Pharmacy and Pharmacology
What the exam tests
Pharmacy and Pharmacology asks you to connect drug class, mechanism, route, dose calculation, and legal handling. Expect calculation items, adverse-effect recognition, and client-safety teaching.
Core rules
- Pharmacokinetics: absorption, distribution, hepatic metabolism, renal excretion; half-life sets dosing interval.
- Know classes: NSAIDs (COX inhibition), opioids, alpha-2 agonists, benzodiazepines, antimicrobials, and antiparasitics.
- Dose formula: total dose (mg) = dose (mg/kg) × body weight (kg). Volume (mL) = total dose (mg) ÷ concentration (mg/mL).
- A 1% solution is 10 mg/mL; 2% is 20 mg/mL. Convert pounds to kilograms by dividing by 2.2.
- Controlled substances require DEA registration, secure storage, and a running inventory log.
Worked example
A 12 kg dog is prescribed 5 mg/kg of a 50 mg/mL solution. Total dose = 5 × 12 = 60 mg. Volume = 60 ÷ 50 = 1.2 mL. If the same dog received a 2% solution, 2% = 20 mg/mL, so volume = 60 ÷ 20 = 3 mL. The arithmetic is identical; only the concentration changes.
Traps
- Mixing mg/kg with mg/lb; a 22 lb dog is 10 kg, not 22 kg.
- Forgetting that percentage concentrations are weight/volume, not mg per mL directly.
- Splitting or crushing enteric-coated or extended-release tablets.
- Missing species sensitivities: permethrin toxicity in cats, xylitol in dogs, and NSAID caution in renal or GI disease.
- Dispensing without checking withdrawal time in food animals.