Common Registration Assessment, Part 1
Rivaroxaban 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 20 October 2026. Independent revision material, not GPhC questions, not for patient care.
The BNF lists rivaroxaban tablets in four strengths: 2.5 mg, 10 mg, 15 mg and 20 mg.
The BNF gives the usual adult dose for atrial fibrillation as 20 mg once a day, and treatment of a deep-vein thrombosis or pulmonary embolism starts at 15 mg twice a day for 21 days, then moves to 20 mg once 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.
- Apply the stated frequency: once or twice each day.
- Scale to the stated duration only when a supply is requested.
- 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 rivaroxaban 20 mg once a day using 20 mg tablets. How many tablets are needed for 28 days?
Show the answer
Answer: 28 tablets
Working: 20 ÷ 20 = 1 tablet a day. 1 × 28 = 28 tablets.
Question 2
A fictional treatment course starts with rivaroxaban 15 mg twice a day for 21 days, using 15 mg tablets. How many tablets is the first phase?
Show the answer
Answer: 42 tablets
Working: 15 ÷ 15 = 1 tablet per dose. Twice a day is 2 tablets a day. 2 × 21 = 42 tablets.
Question 3
A fictional prescription specifies rivaroxaban 10 mg once a day for 2 weeks after a knee operation, using 10 mg tablets. How many tablets is the course?
Show the answer
Answer: 14 tablets
Working: 10 ÷ 10 = 1 tablet a day. 2 weeks is 2 × 7 = 14 days, so 1 × 14 = 14 tablets.
Exam approach
Regimen changes inside one question are deliberate. Mark where the starting phase ends and the maintenance phase begins before you multiply.
Where marks are lost
- Mixing up the four strengths when the strength is stated in the question.
- Carrying the twice-daily starting frequency into a once-daily phase.
- 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 doses?
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.