Pharmacology Basics and Drug Administration: Rights and Calculations
What this domain tests
Pharmacology Basics and Drug Administration tests drug routes, dosage calculation, the rights of administration, adverse effects and safe storage. Calculation questions are common.
Core rules
- The rights of medication: right patient, drug, dose, route, time, documentation, reason, response, and to refuse. Check allergies every time.
- Metric conversions: 1 g = 1,000 mg; 1 mg = 1,000 micrograms; 1 L = 1,000 mL.
- Tablets: dose required ÷ stock strength × stock volume. For liquids, use the same formula and check units.
- Insulin is measured in international units in an insulin syringe; never use a standard mL syringe for insulin.
- Do not crush enteric-coated or sustained-release tablets unless prescribed; give with the correct food relation.
- Report adverse drug reactions; store narcotics under double lock and keep a register.
Worked example
Order: 500 mg orally. Stock: 250 mg per 5 mL syrup. Reasoning: volume = (required dose ÷ stock strength) × stock volume = (500 ÷ 250) × 5 = 2 × 5 = 10 mL. Check that 10 mL is a reasonable volume for the child or adult, confirm the patient, drug and allergy status, measure with an oral syringe, and document the time and dose.
Traps
- Writing 0.5 mg as .5 mg; always use a leading zero.
- Mixing milligrams and micrograms.
- Measuring insulin in millilitres.
- Crushing enteric-coated tablets, which can cause gastric irritation.