ecent advancements in canine chemotherapy have turned what used to be a terminal cancer diagnosis into viable treatment paths, offering a glimmer of hope for pet owners. However, adverse reactions to chemotherapy are common.
Eighty percent of dogs undergoing treatment experience at least one side effect and 32% suffer from serious reactions. Specific symptoms usually depend on the drug being used and how aggressive the treatment is, along with the age and health of the dog.
While most side effects are mild and require only monitoring or light treatment, some can be life-threatening and result in hospitalization, and possibly an end to the cancer regimen.
The following are the three main areas where adverse effects of chemo can occur and the signs to be aware of.
Treating hair loss brought on by chemo in dogs is fairly straightforward. Regardless of the severity of the thinning, the dog will likely need a haircut to even out its coat. If shedding or patching are bad enough to impact the aesthetic or cause discomfort for the dog, shaving may be the best option. Ultimately, the decision is up to the owner.
Monitoring is the most important step to take in keeping blood cells at a healthy amount. The veterinary oncologist often prescribes antibiotics as a boost to the immune system if white blood cell counts begin to dip. If red blood cell levels are looking low, the dog may require a blood transfusion to prevent more serious issues and potential hospitalization.
As with blood cell counts, the most important step in managing digestive issues caused by chemotherapy is monitoring. Open communication between vets, owners, and caretakers about patterns in appetite and stool is critical. If a dog is experiencing a decrease in appetite, new options in making the dog’s food more appealing can be pursued, such as heating food to body temperature in the microwave, or enhancing the dog’s diet with low-sodium broth or home-cooked alternatives. Appetite stimulants are also available via prescription from the pet’s veterinarian.
Since the animal is already weakened by cancer and chemotherapy treatment, anorexia can quickly turn dangerous and require hospitalization. In drastic situations, a dog may require a feeding tube or IV to avoid starvation.
Vomiting and CID are both common and important to stay on top of, as both symptoms can lead to potentially deadly dehydration and halt the chemo regimen. There are effective anti-emetic (anti-vomiting) medications that are fast-acting and crucial for certain chemotherapy protocols. Vomiting can happen quickly after the chemotherapy dosing starts, but sometimes dogs need to be on anti-emetics even at the time of chemo treatment to be sure it can occur without the dog having a reaction.
Unlike vomiting, which happens immediately, CID can occur hours or days following a chemo dose. Owners and caretakers will need to monitor the pet and make sure that if the dog is exhibiting CID, the animal is drinking extra water to compensate. There is also a newer medication that can be prescribed by the pet’s veterinarian which normalizes fluid influx in the GI tract. Both methods are great steps to diminish likelihood of a trip to the hospital for rehydration via IV.
Improving a dog’s health after a cancer diagnosis is a constant battle, and even the best possible treatment plan can cause adverse symptoms. However, by being aware of the side effects of chemotherapy and maintaining close communication with the dog’s owner and veterinarian, you can play a part in helping the dog successfully navigate their cancer treatment.
Andre Teixeira, DVM, Ph.D., received his DVM degree in 2009 and then his Ph.D. degree in Animal Science. He joined Jaguar Health’s team in June 2017, bringing nearly 10 years of experience in animal pharmaceutical development. He now serves as the Sr. Director of Animal Health and is responsible for the development of animal health clinical studies, protocols and publications.