Viagra is a possible treatment for dog eating disorder

New research shows the potential of sildenafil, a generic version of viagra, for treating dogs with a dangerous eating disorder known as megaesophagus.

The disorder is characterized by an enlargement of the esophagus, which makes it hard for dogs to get food into their stomachs. Left untreated, dogs often vomit their food back up and aspirate pieces of food into their lungs. When food is ingested in the lungs, it can cause an infection called aspiration pneumonia.    

“The literature tells us that many dogs with the disease die from aspiration pneumonia or are humanely euthanized due to poor quality of life within eight months of diagnosis,” said Dr. Jillian Haines, a veterinarian at Washington State University who co-led the study.

Sildenafil relaxes the dogs’ esophagus, allowing food to pass through and into the stomach. The only known side effect is rare gastrointestinal irritation, but at the dosages in the current study, there were no side effects. 

“If you look at the literature, there are no drugs we can use to manage megaesophagus. Sildenafil is the first to target these mechanisms and reduce regurgitation, which is big because that’s what ultimately kills these dogs,” said Haines. 

“It opens the lower esophageal sphincter for 20 minutes to an hour, which works really well for dogs because we only want that to open when they are eating.”

In the study, ten dogs with megaesophagus were given either a placebo or sildenafil for a two week period. Next, after one week without either treatment, the control and experimental groups were switched. 

The dog owners were asked to monitor regurgitations. None of the owners were told whether their dog was taking the placebo or sildenafil. 

Despite no significant difference showing between sildenafil and a placebo during a 30 minute videofluoroscopy, nine of the ten owners reported less vomiting when sildenafil was being administered. Unfortunately, the drug does not seem to work as well on severe cases of the disorder – possibly because it is harder to get the drug into the dog’s stomach.  

“Moderately affected dogs that were regurgitating frequently but not excessively seemed to see the most dramatic results,” Haines said. “I actually prescribed sildenafil to several of those patients after the study, and they are still using it today.”

The study is published in the American Journal of Veterinary Medicine.

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By Zach Fitzner, Earth.com Staff Writer