Common Registration Assessment, Part 1

Clobazam 10 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 blister pack of white and pink tablets on a pink background
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 Clobazam 10 mg Tablets states that the usual anxiolytic dose for adults is 20 to 30 mg daily in divided doses or as a single dose given at night, that doses up to 60 mg daily have been used in adult in-patients with severe anxiety, and that the lowest dose that can control symptoms should be used.

The same information states that for anxiety the treatment should not be used for longer than 4 weeks, that treatment should always be withdrawn gradually, and that in the elderly doses of 10 to 20 mg daily in anxiety may be used.

Clobazam also comes as an oral suspension, with the 10 mg/5 ml strength suited to higher doses and the 5 mg/5 ml strength suited to lower doses, so a dose can be expressed in tablets or in ml.

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

The method

  1. Read the stated daily dose and whether it is single or divided.
  2. Divide the stated mg by 10 for the 10 mg tablet count, or convert to ml at 2 mg per ml for the 10 mg/5 ml suspension.
  3. Check the dose against the stated 20 to 30 mg usual range and the patient group.
  4. Keep mg, tablets, ml and dose limits 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 clobazam 20 mg as a single dose at night for anxiety, using 10 mg tablets. How many tablets is that each night, and is the dose within the label's usual adult range?

Show the answer

Answer: 2 tablets; yes, 20 mg is the bottom of the 20 to 30 mg usual range

Working: 20 / 10 = 2 tablets. The label's usual anxiolytic dose for adults is 20 to 30 mg daily, taken as a single dose at night or divided.

Question 2

A fictional adult takes clobazam 30 mg daily in divided doses for anxiety, using the 10 mg/5 ml oral suspension. How many ml per day is that, and how many ml per dose if split into two equal doses?

Show the answer

Answer: 15 ml per day; 7.5 ml per dose

Working: At 10 mg per 5 ml (2 mg per ml), 30 mg = 15 ml daily. 15 / 2 = 7.5 ml per dose.

Question 3

A fictional elderly patient takes clobazam 10 mg daily for anxiety, using 10 mg tablets. How many tablets is that each day, and which label range does it sit in?

Show the answer

Answer: 1 tablet; the 10 to 20 mg elderly range

Working: 10 / 10 = 1 tablet. The label states doses of 10 to 20 mg daily in anxiety may be used in the elderly, below the usual adult 20 to 30 mg range.

eMC SmPC: Clobazam 10 mg Tablets

https://www.medicines.org.uk/emc/product/15103/smpc

Where marks are lost

  • Counting one tablet per dose regardless of the dose; the 10 mg tablet covers 10 mg, so 20 mg needs two tablets.
  • Converting with the wrong suspension strength; 10 mg/5 ml is 2 mg per ml, while 5 mg/5 ml is 1 mg per ml.
  • Passing the usual range without a stated reason; the usual adult anxiolytic dose is 20 to 30 mg daily, with up to 60 mg only for in-patients with severe anxiety.

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 clobazam 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 the stated mg by 10 for tablets, or convert at 2 mg per ml for the 10 mg/5 ml suspension, then check against the stated range.

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.