Treating inappetence in dogs

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Inappetence in pets can be challenging for both pet owners and veterinarians to identify. To simplify this process, Sue Ettinger, DVM, DACVIM (Oncology), breaks inappetence into 3 categories—true inappetence, pseudo-inappetence, and secondary inappetence as she explained in a dvm360 interview.

True inappetence occurs when a pet is in a new or stressful environment, such as a boarding facility or hospital. Pseudo-inappetence is when an animal can’t prehend food, such as from oral disease or dysphagia, so they cannot physically get it into their mouth. However, secondary inappetence is the one Ettinger says she sees most in practice, and it is associated with conditions such as cancer, kidney disease, or heart disease, as well as those medications used for treatment that cause appetite loss.

Laura Gaylord, DVM, DACVIM (Nutrition), also noted that secondary inappetence is what she is presented with most often, as inappetence is frequently linked to a medical condition. “I would emphasize that picky eating or inappetence is a medical problem, not a nutritional problem,” she said in a dvm360 interview. “It’s super common that people just want to change the food, but...you need to get to the bottom of what the underlying cause is that’s creating inappetence to begin with. Doing a good medical work-up is super important to identify what we can do medically to solve that problem.”

Treating inappetence

One challenge that can arise when treating inappetence is an insufficient medical work-up due to an unknown underlying disease causing it, according to Gaylord. Additionally, a complete medical work-up can indicate whether a patient is suffering from more than 1 condition so they can be treated with a multimodal approach to address all factors contributing to appetite loss.

“Treating inappetence can be a collection of strategies,” Gaylord said. “So maybe changing the diet [to a] rotation diet [or a] palatable diet is one aspect, but we also should be thinking about medications. It’s OK to use medications. I get clients [who] are hesitant to use appetite stimulants or other medications, and I feel totally [the] opposite. I [think you should] use everything you have.”

One of the most common treatments for inappetence is maropitant citrate, although Ettinger emphasized that this drug is an antiemetic medication that treats nausea and vomiting, not necessarily inappetence. She recommended giving pets ghrelin receptor agonists, such as capromorelin for dogs and capromorelin oral solution for cats, that mimic the hunger hormone if they are strictly experiencing appetite loss. Other effective drugs she listed include mirtazapine (which comes in an ointment form for easy administration), ondansetron, and dolasetron. Gaylord added that a traditional therapy such as diazepam is another option that can be given as a short-term appetite stimulant. Both Ettinger and Gaylord stressed the importance of identifying the underlying cause of the inappetence to select the best medications and to appropriately treat the pet.

Cancer-related inappetence

Because all kinds of cancers in dogs and cats are often associated with inappetence and weight loss,^1,2 Ettinger and Gaylord also provided their insight on how to specifically approach this kind of patient. Clinical signs of inappetence related to cancer are decreased food consumption, weight loss, muscle wasting, lip smacking, vomiting, poor hair coat, and behavior changes.³

The most common behavior change Ettinger is presented with is the pet approaching the bowl as if it’s hungry, then turning away without eating.³ This is serious, as inappetence can result in weight loss, cachexia, metabolic derangements, and delayed wound healing, as well as decreased immune response, strength, gastrointestinal mucosal function, and survival time.^4-6

In addition to the cancer itself causing inappetence, oncology treatments including chemotherapy, radiation, and other medications can also lead to it. Ettinger said³ that following chemotherapy, she sends her client home with necessary medication to help improve their appetite and an information sheet outlining what to look for and how to manage adverse effects at home.

Nutritionists approach patients with cancer and inappetence from a different angle. “As a nutritionist, that’s where I might be using very palatable diets, [such as] canned foods or homemade diet recipes. I sometimes incorporate exchangeable options in there so they have some variety they can use. I am usually telling [clients that] what matters most for survival for these guys is maintaining good calorie [intake],” Gaylord said.

References

1. Gibeault S. Cancer in senior dogs: signs and symptoms to watch for. American Kennel Club. June 9, 2022. Accessed May 15, 2023. www.akc.org/expert-advice/health/ cancer-senior-dogs-signs-symptoms-to-watch-for
2. Patrick C. Cancer in cats: symptoms and treatment. American Society for the Prevention of Cruelty to Animals Pet Health Insurance. Accessed May 15, 2023. https:// www.aspcapetinsurance.com/resources/cancer-and-cats
3. Ettinger S. Take the offensive with patients fighting cancer and inappetence. dvm360. June 10, 2019. Accessed May 15, 2023. www.dvm360.com/view/take-offensive-with-pa- tients-fighting-cancer-and-inappetence
4. Forman MA. Anorexia. In: Ettinger SJ, Feldman EC, eds. Textbook of Veterinary Internal Medicine. 7th ed. Elsevier; 2010.
5. Zoran DL. Nutritional management of gastrointestinal conditions. In: Ettinger SJ, Feldman EC, eds. Textbook of Veterinary Internal Medicine. 7th ed. Elsevier; 2010.
6. Satyaraj E. Emerging paradigms in immunonutrition. Top Companion Anim Med. 2011;26(1):25-32. doi:10.1053/j. tcam.2011.01.004