56 tablets
Working: 100 ÷ 50 = 2 tablets a day. 2 × 28 = 56 tablets.
Question 3
A fictional plan uses the maximum dose of 200 mg once a day with 100 mg tablets. How many tablets are needed for a 30 day month?
Show the answer
Answer: 60 tablets
Working: 200 ÷ 100 = 2 tablets a day. 2 × 30 = 60 tablets.
Exam approach
A dose step changes only the prescribed mg; the method stays the same. Recalculate the single dose first, then scale.
Where marks are lost
- Treating the maximum 200 mg daily dose as the starting dose.
- Using the wrong tablet strength for the division.
- Reporting tablets per week when the question asks for 28 days or a month.
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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See also the formula sheet, the eight sample questions and the approved calculator page.