Pharmacology and Medication Administration
Domain 8 covers drug action, safe administration, calculations and monitoring, drawing on the Kenya Essential Medicines List and standard formularies. Expect calculation items and toxicity recognition.
Rights and checks
Right patient, drug, dose, route, time, documentation, reason and response. Use two patient identifiers and read back every verbal order. A second checker is required for high-alert drugs: insulin, heparin, potassium, chemotherapy, opioids and blood products.
Calculations
- Dose required = prescribed dose per kg × weight.
- Volume to draw up = (dose required ÷ stock strength) × stock volume.
- Infusion rate in mL/h = total volume ÷ number of hours.
Monitoring and antidotes
- Digoxin therapeutic range roughly 0.5–2.0 ng/mL; toxicity causes nausea, xanthopsia (yellow-green vision), bradycardia and arrhythmia - withhold and report; hypokalaemia worsens toxicity.
- Paracetamol overdose: N-acetylcysteine. Warfarin: vitamin K. Heparin: protamine sulphate. Opioids: naloxone. Benzodiazepines: flumazenil.
- Magnesium sulphate: monitor respirations, reflexes and urine output; antidote calcium gluconate.
- Tuberculosis: rifampicin, isoniazid, pyrazinamide and ethambutol in the intensive phase, with pyridoxine to prevent isoniazid neuropathy.
Worked example
A 15 kg child is prescribed 15 mg/kg per dose. Stock is 250 mg in 5 mL. Reasoning: required dose = 15 × 15 = 225 mg. Volume = (225 ÷ 250) × 5 = 4.5 mL. Check that 225 mg is within the maximum single dose, confirm the route and frequency, and have a second nurse check the calculation.
Traps
Confusing milligrams and micrograms; treating "units" as interchangeable with mL; rounding a paediatric dose upward; giving lithium, digoxin or warfarin without checking interacting drugs and renal function.