Chemotherapy Drug Poisoning in Dogs and Cats

What are chemotherapy drugs?

Chemotherapy drugs are medications primarily used to treat cancer in people and animals. They can also be used to treat autoimmune disorders, certain blood disorders, or as immunosuppressive agents in organ transplant recipients.

Many chemotherapy drugs target and kill rapidly dividing cancer cells, preventing them from multiplying out of control. Normal, healthy cells that also grow quickly can be damaged. Newer forms of chemotherapy may just target cancer cells, minimizing potential damage to healthy cells.

What causes chemotherapy drug poisoning in a dog or cat?

Chemotherapy medications are available in injectable, oral, or topical formulations. Animals may be exposed to these medications in the home by ingesting them if they are dropped or spilled, by licking a topical medication after application, or by chewing into the medication container.

What are the signs of chemotherapy drug poisoning in a dog or cat?

Signs following an exposure can vary, depending on the type of chemotherapy drug and the species exposed. Stomach upset is common and may include decreased appetite and abdominal pain. Some drugs may cause neurologic signs such as tremors and seizures. 

Damage to bone marrow may develop days to weeks after ingestion, resulting in low numbers of white blood cells, red blood cells, and/or platelets. Bone marrow suppression puts pets at an increased risk of infections. Chemotherapy medications can also damage other organs, including the liver, kidneys, heart, pancreas, and lungs.

How is poisoning with chemotherapy drugs treated?

As with all poisonings, early intervention is key to successful treatment. Call your veterinarian or Pet Poison Helpline, a 24/7 animal poison control center, at 1-800-213-6680, as soon as you realize your pet has been exposed to a chemotherapy drug. Your pet’s veterinarian may induce vomiting to help remove the toxin from the system before it is absorbed and may also give medical-grade activated charcoal to minimize absorption of any remaining toxin from the gastrointestinal tract.

Supportive therapy includes fluid support and medications to treat the pet’s clinical signs. Hospitalization may be needed. Blood work may be done to monitor organ function and blood cell counts. To treat bone marrow suppression, blood transfusions, drugs to stimulate red blood cell production, and antibiotics may be needed.

Pet Poison Helpline, an animal poison control center based out of Minneapolis, MN, is available 24/7 for pet owners and veterinary professionals that require assistance treating a potentially poisoned pet. The staff provides treatment advice for poisoning cases of all species, including dogs, cats, birds, small mammals, large animals, and exotic species. As the most cost-effective option for animal poison control care, Pet Poison Helpline’s per-incident fee includes follow-up consultations for the duration of the poison case. Pet Poison Helpline is available in North America by calling 800-213-6680. Additional information can be found online at www.petpoisonhelpline.com.