What Is Inappetence?

Inappetence is a common complaint with varying levels of appetite reduction. It is most often associated with anorexia, or a complete lack of eating. More frequently, however, patients seen in clinic may be suffering from:

• Hyporexia: decrease in eating

• Dysrexia: altered patterns of eating

Early recognition of any changes in appetite is essential, as prolonged inappetence, if left untreated, can become more detrimental to the patient than the underlying primary condition.

Inappetence has three types: hyporexia (decrease in eating), dysrexia (altered patterns of eating), and anorexia (complete lack of eating)

Causes of Inappetence

The causes of inappetence are numerous and can be due to physical problems affecting eating. Some dogs may choose not to eat due to an unpalatable diet. Dogs can also develop food aversions.

In addition, if a dog cannot smell due to disease such as an upper respiratory tract infection, they are often unlikely to eat. Systemic disease can also cause inappetence in a multitude of ways. Specifically, chronic illnesses including kidney disease, gastrointestinal disease, heart disease, and cancer, as well as nausea, fever, pain, respiratory disease or medications can be involved.

Chronic or Systemic Conditions

  • Aging
  • Autoimmune disease
  • Cancer
  • Endocrine disease
  • Gastrointestinal disease
  • Heart disease
  • Infectious disease
  • Kidney disease
  • Medications
  • Nasal disease
  • Neurologic disease
  • Pain
  • Respiratory disease

Chronic or Systemic Conditions

  • Aging
  • Autoimmune disease
  • Cancer
  • Endocrine disease
  • Gastrointestinal disease
  • Heart disease
  • Infectious disease
  • Kidney disease
  • Medications
  • Nasal disease
  • Neurologic disease
  • Pain
  • Respiratory disease

Acute Conditions

  • Dehydration
  • Fever
  • Gastroenteritis
  • Medications
  • Nasal disease
  • Nausea
  • Pain
  • Post-operative ileus
  • Post-surgery
  • Psychological (change in diet, routine, environment)

Acute Conditions

  • Dehydration
  • Fever
  • Gastroenteritis
  • Medications
  • Nasal disease
  • Nausea
  • Pain
  • Post-operative ileus
  • Post-surgery
  • Psychological (change in diet, routine, environment)

Consequences of Inappetence

When dogs do not eat over a period of time, they experience weight loss and muscle wasting. Owners can be distressed by these effects, and often perceive their dog’s quality of life to be poor. Weight loss is an obvious result of a decreased appetite and when nutrition is inadequate, dogs can actually lose disproportionally more muscle as well.

Consequences of a long-term catabolic state may include:1,2,3

  • Decreased survival
  • Decreased musculoskeletal strength
  • Delayed wound healing
  • Decreased immune response
About dog inappetence: what causes loss of appetite in dogs?

1Ettinger SJ, Feldman EC. Textbook of Veterinary Internal Medicine. Vol 1. 7th ed. St. Louis, MO: Saunders Elsevier; 2010.
2Lui DT, Brown DC, Silverstein DC. Early nutritional support is associated with decreased length of hospitalization in dogs with septic peritonitis: a retrospective study of 45 cases (2000-2009). J Vet Emerg Crit Care (San Antonio). 2012;22(4):453-459.
3Satyaraj E. Emerging paradigms in immunonutrition. Top Companion Anim Med. 2011 Feb; 26(1):25-32.

Mechanisms for control of food intake in dogs

Appetite Regulation

The regulation of appetite involves the coordination of many signals from the brain (mainly the hypothalamus), peripheral tissues (such as adipose tissue) and endocrine system (such as ghrelin, leptin and insulin).

Ghrelin (the “hunger hormone”) binds to specific cell receptors and affects the signaling in the hypothalamus to cause the feeling of hunger, which in turn leads to food intake. Ghrelin also impacts energy, homeostasis and metabolism, and is essential for survival.

Appetite Treatment

Decreased appetite can be a symptom from an underlying chronic disease or acute condition. In the past, with no FDA-approved drugs to stimulate appetite, veterinarians have had limited therapeutic options.

With ENTYCE® (capromorelin oral solution), veterinarians have an FDA-approved appetite stimulant for dogs. ENTYCE was developed specifically to stimulate appetite and because its mechanism of action mimics ghrelin, it signifies a first-in-class treatment option.

IMPORTANT SAFETY INFORMATION: ENTYCE® (capromorelin oral solution) is for use in dogs only. Do not use in breeding, pregnant or lactating dogs. Use with caution in dogs with hepatic dysfunction or renal insufficiency. Adverse reactions in dogs may include diarrhea, vomiting, polydipsia, and hypersalivation. Should not be used in dogs that have a hypersensitivity to capromorelin. Please see the full Prescribing Information for more detail.

Other therapeutics from Aratana

Nocita® (bupivacaine liposome injectable suspension)
NOCITA® (bupivacaine liposome injectable suspension) is the only long-acting local anesthetic that controls post-op pain with one dose at the source for up to 72 hours following canine cranial cruciate ligament surgery or feline onychectomy to help patients recover comfortably. 

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DOG INDICATION: For single-dose infiltration into the surgical site to provide local post-operative analgesia for cranial cruciate ligament surgery in dogs.

IMPORTANT SAFETY INFORMATION: NOCITA® (bupivacaine liposome injectable suspension) is for local infiltration injection in dogs only. Do not use in dogs younger than 5 months of age, that are pregnant, lactating or intended for breeding. Do not administer by intravenous or intra-arterial injection. Adverse reactions in dogs may include discharge from incision, incisional inflammation and vomiting. Avoid concurrent use with bupivacaine HCl, lidocaine or other amide local anesthetics. Please see the full Prescribing Information for more detail.

CAT INDICATION: For use as a peripheral nerve block to provide regional post-operative analgesia following onychectomy in cats.

IMPORTANT SAFETY INFORMATION: NOCITA® (bupivacaine liposome injectable suspension) is for use as a peripheral nerve block in cats only. Do not use in cats younger than 5 months of age, that are pregnant, lactating, or intended for breeding. Do not administer by intravenous or intra-arterial injection. Adverse reactions in cats may include elevated body temperature, infection or chewing/licking at the surgical site. Avoid concurrent use with bupivacaine HCl, lidocaine or other amide local anesthetics. Please see the full Prescribing Information for more detail.