Pharmacology and Medication Safety
Domain 8 - Pharmacology and Medication Safety
This domain tests safe prescribing support: the rights of administration, accurate calculation, high-alert medication handling, adverse reaction reporting, antimicrobial stewardship and error management. Most questions are calculations or 'what should the nurse do next' scenarios.
Core rules
- Rights of administration: right patient (two identifiers), right drug, right dose, right route, right time, right reason, right documentation, right to refuse, and right response. Add right to know and right form.
- Check the prescription for legibility, completeness and legality before administration. An unclear order must be clarified with the prescriber, never guessed.
- Calculation: dose required ÷ stock strength × stock volume. Convert units before you divide, and never write a trailing zero (write 0.5 mg, not .5 mg).
- High-alert medications include insulin, heparin, opioids, potassium chloride, chemotherapy and concentrated electrolytes. They require independent double checks, standard concentrations, pumps and clear labelling.
- Look-alike, sound-alike names and unfamiliar paediatric doses are error traps; question any dose outside the usual range.
- Antibiotic stewardship: right drug, dose, route and duration; take cultures before the first dose; review at 48–72 hours.
- Report all adverse drug reactions and errors through the national pharmacovigilance and incident systems - reporting is for learning, not punishment.
Worked example
A 70 kg adult is prescribed dopamine 5 mcg/kg/min. The bag contains 400 mg in 250 mL. Reasoning: first convert the concentration - 400 mg = 400,000 mcg in 250 mL, so 1600 mcg/mL. Dose needed per minute: 5 × 70 = 350 mcg/min. Per hour: 350 × 60 = 21,000 mcg/hour. Rate: 21,000 ÷ 1600 = 13.1 mL/hour. Then set the pump, double check the concentration with a second nurse, label the line, monitor pulse and blood pressure, and watch the infusion site for extravasation.
Traps
- Mixing milligrams and micrograms.
- Rounding a paediatric dose up 'to make it easier to measure'.
- Giving a drug because the order is written, without checking allergies or the last dose.
- Drawing up long-acting insulin before clear soluble insulin in the same syringe.
- Failing to report a near-miss because no harm occurred.