Dose, Strength and Quantity
Convert a prescribed dose and available stock strength into the correct number of dose units.
How to prepare for the NMC Adult Nursing CBT
Combine reliable unit-aware calculation with newly qualified adult-nurse judgement grounded in the Code, current UK practice and the person in front of you.
Core concepts
Concept 1
Use required dose divided by stock dose, multiplied by the stock quantity, after aligning the units.
Exam cue: Write the required dose, available dose and available quantity before calculating.
Concept 2
The numerical answer must represent the quantity actually administered, not an intermediate conversion.
Exam cue: Check that the final unit answers the question asked.
Risk pitfalls and guardrails
Dividing stock strength by the prescribed dose.
Guardrail: Do not select a familiar task if it ignores deterioration, consent, medicines risk, scope, communication or follow-up.
Leaving mass units in the final field when a tablet count or volume is required.
Guardrail: Do not select a familiar task if it ignores deterioration, consent, medicines risk, scope, communication or follow-up.
Memory anchors
What is the core dose formula?
Required dose divided by stock dose, multiplied by stock quantity.
What must happen before using the formula?
Convert required and stock doses to the same unit.
What does stock quantity mean?
The number of tablets or volume that contains the stated stock dose.
What should the final unit describe?
The amount to administer, such as tablets, capsules or millilitres.
What is the final safety check?
Confirm the direction, unit and clinical plausibility of the answer.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
A prescription requires 750 mg of a medicine. Stock liquid contains 250 mg in 5 mL. What volume is required?
A patient is prescribed 400 mg. The available solution contains 200 mg in 5 mL. What volume should be measured?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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