Pharmacology and Medication Management
Pharmacology questions test pharmacokinetics, safe administration, high-alert medicines, calculations and antidotes. The exam rewards applied calculations and safety checks.
Core rules and concepts
- Pharmacokinetics: absorption, distribution, metabolism, excretion. First-pass metabolism reduces oral bioavailability; half-life determines dosing interval and steady state, reached after about four to five half-lives.
- Narrow therapeutic index: digoxin, warfarin, lithium and aminoglycosides require serum monitoring.
- Rights of administration: right patient, drug, dose, route, time and documentation; add the right reason and right to refuse.
- High-alert medicines: insulin, heparin, opioids, potassium and chemotherapy need independent double-checking and clear labelling.
- Calculations: dose equals (desired ÷ available) × volume; weight-based doses in mg/kg; infusion rate in mL/h.
- Antidotes: opioid–naloxone, benzodiazepine–flumazenil, heparin–protamine, warfarin–vitamin K, paracetamol–N-acetylcysteine.
Worked example
A prescription reads 500 mg orally; stock is 250 mg in 5 mL. Desired 500 mg divided by available 250 mg equals 2; multiply by 5 mL to give 10 mL. Check that 10 mL contains 500 mg, confirm the patient’s identity and allergy status, and document immediately after administration.
Traps that cost marks
- Mixing milligrams and micrograms, especially with digoxin and adrenaline.
- Giving potassium by IV push-it must be diluted and infused.
- Rounding mid-calculation and producing an unsafe dose.
- Assuming flumazenil is routine in benzodiazepine overdose; it can precipitate seizures.