NAVLE Veterinary Pharmacology 3 — Questions and Answers
Question 1: Which drug is used to reverse the sedative and analgesic effects of medetomidine in dogs and cats?
- Naloxone
- Flumazenil
- Atipamezole (Correct answer)
- Yohimbine
Correct answer: Atipamezole
Atipamezole is a specific alpha-2 adrenergic antagonist used to reverse medetomidine and dexmedetomidine sedation in dogs and cats.
Question 2: Which of the following best describes the pharmacokinetic term 'volume of distribution' (Vd)?
- The rate at which a drug is eliminated from the body
- A theoretical volume relating plasma drug concentration to total drug in the body (Correct answer)
- The fraction of an oral dose reaching systemic circulation
- The time for plasma drug concentration to decrease by 50%
Correct answer: A theoretical volume relating plasma drug concentration to total drug in the body
Volume of distribution is a theoretical volume that relates the total amount of drug in the body to the concentration measured in plasma.
Question 3: Aminoglycoside antibiotics (e.g., gentamicin) should be used with extreme caution in patients with which condition?
- Hepatic disease
- Renal insufficiency (Correct answer)
- Pulmonary disease
- Cardiac arrhythmias
Correct answer: Renal insufficiency
Aminoglycosides are nephrotoxic and require renal elimination; pre-existing renal insufficiency greatly increases the risk of drug accumulation and toxicity.
Question 4: A ferret with insulinoma is being treated medically. Which drug is used to increase blood glucose by inhibiting insulin secretion?
- Prednisolone
- Diazoxide (Correct answer)
- Methimazole
- Phenobarbital
Correct answer: Diazoxide
Diazoxide inhibits pancreatic insulin secretion and promotes glycogenolysis, making it useful for managing hypoglycemia in ferrets with insulinoma.
Question 5: Which fluoroquinolone is known to cause retinal degeneration in cats, particularly at high doses?
- Marbofloxacin
- Enrofloxacin (Correct answer)
- Pradofloxacin
- Ciprofloxacin
Correct answer: Enrofloxacin
Enrofloxacin at high doses has been associated with acute retinal degeneration and blindness in cats, and dosing must be carefully limited in this species.
Question 6: What is the primary mechanism by which ivermectin kills parasites?
- Inhibits acetylcholinesterase
- Potentiates glutamate-gated chloride channels causing paralysis (Correct answer)
- Disrupts parasite cell membrane integrity
- Blocks tubulin polymerization
Correct answer: Potentiates glutamate-gated chloride channels causing paralysis
Ivermectin potentiates glutamate-gated chloride channels in invertebrate nerve and muscle cells, causing hyperpolarization, paralysis, and death of the parasite.
Question 7: Which drug is used to treat hyperthyroidism in cats by blocking thyroid hormone synthesis?
- Radioactive iodine (I-131)
- Methimazole (Correct answer)
- Levothyroxine
- Propranolol
Correct answer: Methimazole
Methimazole inhibits thyroid peroxidase, thereby blocking the synthesis of thyroid hormones and is the most common medical management for feline hyperthyroidism.
NAVLE Veterinary Pharmacology 3
Which drug is used to reverse the sedative and analgesic effects of medetomidine in dogs and cats?