Topic module

Dose, Strength and Quantity

Convert a prescribed dose and available stock strength into the correct number of dose units.

Long-form learning
Concept to Risk to Memory to Check-up

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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

1-2 question checkpoint

A prescription requires 750 mg. The available tablets contain 250 mg each. How many tablets are required for one dose?

A prescribed dose is 1.2 g. An oral liquid contains 400 mg in 5 mL. What volume contains the prescribed dose?

Answer all questions to submit.

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