Chemotherapy for Pets with Cancer

Chemotherapy for Pets with Cancer

Hearing your pets diagnosed with cancer is by far one of the worst moments that a pet owner can experience. Once you manage to get past the initial shock of hearing the dreaded c-word, you will almost certainly want to know what options your pet has regarding treatment. Most people have heard of chemotherapy for humans; however, it may surprise you to learn that chemotherapy treatment is also often offered as a possible treatment for our pets.

If you or someone you know has previously gone through chemotherapy and you have experience of just how debilitating it can potentially be, it is understandable that you might be reluctant to put your pet through the same process. The good news, however, is that most pets actually deal with chemotherapy far better than their human counterparts.

While certain cancers are very sensitive to chemotherapy and the treatment has been shown to be very effective, other types of cancer do not respond to chemotherapy medications at all. It is therefore important to remember that chemotherapy will only ever be recommended where our experienced veterinarians believe that it has the best chance at destroying the type of cancer your pet has and/or enhancing your pet’s quality of life.

sick dog

How does chemotherapy work?

Chemotherapy drug work by attacking cells in your pet’s body that are rapidly dividing and reproducing – a key characteristic of cancer cells. The drug is either given intravenously or administered via an oral tablet. If given intravenously, your pet may need to be sedated to keep her calm and relaxed as although it isn’t painful, we will need to be sure that your pet remains still while the intravenous needle is in place.

Exactly how many doses of chemotherapy your pet will need will depend on her individual circumstances. We may be able to give you an approximate indication at the time of diagnosis, but this is subject to change based on how she responds to the treatment.

What are the side effects of chemotherapy for pets with cancer?

Although animals tend to deal with chemotherapy much better than humans, this doesn’t mean that they will completely avoid any side effects. Our veterinary team will closely monitor the effect that chemotherapy is having on your furbaby, plus give you an indication as to what you should watch out for at home that might indicate your pet needs professional assistance.

The three most common side effects of chemotherapy in pets are as follows:


You are probably familiar with hair loss as a side effect of chemotherapy. While it isn’t all that common in pets, it can happen, and certain breeds are more likely to experience hair than others. These include breeds with continuously growing hair such as Shih Tzus, Maltese, and Poodles. Any hair loss that does occur may grow back over time, but the color and thickness of the hair can change – sometimes permanently.

Gastrointestinal problems

Unfortunately, gastrointestinal problems are a common side effect of chemotherapy and issues like vomiting and diarrhea can occur in the first few days after each chemo session. It can be helpful to change your pet’s diet to plain foods such as boiled chicken and rice which will be easier for her to digest. It may also be possible for us to give your pet some medications to ease any sickness or bowel issues that arise as a result of the chemotherapy.

Bone marrow suppression

We know that chemotherapy targets cells that divide and reproduce at an unprecedented rate. However, there are also perfectly good cells in your pet’s body that do that too, and sometimes the chemotherapy drugs may attack these good cells by mistake. White blood cell and red blood cell production can become repressed during chemotherapy for this reason. If your pet’s white blood cell count becomes too repressed at this time, it may be necessary for your vet to prescribe antibiotics to counteract any infection risk caused by poor immunity.

When we recommend chemotherapy to our patients, we do with the intention of prolonging your pet’s life and to enable them to maintain a good quality of life while they are undergoing treatment. If you have any further questions about chemotherapy for pets, please don’t hesitate to get in touch with our knowledgeable and reassuring animal cancer care specialists at either of our clinics.