ICVA Feline Pharmacology and Toxicology 4

Question 1

Which antiparasitic drug is safe to use in cats at antiparasitic doses but causes toxicity at high doses due to P-glycoprotein substrate status?

Accepted Answer

Ivermectin

Answer

Ivermectin is a P-gp substrate; while cats generally express functional MDR1/ABCB1 and tolerate antiparasitic doses, high doses can overwhelm the blood-brain barrier protection causing CNS toxicity.

Question 2

A cat receiving chlorambucil for IBD develops acute cerebellar signs. What is the likely cause?

Accepted Answer

Chlorambucil-induced neurotoxicity

Answer

Chlorambucil can cause reversible neurotoxicity (tremors, myoclonus, seizures) in cats, particularly at higher doses; dose reduction or discontinuation typically resolves signs.

Question 3

Which antibiotic is associated with fatal hepatic necrosis in cats and should be avoided?

Accepted Answer

Tetracycline

Answer

Tetracyclines, especially doxycycline, can cause esophageal strictures and hepatotoxicity in cats; oral tablets must always be followed with a water bolus to prevent esophageal damage.

Question 4

What is the primary risk of administering xylazine to cats compared to dogs?

Accepted Answer

Cats are more sensitive and show profound cardiovascular depression at lower doses

Answer

Cats are approximately 10 times more sensitive to xylazine than dogs, achieving deep sedation at doses that cause only mild sedation in dogs, along with significant cardiovascular and respiratory depression.

Question 5

Which drug used in cats for urethral spasm has sympathomimetic properties that can cause hypertension?

Accepted Answer

Pseudoephedrine

Answer

Pseudoephedrine, while occasionally used off-label for urinary incontinence, is a sympathomimetic that can cause hypertension, tachycardia, and CNS stimulation in cats.

(ICVA) International Council for Veterinary Assessment Practice Test

(ICVA) International Council for Veterinary Assessment Practice Test

ICVA Feline Pharmacology and Toxicology 4