Guidelines for Dealing with Your Dog's Chemotherapy Side Effects - Dog Cancer Blog

Featuring Demian Dressler, DVM and Susan Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide.

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Guidelines for Dealing with Your Dog’s Chemotherapy Side Effects

chemo-side-effectsAs I’ve discussed in other posts, chemotherapy is very well tolerated in dogs.

Yes I know that is hard to believe. I have had family members get chemo and we have all seen it on TV, but happily it’s not like that for dogs.

Approximately 80% of dogs do not have side effects at all … and about 15-20% will have mild to moderate side effects.

Today we will discuss how you can help identify and manage GI related side effects after chemotherapy treatment.


How do I tell if my pet is nauseous? Nausea is often manifested by decreased appetite, drooling, or your pet approaching the food as if he or she is hungry … but then not actually eating. (Think about how the smell of food can make you nauseous when you are not feeling well.)

What do I do?

  • First, don’t feed your dog for now, but offer ice cubes every few hours.
  • Start anti-nausea medication as prescribed. I typically send my patients home with Cerenia® at the 1st chemo visit. But other options include metaclopromide (Reglan®), mirtazapine, or Zofran®.  I think you should have these on hand at home.
  • After 12 hours, feed very small but frequent meals (not one large meal).
  • Call your veterinarian if nausea persists for more than 24 hours.


Here’s what to do if your dog is vomiting.

  • No food and water for 12-24 hours.
  • If the vomiting is mild (one or two episodes), start the anti-vomiting/anti-nausea medication as prescribed (Cerenia®, metaclopromide (Reglan®), or Zofran®).
  • If there is no vomiting for 12-24 hours, offer small amounts of water or ice cubes.
  • If your pet does not vomit after drinking the water over the next 12-24 hours, offer small amounts of bland diet.
  • What is a bland diet? Bland diet options include boiled chicken, lean meat, or cottage cheese, with rice, or a commercially prepared bland diet, such as Eukanuba Low Residue, Hills I/D.
  • If there is still no vomiting, gradually reintroduce your pet’s normal diet, mixing it in to the bland diet
  • Severe vomiting can lead to dehydration. If the vomiting is severe, persists for more than 24 hours, or is accompanied with a fever of greater than 103°F, please bring your pet to your oncologist, family veterinarian, and an emergency clinic.


Here’s what to do if your dog is experiencing diarrhea.

  • Offer the bland diet (as above) and fresh water.  When you switch back to your pet’s regular diet, wean them back gradually.
  • If you were sent home with an anti-diarrheal medication (such as metronidazole (Flagyl®), sulfasalzine, or Tylan®), start the medication as prescribed. Again, I think you should have these on hand, along with a probiotic.
  • I also recommend a probiotic for dogs with diarrhea.

Can I use over the counter (OTC) meds for diarrhea??

  • For dogs, Pepto-Bismol can be given. Pepto-Bismol® is also known by its generic name bismuth subsalicylate. It is a human OTC medication for diarrhea and a GI tract protectant. The dose is 2 to 2.5 ml for every 10 lbs up to every 6 hours. Do not exceed therapy for more than 5 days. There are 5 ml in a teaspoon. Side effects are uncommon, and included vomiting and stool discoloration. Refrigeration may improve palatability. This will discolor the stool (may make it black). Do not give Pepto-Bismol® to cats.
  • Loperamide, also known as Imodium®, is an opiate anti-diarrheal that decreases gut motility.  It is a human OTC medication.  It should be discontinued if diarrhea continues 48 hours after starting the medication. Contact your veterinarian if your pet experiences constipation, depression, or slowed heart or breathing rates while being treated with loperamide. It should not be used in Collies and Collie-type breeds due to sensitivity. Rarely it may cause CNS depression. Only use after approval from your veterinarian, as there are certain conditions in which this can be harmful, including respiratory disease, severe kidney disease, hypothyroidism, and Addisions. The dog dose is 0.2 mg/pound by mouth every 8 to 12 hours. It typically comes a 2 mg capsules and liquid 0.2 mg/ml.   So a 45 lb dogs should receive approximately a 2 mg tablet every 8 to 12 hours. Use in cats is controversial as may cause excessive excitement.
  • If the diarrhea is severe, bloody, or black, persists for more than 48 hours, or is accompanied with a fever of greater than 103°F,  please bring your pet to your oncologist, family veterinarian, and an emergency clinic.

