In a rather unique case of veterinary drug repositioning, a research team have found that a liquid form of sildenafil tablets could be a long-awaited solution for a rare, potentially fatal eating disorder in dogs.
A team based at the College of Veterinary Medicine at Washington State University have found a potential treatment to relieve the symptoms of megaoesophagus in the drug most commonly known as Viagra and how its active ingredient works.
Megaesophagus is a rare disorder in dogs that causes the gullet of a dog to swell up and stops its ability to move effectively, causing food to get stuck in the lower part of the oesophagus, which can cause regurgitation, food entering the lungs and potential death through aspiration pneumonia.
The condition currently has no cure and according to Dr Jillian Haines, the veterinarian who was co-lead on the study, most dogs that have it die within eight months, either as a direct result or are put down due to poor quality of life.
It has, up until this point, believed to not have a cure or effective treatment; the only intervention that has worked up until this point has been the use of a Bailey chair, which keeps them upright and allows gravity to aid in digestion and help food get to the stomach and help the oesophagus.
The WSU study tested the use of a liquid sildenafil mixture that would, much like its use in heart treatments and erectile dysfunction, relax the muscles in the gullet, allowing it to open and for food to easily and safely pass through, reducing regurgitation.
It works for between 20 minutes to an hour, which is enough for the average mealtime as the lower oesophagal sphincter only needs to be open whilst the dog is having a meal.
The study was relatively small due to the rarity of the condition, focusing on ten dogs who were given either sildenafil or a placebo for two weeks at a time before having a week of neither and finally swapping over for the last two weeks.
Their owners would then report any times that they regurgitated food, their weight and any side effects.
Nine of the ten dogs had reduced the number of times they regurgitated food during the time they were taking the sildenafil according to their owners, to the point that Dr Haines reported that the owners immediately figured out when they were not using the placebo because it was working.
She further noted that several of the dogs were prescribed the drug regularly after the study, and they are still using it as of the time the study was published, and also stated that other vets have been asking about the drug.
Further work, particularly regarding its effectiveness on a wider scale and any side effects will need to be undertaken before it can be prescribed on a wider scale, but the team hopes that it will receive support and be widely used as a treatment for a painful, potentially lethal condition previously deemed untreatable.