Common Registration Assessment, Part 1

Memantine weekly titration steps and liquid pump doses for the GPhC assessment

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

Published 31 October 2026. Independent revision material, not GPhC questions, not for patient care.

Caregiver holding the hand of an elderly woman in a wheelchair
Photo from Pexels, used under the Pexels licence. It is a stock image and does not show the exercise.

The NHS lists memantine tablets as 5 mg, 10 mg, 15 mg and 20 mg, and a liquid (oral solution) containing 10 mg in 1 ml.

The NHS states that the starting dose is one 5 mg tablet once a day, usually increased by 5 mg every week until the dose is 20 mg, and that a starter pack contains 7 tablets of each strength.

The NHS states that the liquid starts at 0.5 ml once a day and is increased by 0.5 ml every week until the dose is 2 ml (20 mg), and that the pump gives 0.5 ml per press, so a dose uses 1 to 4 pumps.

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

The method

  1. Map each titration week to its stated dose before calculating.
  2. Convert milligrams to millilitres using the stated liquid strength of 10 mg in 1 ml.
  3. Convert millilitres to pump presses using 0.5 ml per press.
  4. Count tablets per pack or per week from the stated strengths.
  5. Check the final dose against the stated 20 mg target.

Three practice questions

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

Question 1

A fictional starter pack contains 7 tablets of each of the 5 mg, 10 mg, 15 mg and 20 mg strengths. How many tablets are in the pack?

Show the answer

Answer: 28 tablets

Working: 7 tablets x 4 strengths = 28 tablets.

Question 2

In week 3 of a fictional titration a patient takes 15 mg once a day using the liquid containing 10 mg in 1 ml. How many millilitres is each dose, and how many pump presses at 0.5 ml per press?

Show the answer

Answer: 1.5 ml; 3 presses

Working: 15 mg / 10 mg per ml = 1.5 ml; 1.5 ml / 0.5 ml per press = 3 presses.

Question 3

A fictional patient on the 20 mg daily target dose needs a 28-day supply of the liquid (10 mg in 1 ml). How many millilitres should be supplied?

Show the answer

Answer: 56 ml

Working: 20 mg / 10 mg per ml = 2 ml per day; 2 ml x 28 days = 56 ml.

NHS: How and when to take memantine

https://www.nhs.uk/medicines/memantine/how-and-when-to-take-memantine/

Where marks are lost

  • Increasing the dose by more than the stated 5 mg (or 0.5 ml) per week.
  • Confusing milligrams with millilitres or pump presses.
  • Treating arithmetic as evidence that a real prescription is clinically suitable.

Frequently asked questions

Are these official assessment questions?

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

Can a titration calculation justify changing a real titration schedule?

No. Follow the schedule in the exercise. Real dose changes need clinical checks.

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.