Common Registration Assessment, Part 1
Salbutamol inhaler puffs and daily maximums for the GPhC assessment
Three original practice questions, with the working shown. Read the stated prescription or plan before calculating.
Published 18 October 2026. Independent revision material, not GPhC questions, not for patient care.
The NHS advises 1 or 2 puffs when needed, up to a maximum of 4 times in 24 hours. In a sudden asthma attack up to 10 puffs can be used, waiting 30 to 60 seconds between puffs.
The BNF lists the common pressurised inhaler at 100 micrograms per puff, and the NHS notes that some inhalers contain a fixed number of 200 doses.
Each question fixes the values needed for its arithmetic. Write the unit beside every step and keep puffs, micrograms and days as separate units. All patients here are fictional; these are revision materials, not for patient care.
The method
- Identify the puffs per use and the number of uses supplied in the question.
- Multiply puffs by 100 micrograms if a microgram total is requested.
- Divide the 200-dose canister total by puffs per day for a duration.
- Keep the 4-times-in-24-hours maximum separate from attack dosing.
- Check the final unit matches what the question asked.
Three practice questions
Work each one on paper first, then open the answer. All patients and prescriptions are fictional.
Question 1
A fictional patient uses 2 puffs at a time, the maximum of 4 times in 24 hours. At 100 micrograms per puff, how many micrograms is that in 24 hours?
Show the answer
Answer: 800 micrograms
Working: 2 puffs × 4 times = 8 puffs. 8 × 100 = 800 micrograms.
Question 2
A fictional patient uses 2 puffs twice a day, every day. How many days will a 200-dose inhaler last?
Show the answer
Answer: 50 days
Working: 2 puffs × 2 times = 4 puffs a day. 200 ÷ 4 = 50 days.
Question 3
A fictional patient uses 1 puff once a day. How many days will a 200-dose inhaler last?
Show the answer
Answer: 200 days
Working: 1 puff a day. 200 ÷ 1 = 200 days.
Exam approach
Inhaler arithmetic is a units exercise: puffs per day for duration, micrograms per puff for dose. Write the unit beside each number and the final division or multiplication picks itself.
Where marks are lost
- Treating the 10-puff attack guidance as the everyday maximum.
- Multiplying micrograms by days when the question asks for a single 24-hour period.
- Rounding a canister duration up instead of reporting whole days of full use.
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 micrograms per puff?
The exercise supplies it. 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 puffs and strength.
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.