Common Registration Assessment, Part 1
Fluoxetine capsule strengths and liquid doses for the GPhC assessment
Three original practice questions, with the working shown. Read the stated prescription or plan before calculating.
Published 18 October 2026. Independent revision material, not GPhC questions, not for patient care.
The BNF lists fluoxetine capsules in three strengths: 10 mg, 20 mg and 60 mg. The oral solution contains 20 mg in each 5 mL.
The NHS gives the usual adult dose as 20 mg a day, increased gradually if needed up to a maximum of 60 mg a day. For children the usual dose is 10 mg a day, which may be increased to 20 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 daily total. 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.
- Convert a 20 mg/5 mL liquid strength to mg per mL if a dose-to-volume conversion is needed.
- Calculate one dose first; for capsules divide prescribed mg by mg per capsule.
- Scale to the stated frequency and duration only when a daily total or 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 fluoxetine 40 mg once a day using 20 mg capsules. How many capsules is one day, and how many for 28 days?
Show the answer
Answer: 2 capsules a day, 56 capsules for 28 days
Working: 40 ÷ 20 = 2 capsules a day. 2 × 28 = 56 capsules.
Question 2
A fictional prescription for a child specifies fluoxetine 10 mg once a day using the oral solution that contains 20 mg in 5 mL. What volume is one dose?
Show the answer
Answer: 2.5 mL
Working: 20 mg in 5 mL is 4 mg per mL. 10 ÷ 4 = 2.5 mL.
Question 3
A fictional plan increases an adult to the maximum dose of 60 mg once a day using 20 mg capsules. How many capsules is one week?
Show the answer
Answer: 21 capsules
Working: 60 ÷ 20 = 3 capsules a day. 3 × 7 = 21 capsules.
Exam approach
Keep capsule strengths and the liquid strength separate. A daily total is just one dose multiplied by the stated frequency, so get the single dose right first.
Where marks are lost
- Treating the maximum 60 mg daily dose as the usual starting dose.
- Using 20 mg per mL instead of 4 mg per mL for the oral solution.
- 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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- Amlodipine tablet and liquid strengths for the GPhC assessment
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- Citalopram drops and tablet equivalents for the GPhC assessment
- Fexofenadine tablet strengths by age for the GPhC assessment
- Gliclazide standard and slow-release tablets for the GPhC assessment
- Lansoprazole capsule strengths and course lengths for the GPhC assessment
- Naproxen tablet strengths and daily maximums for the GPhC assessment
- Propranolol tablet strengths and daily doses for the GPhC assessment
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- Losartan tablet strengths and daily doses for the GPhC assessment
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- Montelukast tablets, chewables and granules by age for the GPhC assessment
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See also the formula sheet, the eight sample questions and the approved calculator page.