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Irritable Bowel Syndrome (IBS) in Dogs

Date Published: 03/21/2005
Date Reviewed/Revised: 03/02/2021
Photo courtesy of Depositphotos

The signs of inflammation in the colon (also called the large intestine) are the same regardless of cause: a gooey, mucous diarrhea, straining to pass stool, cramping, and sometimes a surprise urgency to "go." These symptoms can be acute, as is common with a short-term stress like boarding, returning from boarding, or diet change, or they can be chronic as with whipworm infection or inflammatory bowel disease.

Many people get confused between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). IBD is a physical disease where the intestinal lining is infiltrated by inflammatory cells. The delicate intestinal lining becomes thickened and it alters the absorption of nutrients. The infiltration can be seen under the microscope, which is how the diagnosis is confirmed. IBD is a completely different disease from IBS.

IBS is a psychosomatic disease. It is the activity of the mind that causes the symptoms. Most people have had some kind of experience where stress has produced intestinal distress, be it cramping, nausea, diarrhea or all of the above. Chronic anxiety can similarly result in chronic diarrhea. This is basically what IBS is all about. Intestinal biopsy results are normal because there is nothing directly wrong with the large intestine. The process is the same whether the patient is human or not. Intestinal biopsy results are normal because there is nothing physically wrong with the large intestine.

Large intestinal diarrhea in veterinary patients can have many causes and IBS is afoot in about 10-15% of cases. It is important to rule out physical causes before blaming psychological reasons and it has been recommended not to use the term "IBS" until a thorough work up has ruled out physical diseases. After a thorough work up has turned up normal results and we are still left with an anxious patient with recurring diarrhea, then it is appropriate to diagnose IBS and proceed accordingly. It should be noted that fresh blood in diarrhea is common with large intestinal diarrheas, but not so much with the large intestinal diarrhea of IBS. Fresh blood in the diarrhea is a sign that there is a physical cause and not a psychosomatic cause. Knowing this can help direct the medical approach.

Treatment of ILBS

The obvious approach is to address the anxiety. The source of emotional stress may not be obvious but general anti-anxiety medications such as amitriptyline, clomipramine, or fluoxetine may be of use, particularly if the anxiety source is not clear or cannot be removed. Some patients will respond to supplements as listed below. It is important to imagine the pet’s world from his perspective. The pet does not speak English and must infer what is going on from events he witnesses directly. Inconsistent scheduling, moving to a new home, noisy construction nearby, or even weather changes can be confusing for an animal.

More commonly, however, IBS is addressed through the GI tract rather than the psyche. Increasing dietary fiber is helpful to many IBS patients as fiber has been found to help normalize the spasms of the large intestinal muscles, and many therapeutic high-fiber diets are sold through veterinary hospitals. If your pet finds these unpalatable, ask your veterinarian about how to add wheat bran or a commercial fiber supplement to a diet your pet prefers. Several commercial dog foods contain calming supplements. Using one of these with a fiber supplement might cover both the fiber angle as well as the anxiety.

For many patients, cage rest or tranquilizers allow for enough rest to control symptoms. Antispasmodics or general anti-diarrhea medications such as loperamide, azulfidine, chlordiazepoxide, or metronidazole can be used on an as needed basis to control signs. Typically one to two weeks of treatment is needed.

A number of supplements have recently been marketed to address anxiety, not to mention pheromone products. These are not as strong as prescription drugs but are available over the counter for those who wish to try them.

  • Alpha Casozepine is a milk protein with natural calming properties. It is available as an oral supplement for pets or in calming pet foods. Talk to your veterinarian about the foods.

  • L-Theanine is a derivative from green tea and is available in capsules as well as flavored chews (Anxitane®, Solliquin®, Composure®).

  • Adaptil Defuser and Collars: Dog Appeasement Pheromone or D.A.P. is naturally secreted by mother dogs to communicate safety and security to her litter of puppies. This pheromone has been synthesized and is available as a room spray, plug in wall defuser, and as an impregnated collar that the dog can wear. This pheromone gives the anxious dog a message in their own language that there is nothing to be anxious about.

  • Cannabinoids (CBD) supplements are obviously of controversy and are not currently legal except as hemp products, which may be appropriate. CBD is commonly marketed for pets but at this time none of the recent legalization efforts have included pet products and quality control is lacking at this time.

Consult your veterinarian if you wish to pursue one of these therapies but keep in mind that IBS is not diagnosed until a medical work up for physical causes of large bowel diarrhea has come up empty.