Pharmacy and Pharmacology
Core concepts
Pharmacology questions test whether you can link a drug's mechanism to its clinical effect and its hazards. Know the four pharmacokinetic phases - absorption, distribution, metabolism, and excretion - and the terms built on them: bioavailability, first-pass hepatic metabolism, volume of distribution, half-life, and steady state (reached in roughly 4–5 half-lives). Most drugs are hepatically metabolized and renally excreted, so organ disease usually changes the dosing interval more than the individual dose.
Class knowledge
Be able to place common agents in their class and name the signature adverse effect: NSAIDs (COX inhibition; GI and renal risk), opioids (pure agonists vs partial agonists vs agonist-antagonists), corticosteroids, antimicrobials (bactericidal vs bacteriostatic; culture and susceptibility when possible), antiparasitics, antiemetics, and cardiac drugs. Species differences are heavily tested: cats have limited glucuronidation, permethrin spot-ons are toxic to cats, and MDR1/ABCB1-mutant dogs may react severely to ivermectin-type drugs.
Calculations and handling
Convert everything to consistent units and ask three questions: what is the dose, what is the concentration, and what is the patient's weight? Doses are per kg; concentrations are per mL. Also know storage requirements (refrigeration, light protection), controlled-substance logging, and withdrawal times in food animals.
Worked example
A 12 kg dog is prescribed 5 mg/kg of a drug supplied as 50 mg/mL. Dose = 12 × 5 = 60 mg. Volume = 60 ÷ 50 = 1.2 mL.
Traps
Mixing up mg and mL, dosing by pounds instead of kilograms, forgetting maximum doses, and assuming a drug safe in dogs is safe in cats.