Common Registration Assessment, Part 1

Lidocaine 700 mg medicated plasters and daily limits for the GPhC assessment

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

Published 4 November 2026. Independent revision material, not GPhC questions, not for patient care.

A man holding his lower back outdoors
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 Versatis 700 mg medicated plaster states that the painful area should be covered with the plaster once daily for up to 12 hours within a 24-hour period.

The same information states that no more than three plasters should be used at the same time, and that each plaster-free interval must be at least 12 hours.

It also states that treatment should be re-evaluated after two to four weeks and stopped if there has been no response.

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

The method

  1. Identify the stated number of plasters used at one time and per day.
  2. Multiply the plaster count by 700 mg for the amount of lidocaine applied.
  3. Multiply the daily plaster count by the stated number of days for a supply quantity.
  4. Keep milligrams and plasters 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 patient applies the maximum of three Versatis plasters at the same time. Each plaster contains 700 mg of lidocaine. How many milligrams of lidocaine is applied at once?

Show the answer

Answer: 2,100 mg

Working: 3 plasters x 700 mg = 2,100 mg of lidocaine applied at one time.

Question 2

A fictional patient applies one plaster once daily for 14 days. How many plasters are used in total?

Show the answer

Answer: 14 plasters

Working: One plaster each day x 14 days = 14 plasters.

Question 3

A fictional patient uses two plasters each day. How many days does a pack of 30 plasters last?

Show the answer

Answer: 15 days

Working: 30 plasters / 2 plasters each day = 15 days.

eMC SmPC: Versatis 700 mg medicated plaster

https://www.medicines.org.uk/emc/product/290/smpc

Where marks are lost

  • Reporting 700 mg once when the question asks about two or three plasters.
  • Using more than three plasters at the same time in a calculation.
  • Letting the 12-hour wear and 12-hour plaster-free intervals double the stated daily plaster count.

Frequently asked questions

Are these official assessment questions?

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

Does each plaster deliver all 700 mg?

No. The plaster contains 700 mg of lidocaine. The exercises use that stated content for multiplication, not an absorbed dose.

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.

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More calculation topics

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