Common Registration Assessment, Part 1
Azithromycin tablet strengths and short courses 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.
The BNF lists azithromycin tablets in two strengths: 250 mg and 500 mg.
The BNF gives the usual adult dose for respiratory, ear, skin and soft-tissue infections as 500 mg once a day for 3 days, or 500 mg on day 1 followed by 250 mg once a day for 4 days.
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
- Identify the exact strength, dose and frequency supplied in the question.
- Calculate one dose first; divide prescribed mg by mg per tablet.
- Watch for a day-by-day change in dose across the course.
- Scale to the stated course length only when a supply is requested.
- Check the tablet 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 azithromycin 500 mg once a day for 3 days using 500 mg tablets. How many tablets is the course?
Show the answer
Answer: 3 tablets
Working: 500 ÷ 500 = 1 tablet a day. 1 × 3 = 3 tablets.
Question 2
A fictional prescription specifies azithromycin 500 mg on day 1, then 250 mg once a day for 4 days, all using 250 mg tablets. How many tablets is the course?
Show the answer
Answer: 6 tablets
Working: Day 1: 500 ÷ 250 = 2 tablets. Days 2 to 5: 250 ÷ 250 = 1 tablet a day, so 4 tablets. 2 + 4 = 6 tablets.
Question 3
A fictional prescription specifies azithromycin 500 mg once a day for 3 days using 250 mg tablets. How many tablets is the course?
Show the answer
Answer: 6 tablets
Working: 500 ÷ 250 = 2 tablets a day. 2 × 3 = 6 tablets.
Exam approach
Step-down courses are really two sums: work day 1 on its own, then the remaining days, and add them before answering.
Where marks are lost
- Missing that the dose changes after day 1 in a step-down course.
- Mixing up the 250 mg and 500 mg strengths when the strength is stated in the question.
- Extending the course beyond the stated number of days.
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 course lengths?
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.
Practise until the method is automatic
Try 15 free questions with worked answers. No sign-up required.
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See also the formula sheet, the eight sample questions and the approved calculator page.