Pharmacy and Pharmacology
This domain tests drug classes, routes, storage, client safety, and the dose calculations technicians perform daily.
Core rules
- Dose in mg/kg multiplied by body weight in kg gives the dose in mg. Volume equals dose divided by concentration. Convert pounds to kilograms by dividing by 2.2.
- A 1% solution is 10 mg/mL; 5% is 50 mg/mL; 50% is 500 mg/mL. Read labels for mg/mL, not just percent.
- Know routes and limits: oral, IV, IM, SC, transdermal. Do not crush extended-release tablets unless directed. Flush IV catheters and check patency.
- Store drugs per label; protect light-sensitive drugs; keep vaccines and insulin refrigerated when required.
Worked example
A 12-kg dog is prescribed 5 mg/kg q12h of a 50 mg/mL liquid. Dose: 12 × 5 = 60 mg. Volume: 60 ÷ 50 = 1.2 mL per dose. If the owner asks for a teaspoon measure, convert: 1 tsp is about 5 mL, so a 1.2-mL dose is not a teaspoon; dispense an oral syringe. The reasoning checks units, concentration, and the client's measuring device, which are the three places errors occur.
Traps
Confusing mg and mcg, using pounds as kilograms, misplacing a decimal, treating 5% as 5 mg/mL, and assuming all tablets can be split all cost marks. Always recalculate a dose that looks unusual and confirm with the veterinarian.