Free DVM Doctor of Veterinary Medicine Veterinary Pharmacology and Therapeutics Questions and Answers — Questions and Answers
Question 1: A 10-year-old Cavalier King Charles Spaniel with known degenerative mitral valve disease presents with an acute onset of coughing and a respiratory rate of 80 breaths/min. Radiographs confirm cardiogenic pulmonary edema. In addition to oxygen therapy, which of the following drugs is most critical for immediate intravenous administration to reduce preload and alleviate the edema?
- Furosemide (Correct answer)
- Pimobendan
- Enalapril
- Spironolactone
Correct answer: Furosemide
Furosemide is a potent loop diuretic that acts quickly to promote diuresis, which reduces circulating blood volume and venous pressure (preload). This action directly alleviates the fluid accumulation in the lungs (pulmonary edema) characteristic of acute congestive heart failure. While pimobendan and enalapril are crucial for long-term management, furosemide provides the most immediate and life-saving relief in this acute crisis. Spironolactone is a much weaker, potassium-sparing diuretic used for chronic management.
Question 2: Which of the following antimicrobial drugs is strictly contraindicated for use in growing large-breed dogs due to its potential to cause irreversible damage to articular cartilage?
- Amoxicillin-clavulanate
- Doxycycline
- Metronidazole
- Enrofloxacin (Correct answer)
Correct answer: Enrofloxacin
Enrofloxacin, a member of the fluoroquinolone class, has been shown to cause arthropathy, characterized by erosions in the articular cartilage of weight-bearing joints in growing animals. This effect makes its use contraindicated in small and medium breed dogs between 2 and 8 months of age and in large and giant breeds for up to 18 months. The other listed antibiotics do not carry this specific contraindication.
Question 3: A dog is presented to the emergency clinic after ingesting an unknown quantity of an anticoagulant rodenticide approximately 2 hours ago. The dog is currently asymptomatic. Which of the following therapeutic plans is most appropriate for immediate management?
- Administer Vitamin K1 immediately and discharge with a 4-week course of the same.
- Induce emesis, administer activated charcoal, and begin Vitamin K1 therapy. (Correct answer)
- Perform baseline coagulation testing and start Vitamin K1 only if values are abnormal.
- Administer a fresh frozen plasma transfusion and monitor for signs of bleeding.
Correct answer: Induce emesis, administer activated charcoal, and begin Vitamin K1 therapy.
For a recent (within 2-4 hours) ingestion of an anticoagulant rodenticide, the primary goal is decontamination to prevent absorption. This is best achieved by inducing emesis followed by administering activated charcoal to bind any remaining toxin. Although the dog is asymptomatic, the peak effect of these toxins is delayed 3-5 days, so initiating the antidote, Vitamin K1, is crucial to counteract the inhibition of clotting factor synthesis. Waiting for clinical signs or abnormal coagulation times is inappropriate, and transfusions are only indicated if the animal is actively bleeding.
Question 4: A 14-year-old cat with stable chronic kidney disease (IRIS Stage 2) and painful osteoarthritis requires long-term analgesia. Which of the following non-steroidal anti-inflammatory drugs (NSAIDs) is generally considered to have a favorable safety profile and is licensed for long-term use in cats for this purpose in many regions?
- Carprofen
- Meloxicam
- Robenacoxib (Correct answer)
- Deracoxib
Correct answer: Robenacoxib
Robenacoxib is a highly COX-2 selective NSAID. Its pharmacokinetic profile in cats, including a short half-life in the blood but persistence at the site of inflammation, contributes to a favorable safety profile. Studies have shown it can be used with appropriate monitoring in cats with stable, early-stage chronic kidney disease. Carprofen and Deracoxib are not typically used for long-term pain management in cats. While Meloxicam is also used, Robenacoxib is a well-supported choice for long-term management of OA in cats, including those with stable comorbidities.
Question 5: What is the primary mechanism of action for the isoxazoline class of drugs (e.g., fluralaner, afoxolaner), which are commonly used for flea and tick control in dogs and cats?
- Agonist of nicotinic acetylcholine receptors, causing spastic paralysis.
- Inhibition of acetylcholinesterase, leading to neuromuscular overstimulation.
- Disruption of microtubule formation in parasite intestinal cells.
- Non-competitive antagonist of GABA- and glutamate-gated chloride channels. (Correct answer)
Correct answer: Non-competitive antagonist of GABA- and glutamate-gated chloride channels.
The isoxazoline class of ectoparasiticides works by non-competitively blocking GABA (gamma-aminobutyric acid)-gated and glutamate-gated chloride channels in the nervous systems of insects and acarines. This blockade prevents the influx of chloride ions, leading to hyperexcitation, uncontrolled nerve activity, and rapid death of the parasite. This mechanism is highly selective for invertebrates, providing a wide margin of safety in mammals.
Question 6: Doxorubicin is a common chemotherapeutic agent used in veterinary oncology. Which of the following is a well-documented, cumulative, and often dose-limiting cardiotoxicity specifically associated with this drug in dogs?
- Dilated cardiomyopathy (DCM) (Correct answer)
- Acute arrhythmogenic toxicity
- Pericardial effusion
- Valvular endocardiosis
Correct answer: Dilated cardiomyopathy (DCM)
Doxorubicin is known to cause a cumulative, dose-dependent cardiotoxicity in dogs that manifests as dilated cardiomyopathy (DCM). The damage to the myocardium is caused by free radical formation and oxidative stress. This is why a patient's cumulative lifetime dose is carefully tracked, and cardiac evaluations are often performed. While acute arrhythmias can occur during infusion, the chronic, dose-limiting toxicity that leads to heart failure is DCM.
Free DVM Doctor of Veterinary Medicine Veterinary Pharmacology and Therapeutics Questions and Answers
A 10-year-old Cavalier King Charles Spaniel with known degenerative mitral valve disease presents with an acute onset of coughing and a respiratory rate of 80 breaths/min.
Radiographs confirm cardiogenic pulmonary edema.
In addition to oxygen therapy, which of the following drugs is most critical for immediate intravenous administration to reduce preload and alleviate the edema?