VTNE Veterinary Pharmacology Questions and Answers

Question 1

A veterinarian prescribes phenobarbital for a 5-year-old dog diagnosed with idiopathic epilepsy. What is the primary mechanism of action for this drug?

Accepted Answer

Enhancing the effect of the inhibitory neurotransmitter GABA

Answer

Phenobarbital, a barbiturate anticonvulsant, primarily works by potentiating the effect of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the central nervous system. It binds to GABA-A receptors, which increases the duration of chloride channel opening, leading to hyperpolarization of the cell membrane and reduced neuronal excitability.

Question 2

A 12-kg dog is prescribed carprofen for osteoarthritis at a dose of 2.2 mg/kg BID. The clinic stocks 50 mg scored tablets. How many tablets should be dispensed for a 10-day supply?

Accepted Answer

10 tablets

Answer

First, calculate the single dose in mg: 12 kg * 2.2 mg/kg = 26.4 mg. Since the tablets are 50 mg and scored, the dog will receive a half tablet (25 mg) per dose. The dosing is BID (twice a day), so the dog needs 2 doses per day. For a 10-day supply, the total number of doses is 2 doses/day * 10 days = 20 doses. Since each dose is a half tablet, the total number of tablets is 20 doses * 0.5 tablets/dose = 10 tablets.

Question 3

Which of the following is a common, and potentially serious, class-wide side effect of non-steroidal anti-inflammatory drugs (NSAIDs) in dogs?

Accepted Answer

Gastrointestinal ulceration

Answer

NSAIDs work by inhibiting cyclooxygenase (COX) enzymes, which reduces the production of prostaglandins. While this decreases inflammation and pain, it also reduces the production of prostaglandins that protect the stomach and intestinal lining. This can lead to gastrointestinal irritation, ulceration, and even perforation, which is a major risk associated with NSAID use.

Question 4

A Collie presents with severe neurological signs, including ataxia and seizures, after receiving a high dose of ivermectin for mange treatment. This adverse reaction is most likely due to a mutation in which gene?

Accepted Answer

MDR1 (ABCB1)

Answer

Certain breeds, particularly Collies and related breeds, can have a mutation in the Multidrug Resistance Gene (MDR1), also known as the ABCB1 gene. This gene codes for P-glycoprotein, a transport pump that is part of the blood-brain barrier and actively removes certain drugs, like ivermectin, from the brain. A defective gene leads to the accumulation of the drug in the central nervous system, causing neurotoxicity.

Question 5

Maropitant (Cerenia®) is a widely used antiemetic in veterinary medicine. It provides broad-spectrum anti-vomiting effects by acting as a:

Accepted Answer

Neurokinin-1 (NK-1) receptor antagonist

Answer

Maropitant is a potent and selective antagonist of the Neurokinin-1 (NK-1) receptor. It works by blocking the binding of Substance P, a key neurotransmitter involved in the vomiting reflex, at the NK-1 receptors in the emetic center of the brain. This mechanism makes it effective against vomiting triggered by both central and peripheral stimuli.

VTNE - Veterinary Technician National Examination Practice Test

VTNE - Veterinary Technician National Examination Practice Test

VTNE Veterinary Pharmacology Questions and Answers