Live longer, Live well,

Dr. Sue

Susan Ettinger, DVM. Dip. ACVIM (Oncology), Dr. Sue, Dr Sue is a boarded veterinary medical cancer specialist. As a Diplomate of the American College of Veterinary Internal Medicine (Oncology), she is one of approximately 400 board-certified veterinary specialists in medical oncology in North America. She is a book author, radio co-host, and an advocate of early cancer detection and raising cancer awareness. Along with Dr. Demian Dressler, Dr. Sue is the co-author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity.

  • john March 4, 2014, 8:10 am

    my dog has had 2 treatments for anal sac carcinoma with carboplatin. her second, last dec. 2013, resulted in a severe reaction from which my dog almost died. in fact, my dogs primary vet and her oncologist expected my dog to die. she’s recovered. her white cells and t-cells were dangerously low for sometime. her platelets are in the low range of normal and may never come fully back to what thye were. in hindsight i would have gotten a second opinion regarding the carboplatin; and, knowing what i know now i at least would have asked the vet to start with low doses to see how my dog would react.

  • Mary Straus March 5, 2014, 2:31 pm

    I’m confused by something you wrote about Loperamide:

    “The dog dose is 0.2 mg/pound by mouth every 8 to 12 hours. It typically
    comes a 2 mg capsules and liquid 0.2 mg/ml. So a 45 lb dogs should
    receive approximately a 2 mg tablet every 8 to 12 hours.”

    At 0.2 mg/pound, the dosage for a 45-lb dog would be 9 mg, not 2 mg. Could you clarify?

  • Debbie Downey March 9, 2014, 12:15 pm

    I have a giant schnauzer diagnosed 2 weeks ago with Lymphoma. She has had the first dose of Vincristine. She has multiple LN involvement but there appears to be no spread to organs. She had no symptoms except for swollen nodes. The SM node was the side of a walnut when we had the first chemo dose. On day 4 the SM node was pecan sized on day 6 slightly smaller than almond size. Is this a normal response to therapy. No side effect…. I would like to think that this is a good sign that she is responding well???

  • asena basak September 5, 2018, 6:37 am

    My 13 year old golden retriever Marley was diagnosed with lymphoma on April 24th, 2018. We are now into September and hanging in…I’m very confused about the next urgent decision I have to make in this journey.
    Marley has been on CHOP protocol and completed an initial round of 5 treatments (rotating cyclophosphamide, doxorubicin, vincristine) and prednisolone. He’s been in remission starting from second week but he was hospitalized for two days after a cyclophosphamide dosage due to low white blood cells and fever…after I got him out of the hospital, we kept going, and qualified for half body radiation, which we did even though we were told there was a chance of low tolerance to chemo after radiation. Marley has been a soldier through this and took on 4 more treatments of chemo after the two half body radiation treatments but got extremely sick after a dose of doxorubicin, his fever went up to 106.7 and was in the hospital for two days. We came close to losing him. Now, we are finishing up our third week recovering from that episode and doing great. Marley is back to his old self. BUT We immediately need to decide whether we should continue with chemotherapy and finish the protocol..or not. The oncologist says the only medicine he didn’t react to is vincristine so he could give that one next and he has some alternative medicines from CHOP protocol to follow up with after that. Marley is in remission now. On chemo he is miserable, lethargic, picky with food and often has gastro issues. Can you please help us? Should we push through the 8 remaining chemotherapy treatments and hope for the best or do we stop now and enjoy a happy Marley enjoying life? Thank you so much

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