Pharmacology Basics and Medication Safety
Overview
Pharmacology Basics and Medication Safety tests drug routes, simple pharmacokinetics, the rights of administration, and the checks that prevent medication errors.
Routes and pharmacokinetics
- Oral, sublingual, rectal, topical, inhalation, subcutaneous, intramuscular and intravenous.
- Absorption → distribution → metabolism (mainly liver) → excretion (mainly kidney).
- First-pass effect: oral drugs pass through the liver before reaching the circulation, so oral doses are often larger than intravenous.
- Intravenous acts fastest; subcutaneous absorption is slower than intramuscular.
The rights of medication
Right patient, right drug, right dose, right route, right time, right documentation - plus right reason and right to refuse. Check identity, allergy status and expiry; read the label three times; never prepare a drug without a label.
Worked example
The prescription is 500 mg and the stock is 250 mg tablets. Reasoning: 500 ÷ 250 = 2 tablets. Before giving, confirm the patient, check for allergy, read the label, give with water if appropriate, and document the dose, route and time immediately.
Traps that cost marks
- Crushing enteric-coated or sustained-release tablets.
- Guessing a dose when the prescription is unclear - clarify instead.
- Recording a medicine as given before it is actually administered.
- Forgetting that some drugs (for example, rifampicin) change urine colour - warn the patient rather than stopping the drug.