Pharmacology Basics and Medication Administration
This domain tests drug basics plus the arithmetic and safety rules of giving medicines - a high-risk area where small errors matter.
Drug basics
Every drug has a chemical name, a generic (non-proprietary) name and one or more brand names; use the generic name in records and government facilities. Pharmacokinetics is what the body does to the drug - absorption, distribution, metabolism and excretion; pharmacodynamics is what the drug does to the body. Half-life determines dosing interval.
Routes and abbreviations
Oral, sublingual, rectal, topical, inhalation, subcutaneous, intramuscular and intravenous; intravenous acts fastest and avoids first-pass metabolism. Abbreviations: PO by mouth, SL sublingual, PR per rectum, SC subcutaneous, IM intramuscular, IV intravenous; OD once daily, BD twice daily, TDS three times daily, QID four times daily, HS at bedtime, AC before food, PC after food, SOS if required, STAT immediately.
The rights of administration
Right patient, right drug, right dose, right route, right time and right documentation, plus the patient's right to refuse.
Safety points
Check expiry and appearance, follow look-alike and sound-alike precautions, store insulin at 2–8 °C without freezing, check the vaccine vial monitor, and write decimals with a leading zero (0.5 mL, never .5). For anaphylaxis give adrenaline 0.5 mg intramuscularly (1:1000) into the mid-outer thigh.
Worked example
Order: 500 mg. Stock: 250 mg in 5 mL. Reasoning: 500 ÷ 250 = 2 doses, so 2 × 5 mL = 10 mL. Always state the unit and recheck the calculation before drawing up.
Traps that cost marks
Reading TDS as three doses spread across the day - it means every 8 hours. Confusing OD with BD. Forgetting that IV is the fastest route.