Common Registration Assessment, Part 1

Tapentadol 50 mg tablets and daily dose limits for the GPhC assessment

Three original practice questions, with the working shown. Read the stated prescription or plan before calculating.

Published 11 November 2026. Independent revision material, not GPhC questions, not for patient care.

A person sitting on a bed hugging their knees in a dim red-lit room
Photo from Pexels, used under the Pexels licence. It is a stock image and does not show the exercise.

The manufacturer's UK product information for Palexia 50 mg film-coated tablets states that patients should start treatment with single doses of 50 mg every 4 to 6 hours, that on the first day an additional dose may be taken as soon as one hour after the initial dose if pain control is not achieved, and that the dose is then titrated individually.

The same information states that total daily doses greater than 700 mg on the first day of treatment and maintenance daily doses greater than 600 mg have not been studied and are therefore not recommended.

For moderate hepatic impairment, it states that treatment should be initiated at the lowest available strength (50 mg), not administered more frequently than once every 8 hours, and that at initiation a daily dose greater than 150 mg is not recommended.

Each question fixes the values needed for its arithmetic. Write the unit beside every step and distinguish a single dose from a daily total. All prescriptions and patients here are fictional; these are revision materials, not for patient care.

The method

  1. Read the stated dose per administration and the stated interval.
  2. Divide 24 hours by the stated interval for the daily dose count, then multiply by the tablet strength.
  3. Check the daily total against the stated 600 mg maintenance limit (700 mg on day 1).
  4. Keep mg per dose, mg per day, tablets and hours separate; convert only when the question asks.

Three practice questions

Work each one on paper first, then open the answer. All patients and prescriptions are fictional.

Question 1

A fictional adult takes tapentadol 50 mg every 6 hours at a steady schedule. How many doses and how many mg are taken in 24 hours?

Show the answer

Answer: 4 doses; 200 mg

Working: 24 hours / 6 hours = 4 doses. 4 x 50 mg = 200 mg per day.

Question 2

A fictional adult is titrated to tapentadol 150 mg per dose every 6 hours. What is the daily total, and is it within the label's studied maintenance limit?

Show the answer

Answer: 600 mg daily; within the limit, as maintenance daily doses greater than 600 mg are not recommended

Working: 24 hours / 6 hours = 4 doses. 4 x 150 mg = 600 mg per day. The label states maintenance daily doses greater than 600 mg have not been studied and are not recommended, so 600 mg is the ceiling.

Question 3

A fictional patient with moderate hepatic impairment starts tapentadol at the label limits for that group. What is the longest dosing frequency allowed, the maximum number of doses in 24 hours, and the stated day-1 daily maximum?

Show the answer

Answer: No more frequent than once every 8 hours; 3 doses; 150 mg

Working: 24 hours / 8 hours = 3 doses at most. 3 x 50 mg = 150 mg, matching the label's stated 150 mg day-1 maximum for this group.

eMC SmPC: Palexia 50 mg film-coated tablets

https://www.medicines.org.uk/emc/product/5159/smpc

Where marks are lost

  • Applying the day-1 limit to a maintenance day; 700 mg applies to the first day only, maintenance stays at or below 600 mg.
  • Reading 'every 4 to 6 hours' as a fixed interval; the daily total depends on the interval stated in the question.
  • Forgetting the hepatic limits; in moderate hepatic impairment the label caps initiation at 50 mg no more often than every 8 hours, 150 mg on day 1.

Frequently asked questions

Are these official assessment questions?

No. They are original revision exercises, not official GPhC questions and not for patient care.

Does this calculation decide a real tapentadol dose?

No. Follow the stated prescription in the exercise. Real dosing follows the prescriber and the product information.

How should I check the answer?

Divide 24 hours by the stated interval for the daily dose count, multiply by the strength, then compare with the stated 600 mg maintenance limit.

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.

Try 15 free questionsSee pricing

More calculation topics

See also the formula sheet, the eight sample questions and the approved calculator page.