Common Registration Assessment, Part 1
Venlafaxine tablet 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 BNF lists standard venlafaxine tablets as 37.5 mg and 75 mg, and modified-release capsules as 37.5 mg, 75 mg and 150 mg.
The BNF gives a starting dose of 75 mg a day in 2 divided doses for standard tablets, and 75 mg once a day for modified-release, increased if needed up to a maximum that depends on the condition being treated.
Each question fixes the values needed for its arithmetic. Write the unit beside every step and keep the release form in view. All prescriptions and patients here are fictional; these are revision materials, not for patient care.
The method
- Identify the exact formulation, strength, dose and frequency supplied in the question.
- Divide a daily total into the stated number of doses for standard tablets.
- Calculate one dose first; divide prescribed mg by mg per tablet or capsule.
- Scale to the stated duration only when a supply is requested.
- 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 standard venlafaxine 75 mg a day in 2 divided doses using 37.5 mg tablets. How many tablets is one dose, and how many for 28 days?
Show the answer
Answer: 1 tablet per dose, 56 tablets for 28 days
Working: 75 ÷ 2 = 37.5 mg per dose. 37.5 ÷ 37.5 = 1 tablet per dose. 1 × 2 × 28 = 56 tablets.
Question 2
A fictional prescription specifies modified-release venlafaxine 150 mg once a day using 75 mg modified-release capsules. How many capsules is a 30 day month?
Show the answer
Answer: 60 capsules
Working: 150 ÷ 75 = 2 capsules a day. 2 × 30 = 60 capsules.
Question 3
A fictional plan increases modified-release venlafaxine to 225 mg once a day using 75 mg modified-release capsules. How many capsules is one week?
Show the answer
Answer: 21 capsules
Working: 225 ÷ 75 = 3 capsules a day. 3 × 7 = 21 capsules.
Exam approach
Confirm the release form first: standard tablets split the day into doses, modified-release is once a day. The arithmetic follows the form.
Where marks are lost
- Treating a divided daily dose as a once-daily dose.
- Mixing standard tablet strengths with modified-release capsule strengths.
- Reporting a daily total when the question asks for a single dose.
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.