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Rebecca, Dog Veterinarian
Category: Dog Veterinary
Satisfied Customers: 15134
Experience:  More than 30 years of companion animal practice.
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I put Sentry Pro flea prevention on my dog last night and

Customer Question

I put Sentry Pro flea prevention on my dog last night and she has had a bad reaction. Restlessness, panting, heart racing and muscle spasms in her rear legs. She whined and could not settle down all night.
I went to the store and bought Benadryl and Dawn dishwashing liquid to bathe her. She seems to be a little better but is still restless and still has the spasms.
What should I do at this point?
Submitted: 1 year ago.
Category: Dog Veterinary
Expert:  Rebecca replied 1 year ago.


I am sorry to hear you are worried about Jessie reacting to this flea medication. My name is Rebecca. I am a veterinarian and will do my best to help.

You did well to bathe her, to get as much off as you can. How much does she weigh? One Benedryl would be good for a 25 pound dog, and can be repeated every 8 hours.

Is she eating and drinking? If you check her gums, are they pink in color?

Give me a moment to look up the active ingredients in Sentry Pro; I will be right back.

Expert:  Rebecca replied 1 year ago.

The Cyphenothrin in this product is a pyrethrin, which can cause muscle tremors. There is no antidote, you either wait for it to wear off, or give a muscle relaxant such as methocarbamol (prescription medication) to control the tremors/spasms. Do not give a dog the over the counter muscle relaxant called Flexeril; it is not safe in dogs.

Expert:  Rebecca replied 1 year ago.

The other ingredient, pyriproxyfen, is considered to be pretty safe in dogs. If she is reacting, it is probably the cyphenothrin.

I recommend not using pyrethrin based flea control (Cyphenothrin is a synthetic pyrethrin) because it has side effects and is not as effective as the newer flea products. I like the Seresto collar (costly, but lasts 8 months and so safe a dog can eat the collar and be OK), Frontline (not systemically absorbed), Nexgard and Bravecto.

Let me know how she is doing and what other questions you have. Was this helpful?

Expert:  Rebecca replied 1 year ago.

I hope you were able to see what I wrote; I have not heard from you! If I can answer anything or research anything more for you, please let me know, and and how Jessie is doing. Kindly consider rating my answer if this was helpful.