If your dog was diagnosed with paralysis of the voice box, you may be wondering whether the drug doxepin for dog laryngeal paralysis may help. The answer to this question is that the effectiveness of this drug ultimately depends on several factors. To better understand the role of doxepin in dogs suffering from laryngeal paralysis, it helps to firstly better understand what happens when a dog suffers from paralysis of the larynx and how the drug doxepin works. Following is some information about doxepin for dogs with laryngeal paralysis.
Paralysis of the Larynx
As the term implies, laryngeal paralysis is a paralysis that affects the dog's larynx, better known as voice box. In a normal, healthy dog, the larynx has good muscle tone allowing the dog to eat, breath and vocalize with little effort.
When a dog develops laryngeal paralysis, the muscle tone is lost. The area becomes weakened and flaccid due to an interruption of nerve impulses from the recurrent laryngeal nerve which supplies the muscles of the larynx.
The laryngeal muscles are therefore no longer able to respond to nerve impulses. Affected dogs therefore develop trouble swallowing, breathing and barking. Dog owners may notice labored breathing, coughing and changes in the way the dog barks.
Because the dog's larynx controls the process of swallowing water and foods, and prevents aspiration in the lungs, a dog with laryngeal paralysis is prone to choking on water and food and is at risk for developing aspiration pneumonia.
Laryngeal paralysis in dogs can be congenital or acquired. Dogs with the congenital form typically show signs early, usually before they reach one year old, while dogs with the acquired form tend to develop signs when they are much older. Large breed dogs are more often affected.
Conventional treatment is a surgical procedure known as arytenoid lateralization. or more commonly, "tieback surgery "where the airway is kept open courtesy of several strategically placed permanent sutures.
Ruling out Other Problems
Before considering treatment options such as doxepin for dog laryngeal paralysis it is essential to rule out other medical disorders that may be causing the symptoms noticed. While in many cases, acquired laryngeal paralysis is idiopathic, a medical term used to depict a condition of unknown cause, in some cases, an actual culprit may be found.
Conditions that may contribute to laryngeal paralysis include a mass in the neck that compresses the laryngeal recurrent nerves, trauma to the nerve from a fight with another dog or neck surgery, or perhaps some sort of disease affecting the laryngeal recurrent nerve such as hypothyroidism or a disease of muscle tissue (myopathy) involving the muscle of the larynx, explains Dr. Eric Monnet, a veterinarian specializing in surgery.
Your veterinarian may therefore recommend several tests to rule out some medical conditions that may be contributing to the problem. Tests may include bloodwork, (including thyroid panel), x-rays laryngeal examination under general anesthesia and sometimes an ultrasound examination of the vocal chords.
Doxepin for Dog Laryngeal Paralysis
Doxepin (trade name Sinequan) is a human tricyclic antidepressant that is used to treat problems such as depression and anxiety. In dogs, there are really yet no controlled studies on the use of doxepin for dog laryngeal paralysis; however, anecdotal reports look promising.
According to veterinarian Dr. Fiona, the benefits of doxepin for dog laryngeal paralysis were just discovered by chance by a vet who put a dog on this drug for other reasons and casually stumbled on remarkable improvement. Several others vets gave it a try and the results are encouraging after all.
Dr. Karing shares the post by the vet "I just tried doxepin today in my own dog... the response has been practically miraculous. My >11 yr old Flat-Coat-ish dog went from being rarely able to breath without wheezing and panting with both inspiratory and expiratory noises to even being able to walk outside for (very) short periods (in the 100F heat) without panting. Last night and this am he had no appetite, he ate with the most interest I've seen from him in months just a few minutes ago. Color me very very happy!"
It is not entirely clear why this drug helps, but there are likely chances that doxepin somehow works for neuropathic pain. Because doxepin has marked antihistaminic effects, it can cause a dry mouth as a side effect.
However, it's important to precise that the use of doxepin for dog laryngeal paralysis appear to be for the most part beneficial to dogs with lighter forms of this condition (partial paralysis). If there is total paralysis, there is likely no medication that can help, further points out Dr. Fiona.
"When stridor is caused by total laryngeal paralysis, I do not know if doxepin/tricyclics would work. Then, it seems that surgery is the only effective option. However, when there is laryngeal spasm causing stridor and cough and gagging, then Doxepin can be very helpful! "~Dr. Fiona, veterinarian
Potential Dog Candidates
As mentioned, the use of doxepin for dog laryngeal paralysis appears to be for the most part suitable for dogs suffering from partial paralysis, medically known as paresis. Often, use of this drug is also suggested when dogs are too old for surgery, when dog owners do not have the finances for the surgery or when the risks for complications from the surgery outweigh the benefits. Advanced cases are in most cases not suitable.
Veterinarians may suggest the use of doxepin alone, or possibly along with acupuncture, and see how the dog responds. Along with giving doxepin, it helps if dog owners can keep their affected dogs from gaining too much weight or exposing them to extreme temperatures, both factors that have the potential for exacerbating laryngeal paralysis in dogs, explains veterinarian Dr. Karing.
If the drug appears beneficial, it's important for dog owners to keep in mind that dogs with laryngeal paralysis are at risk for heat stroke, aspiration pneumonia and death. If results are not optimistic, then surgery is usually recommended.
"Overall success with the surgical procedure is reported to be 80-100%. Aspiration pneumonia can potentially be a serious consequence of the disease or following surgery. This risk seems to be present life-long with this disease."~Dr. Don R. Waldron board-certified veterinary surgeon.
An Upcoming Study
As seen, the use of doxepin in dogs suffering from partial laryngeal paralysis may be worth a try if the vet recommends it.
Dog owners considering using doxepin for dog laryngeal problems, may be interested in seeing the results of an ongoing study that is supposed to be closing soon in July 2019. The study has been observing the effect of doxepin when administered for one month to Labrador retrievers suffering from non-critical laryngeal paralysis.
The result of this study will provide relevant data about the use of doxepin in dogs with laryngeal paralysis. Hopefully, the results will be promising enough so that its use would be considered for dogs who are potential candidates.
For further reading:
- How a dog's vagus nerve influences laryngeal paralysis
- Laryngeal paralysis and hypothyroidism
- How long can a dog live with laryngeal paralysis without surgery
- Aspiration pneumonia after tieback surgery
- DVM360: Laryngeal paralysis (Proceedings)
- DVM360: Laryngeal paralysis in dogs and cats (Proceedings)
- Veterinary Information Network: Prospective randomized clinical trial of doxepin in canine laryngeal paralysis