Common Registration Assessment, Part 1

Fluconazole capsule strengths and single doses for the GPhC assessment

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

Published 21 October 2026. Independent revision material, not GPhC questions, not for patient care.

Mixed pills in pill organizer
Photo from Pexels, used under the Pexels licence. It is a stock image and does not show the exercise.

The NHS lists fluconazole capsules in three strengths: 50 mg, 150 mg and 200 mg.

The BNF gives the usual adult dose for vaginal thrush as a single 150 mg dose, and for thrush that keeps coming back as 150 mg every 72 hours for 3 doses, then 150 mg once a week for 6 months.

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

The method

  1. Identify the exact strength, dose and frequency supplied in the question.
  2. Calculate one dose first; divide prescribed mg by mg per capsule.
  3. Watch for single doses and doses spaced 72 hours apart.
  4. Scale to the stated duration only when a supply is requested.
  5. Check the capsule count is a whole number before reporting it.

Three practice questions

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

Question 1

A fictional prescription specifies fluconazole 150 mg as a single dose using 150 mg capsules. How many capsules are needed?

Show the answer

Answer: 1 capsule

Working: 150 ÷ 150 = 1 capsule, taken once.

Question 2

A fictional plan specifies fluconazole 150 mg every 72 hours for 3 doses using 150 mg capsules. How many capsules is the course?

Show the answer

Answer: 3 capsules

Working: 150 ÷ 150 = 1 capsule per dose. 3 doses is 1 × 3 = 3 capsules.

Question 3

A fictional prescription specifies fluconazole 50 mg once a day for 14 days using 50 mg capsules. How many capsules is the course?

Show the answer

Answer: 14 capsules

Working: 50 ÷ 50 = 1 capsule a day. 1 × 14 = 14 capsules.

Exam approach

Interval dosing is the trap here. Turn 72 hours into three days before counting doses across a week.

Where marks are lost

  • Repeating a single dose when the question says it is taken once.
  • Treating a 72-hour interval as a daily dose.
  • Mixing up the 50 mg, 150 mg and 200 mg strengths when the strength is stated in the question.

Frequently asked questions

Are these official assessment questions?

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

Do I need to memorise the strengths?

The exercise supplies them. In the assessment, read any given product information exactly as written.

How should I check the answer?

Check the requested unit, then work backwards from the quantity to the stated dose and course.

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.