Congestive heart failure (CHF) refers to the heart’s inability to pump adequate blood to the body. There are many causes of CHF in dogs. The two most common causes are mitral valve insufficiency (MVI), or a leaky mitral valve, and dilated cardiomyopathy (DCM). The most common clinical sign of CHF is persistent coughing accompanied by difficulty breathing. Other signs include coughing when at rest or sleeping, an increased resting respiratory rate or excessive panting, persistent loss of appetite, a swollen belly, and pale or bluish gums.

Cholecalciferol (vitamin D3) has become increasingly more common as a residential rodenticide. While it may seem like a safer option than anticoagulants, there is no antidote available and the amount in a single block is a severe overdose in nearly all animals. This handout discusses clinical signs, treatments, and prognosis for cholecalciferol poisoning in pets.

Chocolate is toxic to dogs. While rarely fatal, chocolate ingestion often results in significant illness. Chocolate is toxic because it contains the alkaloid theobromine. Theobromine is like caffeine and is used medicinally as a diuretic, heart stimulant, blood vessel dilator, and muscle relaxant.

Chlorfenapyr poisoning is suspected if a pet has access to this pesticide and subsequently develops expected signs; it should also be suspected in a pet exhibiting signs and at risk of malicious poisoning. Pets that develop clinical signs following chlorfenapyr ingestion are unlikely to survive and chronic complications may be present for survivors.

Chemotherapy drugs are used to treat cancer and other conditions in people because they target and kill rapidly dividing neoplastic (cancer) cells and other cells. They are primarily used as anti-cancer agents but may also provide benefits for a variety of auto-immune disorders and organ transplant recipients as immunosuppressive agents.