Pharmacy and Pharmacology
What this domain tests
Pharmacy and Pharmacology asks whether you can turn a written prescription into a safe, accurate dose and then handle the drug correctly in the hospital. Expect dose calculations, unit conversions, drug classes and routes, interactions, controlled-substance rules, storage, and client communication.
Core rules
- Dose = mg/kg × body weight in kg. Convert pounds first: kg = lb ÷ 2.2.
- Percentage to concentration: 1% = 10 mg/mL; 2.5% = 25 mg/mL. A 1:1000 solution = 1 mg/mL.
- Dilutions: C1 × V1 = C2 × V2.
- Verify every calculation twice, independently, and have a second person check high-risk drugs such as insulin, digoxin, chemotherapy agents, and potassium-containing fluids.
- Controlled substances are stored locked, logged at every use, and counted at shift change; federal DEA schedules II–V apply, and California adds its own recordkeeping and prescription requirements.
- Extra-label drug use requires a valid veterinarian-client-patient relationship and documented withdrawal times in food animals.
- Store vaccines refrigerated, protect light-sensitive drugs, never freeze products labeled for refrigeration, and discard expired stock. Shake suspensions before every dose.
Worked example
A 12 kg dog is prescribed amoxicillin 20 mg/kg PO every 12 hours for 10 days; the suspension is 50 mg/mL. Dose: 12 × 20 = 240 mg. Volume per dose: 240 ÷ 50 = 4.8 mL. Total doses: 2 per day × 10 days = 20. Total volume: 4.8 × 20 = 96 mL. Dispense a 100 mL bottle and label it: “Give 4.8 mL by mouth every 12 hours for 10 days. Shake well; refrigerate.”
Traps that cost marks
- Mixing mg/kg with mg/lb produces a 2.2-fold error, usually an overdose.
- Reading “2.5%” as 2.5 mg/mL instead of 25 mg/mL.
- Forgetting to shake a suspension or checking the concentration on the stock bottle rather than the dispensed bottle.
- Missing interactions such as NSAID plus corticosteroid, or an ACE inhibitor plus a potassium-sparing diuretic.
- Failing to log a controlled substance or to reconcile the bottle count at shift change.