Pharmacology and Medication Management
Pharmacology items are calculation-heavy and safety-heavy. The exam expects exact arithmetic, correct unit conversion and recognition of high-alert drugs. Most stems ask what you do before administering, or what you suspect when a patient on a familiar drug develops a new symptom.
The rights and checks
- Right patient, right drug, right dose, right route, right time, right documentation; add right reason and right to refuse.
- Check the prescription for legibility, allergy status, interactions and expiry. Two nurses check and record controlled drugs.
- Never crush modified-release or enteric-coated tablets. For nasogastric administration, use liquid or dispersible forms, give each drug separately, flush between drugs, and separate from feeds as advised.
High-alert drugs
- Potassium chloride concentrate is never given as an intravenous push; it must be diluted and infused at a controlled rate.
- Insulin must be measured in an insulin syringe and checked against the prescribed type and timing. Treat hypoglycaemia with fast-acting oral carbohydrate if the patient can swallow, or intravenous glucose if not, then recheck.
- Warfarin is monitored by INR with a usual target of 2 to 3. Vitamin K is the antidote for major bleeding or over-anticoagulation.
- Heparin is monitored by aPTT; protamine sulfate is the antidote. A platelet count falling by more than 50 percent suggests heparin-induced thrombocytopenia, which paradoxically causes thrombosis.
- Digoxin toxicity causes nausea, visual disturbance such as yellow-green halos, confusion and bradyarrhythmia. Hypokalaemia increases risk; digoxin-specific antibody is the antidote.
Worked example
A child weighing 15 kg is prescribed amoxicillin 25 mg per kg per dose. Stock suspension is 125 mg in 5 mL. What volume do you give? Reasoning: the required dose is 15 multiplied by 25, which equals 375 mg. The concentration is 125 mg per 5 mL, so 1 mL contains 25 mg. Therefore 375 divided by 25 equals 15 mL. Cross-check against the maximum single dose for the child's age and confirm the frequency before administration. Writing 3 mL would be a tenfold-type error and potentially subtherapeutic.
Traps that cost marks
- Misplacing a decimal point or mixing milligrams with micrograms.
- Assuming a pro re nata order can be given as often as requested without checking the maximum dose and interval.
- Reporting adverse drug reactions to nobody; report to the Drug Office of the Department of Health.