Common Registration Assessment, Part 1
Quantities for titration packs
Three original questions on titration schedules, with the working shown and the usual traps pointed out.
Published 4 October 2026. Independent revision material, not GPhC questions, not for patient care.
A titration schedule raises the dose week by week. The quantity question is how many tablets of each strength cover the whole course, and the arithmetic is a running total, not a single multiplication.
Break the schedule into its weekly blocks, calculate the milligrams or tablets for each block, then add.
The method
- Write out the dose for each week of the schedule.
- Multiply each weekly dose by 7 for that week's total.
- Choose the strengths that make each weekly dose and count tablets per week.
- Add the weeks for the full course quantity.
- For stopped treatment, count tablets actually used and subtract from the supply.
Three practice questions
Work each one on paper first, then open the answer. All drugs and patients are fictional.
Question 1
Drug X is titrated over 28 days: 5 mg once daily in week 1, 10 mg once daily in week 2, and 15 mg once daily in weeks 3 and 4. Using 5 mg and 10 mg tablets with the fewest tablets per dose, how many of each strength are supplied?
Show the answer
Answer: 21 of the 5 mg tablets and 21 of the 10 mg tablets
Working: Week 1: 7 × 5 mg. Week 2: 7 × 10 mg. Weeks 3-4: 14 × (10 + 5). Totals: 5 mg = 7 + 14 = 21; 10 mg = 7 + 14 = 21.
Question 2
Drug Y is titrated as 25 mg daily in week 1, 50 mg daily in week 2 and 75 mg daily in weeks 3 and 4. Only 25 mg tablets are available. How many tablets cover the 28 day course?
Show the answer
Answer: 63 tablets
Working: Week 1: 7 × 1 = 7. Week 2: 7 × 2 = 14. Weeks 3-4: 14 × 3 = 42. Total = 7 + 14 + 42 = 63 tablets.
Question 3
A 14 day starter pack of Drug Z contains enough 5 mg tablets for 1 tablet daily in week 1 and 2 tablets daily in week 2. The patient stops at the end of day 10. How many tablets are left?
Show the answer
Answer: 8 tablets
Working: Pack holds 7 + 14 = 21 tablets. Used: 7 in week 1 plus 3 × 2 = 6 in week 2, so 13 used. 21 - 13 = 8 left.
How this is examined
Titration questions test patience more than maths. Write the weeks as a small table and total it; mental running totals are where the marks go.
Where marks are lost
- Multiplying the final dose by 28 instead of totalling each week.
- Counting weeks 3 and 4 as one week: 14 doses, not 7.
- For stopped-treatment questions, subtracting days instead of tablets used.
Frequently asked questions
Do titration packs always use the fewest tablets?
No. Many manufacturers supply one strength throughout for simplicity. Answer from the strengths the stem gives you, and minimise only if asked.
What if a dose is increased mid-week?
Count the exact days at each dose. The stem will give you the switch day; multiply each dose by its own number of days.
Sources
- BNF, guidance on prescribing
- GPhC, Common Registration Assessment specification and permitted items for 2026
The questions above are original and use fictional drugs. 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.
More calculation topics
- Dose by weight calculations for the GPhC assessment
- Volume to give: liquid medicine calculations
- Percentage strength calculations: w/v, w/w and ratios
- Dilution calculations with C1V1 = C2V2
- Infusion rate calculations in mL per hour
- Drip rate calculations: drops per minute
- Body surface area calculations
- Creatinine clearance (Cockcroft-Gault) calculations
- Moles and millimoles calculations
- Displacement volume calculations for reconstitution
- Quantity to supply calculations
- Using a provided formula in calculations
- Dose information from packaging and labels
- Diluting a stock to a lower strength
- Medicine cost and switch calculations
- Rounding rules in calculations
- Enteral feed rate calculations
- Electrolyte content over time
- Infusion dose per kg per hour
- Rounding doses to measurable volumes
- Relative risk and relative risk reduction
- Absolute risk reduction and number needed to treat
- Odds ratio and confidence intervals
- Relative versus absolute risk reduction
- Loading dose and volume of distribution
- Top-up doses from measured drug levels
- Salt correction factors
- Mass and molar drug concentrations
- Half-life and falling drug levels
- Steady-state concentration and infusion rate
- Bioavailability and equivalent oral doses
- Oral maintenance dose and dosing interval
- Elimination rate constant and half-life
- Accumulation towards steady state
- Ratio strengths and one in X
- Serial dilution factors
- Mixing solutions of different strengths
- Tablet quantities for reducing regimens
- Equivalent doses from provided conversion tables
- Thresholds and dose-banding algorithms
- Unit conversions for mass and volume
- Units and units per mL
- Reconstituting powders and final concentration
- Millimoles and milliequivalents
- Infusion time and volume remaining
- Days supply from pack sizes
- Percentage w/v and w/w conversions
- Ideal and adjusted body weight from formulae
- Diluting creams and ointments by weight
- Scaling a formula to a batch size
- Age-band doses from a provided table
- Tablet fractions and split doses
- Stones, pounds, inches and metric conversions
- Micrograms per minute from mg per hour
- Percentage change and mark-up
- Molar solutions and mass per volume
- Osmolarity from component concentrations
- Direct proportion and cross-multiplication
- Scientific notation and very small quantities
- Stock use and reorder quantities
- Parts per million and very dilute solutions
- Sodium chloride equivalents and isotonic solutions
- Density and specific gravity conversions
- Doses per day and hours between doses
- Finding the volume of diluent to add
- Capping a dose at a stated maximum
- Whole vials and ampoules to draw up
- Reading values from a provided graph
- Micrograms per kg per minute infusions
- Percentage composition of a compound preparation
- Suppository displacement values
- Isotonicity by freezing point depression
- Energy content of parenteral nutrition
- Syringe driver rate calculations
- Area under the curve calculations
- Renal dose adjustments using provided bands
- Insulin units and infusion calculations
- Working backwards from a stated dose
- Doses and days from multi-dose devices
- Combined additives in one infusion
- BMI calculations for the GPhC assessment
- Fewest tablets to make a dose
- Clearance from half-life and volume of distribution
- Maintenance fluid requirements by weight
- Sodium load from effervescent tablets
- Ethanol content of liquid preparations
- Oxygen cylinder duration calculations
- Urine output and fluid balance calculations
- Infusion line priming and dead space
See also the formula sheet, the eight sample questions and the approved calculator page.