Pharmacy and Pharmacology
Domain focus
Pharmacy and Pharmacology tests how well you calculate, prepare, dispense, and monitor drug therapy. Questions often combine a drug class with a patient scenario: choosing an antibiotic, recognizing an adverse effect, or converting a dose to a syringe volume.
Core rules and concepts
- The dose formula is body weight in kilograms multiplied by the dose rate in mg/kg. The volume to draw is the dose divided by the concentration in mg/mL.
- Percentage concentrations are a common source of error: 1% = 10 mg/mL, 2% = 20 mg/mL, and 0.5% = 5 mg/mL.
- Pharmacokinetics describes absorption, distribution, metabolism, and excretion. Pharmacodynamics describes what the drug does at the receptor.
- Controlled substances require secure storage, a running inventory, and accurate records. Vaccines and some biologics need continuous refrigeration; do not freeze them unless the label permits it.
- Extra-label use is a veterinarian's decision, not a technician's, and it changes withdrawal-time considerations in food-producing animals.
Worked example
A 12 kg dog is prescribed 5 mg/kg of an oral suspension labeled 50 mg/mL. Dose = 12 kg × 5 mg/kg = 60 mg. Volume = 60 mg ÷ 50 mg/mL = 1.2 mL. The technician draws 1.2 mL and confirms the owner has an oral syringe and understands shaking the bottle.
Traps that cost marks
Mixing mg/kg with mg/lb; misplacing a decimal; treating 1:1000 epinephrine as 1 mg/mL is correct, but 1:10,000 is 0.1 mg/mL; failing to shake suspensions; and combining drugs that are chemically incompatible in the same syringe.