Common Registration Assessment, Part 1

Moxonidine titration steps and daily dose maximums for the GPhC assessment

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

Published 14 November 2026. Independent revision material, not GPhC questions, not for patient care.

An arrangement of plain medicine bottles, capsules and blister packs on a flat surface
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 Physiotens (moxonidine) starts treatment at 200 micrograms in the morning. After 3 weeks the dose may be titrated to 400 micrograms, given as one dose or as divided doses morning and evening.

If the response is still unsatisfactory after a further 3 weeks, the dose may rise to a maximum of 600 micrograms daily in 2 divided doses, and no single dose should exceed 400 micrograms.

In moderate renal dysfunction, a GFR above 30 but below 60 ml/min, a single dose must not exceed 200 micrograms and the daily dose 400 micrograms. Severe renal dysfunction, a GFR below 30 ml/min, is a contraindication.

Each question fixes the values needed for its arithmetic. Keep micrograms as the unit throughout and state the weeks at each step. All prescriptions and patients here are fictional; these are revision materials, not for patient care.

The method

  1. Start with 200 micrograms in the morning.
  2. After 3 weeks, titrate to 400 micrograms as one dose or divided morning and evening.
  3. After a further 3 weeks, the daily maximum is 600 micrograms in 2 divided doses.
  4. Keep every single dose at or below 400 micrograms.
  5. With a GFR of 30 to 60 ml/min, cap a single dose at 200 micrograms and the day at 400 micrograms; below 30 ml/min moxonidine is contraindicated.

Three practice questions

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

Question 1

A fictional patient starts at 200 micrograms each morning, then titrates to 400 micrograms after 3 weeks, divided morning and evening. How many 200 microgram tablets a day is the titrated dose?

Show the answer

Answer: 2 tablets a day, one in the morning and one in the evening

Working: 400 / 200 = 2 tablets a day. Divided morning and evening, that is one 200 microgram tablet twice a day.

Question 2

A fictional patient reaches the maximum of 600 micrograms daily in 2 divided doses. How is it built from 200 microgram tablets, and does any single dose break the limit?

Show the answer

Answer: 400 micrograms in one dose and 200 micrograms in the other; the 400 microgram dose sits at the single-dose maximum, not above it

Working: 600 = 400 + 200, so two 200 microgram tablets in one dose and one in the other. The product information caps a single dose at 400 micrograms, so the larger dose is at the limit.

Question 3

A fictional patient has a GFR of 45 ml/min. What limits apply to moxonidine dosing?

Show the answer

Answer: A single dose of no more than 200 micrograms and no more than 400 micrograms a day

Working: A GFR of 45 ml/min is above 30 but below 60 ml/min, the moderate renal dysfunction band in the product information, so the single-dose and daily caps are 200 and 400 micrograms.

eMC SmPC: Physiotens 200 microgram Tablets

https://www.medicines.org.uk/emc/product/1170/smpc

Where marks are lost

  • Titrating before 3 weeks on the current dose.
  • Giving 600 micrograms as a single dose instead of 2 divided doses, breaking the 400 microgram single-dose limit.
  • Applying the standard titration when the GFR is between 30 and 60 ml/min, where the caps are lower.

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 dose?

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

How should I check the answer?

Check the weeks at each step, keep every single dose at or below 400 micrograms, and apply the renal caps when the GFR is below 60 ml/min.

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.