Managing Pet Chemotherapy Side Effects
Chemotherapy side effects, if they occur at all, tend to be very mild for dogs and cats. Lucerne Veterinary Hospital would not offer such treatments if they made our patients miserable. Cancer treatments at our hospital are designed to extend life and keep pets happy for as long as possible.
How Pet Chemotherapy Works
Cancer cells divide at an abnormally high rate, and chemotherapy drugs target this rapid division. There are some normal cells in the body that also divide rapidly, so side effects are related to the temporary depletion of these cells. If your pet has difficulty with any drug, however, we reassess to determine the best course of action, such as lower doses or drug changes.
Types of Side Effects
Chemo side effects generally fall into three categories:
- Vomiting, diarrhea, and loss of appetite—The cells that line the GI tract are examples of normal rapidly dividing cells that can be affected by chemotherapy. When this happens, the resulting signs are generally vomiting, diarrhea, and loss of appetite. Many pets do not experience these side effects at all, but if needed, there are a number of very good drugs that we can use to avoid or treat this.
- Hair loss or poor regrowth—The cells involved in hair growth are rapidly dividing, and this is why humans receiving chemo tend to lose their hair. Because of the way the hair grows in most pets though, we don’t see hair loss like we do in humans. While a few breeds of dog may be more susceptible, this is not a typical problem. If the pet has a shaved area from surgery or ultrasound, it may be slow to grow back, but the overall appearance of your dog will be the same throughout chemo.
- Low white blood cell, platelet, or red blood cell count—Cells in the blood come from special cells in the bone marrow, which are rapidly dividing and hence potentially affected by chemo. The bone marrow cells normally replace red and white blood cells, as well as platelets, the cells involved in clotting blood.
- Red blood cells are minimally affected by chemo; therefore, if anemia develops in a patient, it is generally very mild.
- Infection-fighting white blood cells can be depleted by chemo, suppressing the immune system and leaving the patient susceptible to infection. We perform a complete blood count (CBC) before each session to ensure that cell counts are sufficient to tolerate the next dose. While uncommon, if white blood cells drop too low, we may reduce doses or postpone chemo; this allows the bone marrow to catch up and reduces the risk for serious infection.
- Platelets can also be affected by chemo; the CBC as described above will also tell us if the platelet count is sufficient.
One of the most dangerous side effects of chemotherapy is sepsis, a system-wide infection that can occur if the white blood cell count gets too low. Thankfully, this is extremely rare and every precaution is taken to avoid it.
Every patient is sent home with written instructions after each chemotherapy appointment. Of course, you may contact us at any time if you have a concern or question.