New Noise Aversion Drug Could Be Dangerous

Since we just celebrated our nation's independence with lots of fireworks and we are now entering summer thunderstorm season where we live, I have had plenty of questions from clients and subscribers asking about the new "Noise Aversion Drug", Sileo. This drug is actually dexmedetomidine, which is a sedative and pain relief medication used for surgical, dental, and clinical procedures. I have used dexmedetomidine quite often for patients in my hospital. Normally, all goes well and procedures go smoothly. However, we routinely monitor EKG, blood pressure, oxygen saturation, and body temperature when animals are under sedation with this drug. We commonly see decreased heart rate, decreased blood pressure, decreased body temperature, and sometimes heart arrhythmias. This does not cause great concern because we have the animals in a controlled situation where we can give intravenous fluids, oxygen, warming support, and reversal agents to bring them back out of sedation.

According to package labeling for dexmedetomidine, contraindications for use of the drug for sedation include: Do not use DEXDOMITOR in dogs or cats with cardiovascular disease, respiratory disorders, liver or kidney diseases, or in conditions of shock, severe debilitation, or stress due to extreme heat, cold or fatigue. As with all alpha2 -adrenoceptor agonists, the potential for isolated cases of hypersensitivity, including paradoxical response (excitation), exists. (Which means your pet may get more agitated instead of sedated.)

My concern with this new oral gel administration (in a "dial-a-dose" syringe) is the potential for overdosing. Granted, the drug is not as well absorbed when given on mucous membranes (the gums) as it is when we administer an intravenous or intramuscular injection, but what happens if a well meaning owner gives more than the prescribed dose? Will the pet become sedated, have heart arrhythmias, low blood pressure, or collapse? Will this drug be used appropriately and not used for pets with underlying medical conditions? Product safety instructions include the following warnings:

Do not use SILEO in dogs with severe cardiovascular disease, respiratory, liver or kidney diseases, or in conditions of shock, severe debilitation, or stress due to extreme heat, cold or fatigue or in dogs hypersensitive to dexmedetomidine or to any of the excipients. SILEO should not be administered in the presence of preexisting hypotension, hypoxia, or bradycardia. Do not use in dogs sedated from previous dosing. SILEO has not been evaluated in dogs younger than 16 weeks of age or in dogs with dental or gingival disease that could have an effect on the absorption of SILEO. SILEO has not been evaluated for use in breeding, pregnant, or lactating dogs. Transient pale mucous membranes at the site of application may occur with SILEO use. Other uncommon adverse reactions included emesis (vomiting), drowsiness or sedation. Handle gel-dosing syringes with caution to avoid direct exposure to skin, eyes or mouth.

It should not be used in dogs that are stressed (noise phobic dogs are stressed at the first sound). And you can't touch it or get it in your mouth while applying it to your dog's mouth...

It has NOT BEEN EVALUATED IN DOGS WITH DENTAL OR GINGIVAL DISEASE. Based on the pets seen in my office, most would not qualify for use of the drug due to pre-existing dental or gingival disease. If inflamed gums increase absorption rate, overdose could easily occur.

This product was only tested in two clinical trials. One trial used 89 dogs and the other used 24 dogs (plus some control dogs that were not given the drug). Personally, I do not think a trial with 113 dogs proves this drug is safe in the hands of pet owners. So, for now, I am not recommending the use of the drug. I would exhaust all other possible natural treatment options before resorting to this drug. Some of them can be found here. If you have a truly noise phobic dog that is a danger to himself or others and you have exhausted all possibilities with training, desensitization, and natural therapies, have a discussion with your veterinarian about which chemical alternative might be best for your individual pet. Remember, there is no "one size fits all" therapy. Start working with your dogs as puppies to desensitize them to noises.

Of course, I am always the last one to jump on any new drug bandwagon. Manufacturers need to show me years of safety studies with thousands of animals. I'm not willing to use my own pets or my patients as the guinea pigs for drug companies. I could name a long list of drugs currently on the market that have killed and are killing our beloved pets, yet continue to be used by unsuspecting pet parents. Please err on the side of caution.

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