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What are the side effects of Simparica?

 by ben on 03 Jun 2019 |
31 Comment(s)

We all want to protect our pets from fleas, ticks and the diseases they carry, but some treatments can come with nasty side effects.

Every good pet parent wants to keep fleas off his dog, but many worries about the side effects that can accompany various flea and tick treatments. Fortunately for conscientious dog moms and dads, Simparica offers a once-a-month chewable treatment that is FDA-approved and safe for Fido, taking the guesswork out of fighting fleas and ticks.

Like other oral treatments, Simparicaworks by entering a dog’s bloodstream immediately after ingestion. When fleas or ticks bite, they are exposed to its FDA-approved ingredient sarolaner, the insecticide, and acaricide that kills parasites fast. Sarolanerstarts fighting fleas within three hours and begins to kill ticks after 8 hours—including the lone star tick, black-legged tick, brown dog tick, American dog tick, and Gulf Coast tick. Because this ingredient works differently on invertebrates than mammals, however, Simparica for dogs has been proven safe during field trials.

Simparicaworks by impacting the nervous system of invertebrates such as fleas and ticks. The innovative formula disrupts gamma-aminobutyric acid (GABA) and glutamate receptors, which both play a role in nerve transmissions. GAGA-gated channels help to calm nerve transmissions, which sarolaner alters, creating an influx of nerve transmissions. At the same time, it opens glutamate-gated channels, which adds to the flood of nerve communications. The results are fatal for fleas and ticks but safe for mammals such as your dog.

Three-month field trials found side effects from Simparica to be rare, with the most common adverse reactions being vomiting and diarrhea—both symptoms related to Fido’s digestive tract, rather than his nervous system. In isolated cases, however, dogs displayed more serious reactions such as tremors, muscle twitching, and seizures. Simparica is available by prescription only, so discuss any history your dog has of seizure disorders with your veterinarian when determining the best flea and tick treatment for your pet.

In addition to killing fleas and several kinds of ticks, Simparicais effective in preventing and treating mange and ear mites. Thanks to its innovative formula, the treatment continues to work for 35 days, providing long-lasting relief from parasites and the diseases they carry. Simparica is available in different doses for dogs 2.8 pounds and over, but has not been evaluated for use in pregnant, breeding or nursing pets. Discuss Simparica chewable treats with your veterinarian when looking for a safe, effective way to arm your dog against biting parasites and the diseases they carry.


Cheryl Bell - Comment
Cheryl Bell31 May 2020Reply
Is it possible that Simparica could cause neurological issues with my dog. He was diagnosed with "Sundowners" . I have noticed that he hardly needs no meds for this neurological issue near the end of the month. I give my dogs Simparica at the beginning of each month. Just wondering?
Laura - Comment
Laura31 May 2020Reply
I say yes! My dog steadily went downhill after I gave her the first dose of simparica. After about 2.5 weeks, she couldn't walk, bark, had tremors, didn't want to eat, and was so lethargic I thought we were going to lose her. Her heartbeat was more of a vibration than a beat and the vet wanted her to see a cardiologist. The cardiologist found no heart condition that would cause this. After about a week, she started to improve. This is happening now and she is still nowhere near 100% but I am hopeful that she will eventually fully recover. She is only 6 and was so full of life and energy. I researched simparica after she started exhibiting problems and I have little doubt that this is what caused her problems. I am giving her supplements to support her heart and nerves and she's a little better each day. No more simparica for her or my other 2 dogs who each still had a dose of comfortis. No simparica for them either!
Nadia  - Comment
Nadia 14 Jul 2020Reply
I gave my dog his first dose today and 6 hours later he was throwing up and became frantic to get outside to eat grass. Although he didn’t continue throwing up and was fine otherwise, he was still outside 12 hours later eating grass. I’m switching back to the old stuff.
Erin Hall - Comment
Erin Hall25 Jul 2020Reply
Gave my dog Charlie Simparica yesterday now he is shaking and panting really bad. No appetite, not like Charlie. He seems dehydrated. I've tried Gatorade and Ginger ale but he only drank a little. What should I do?
Denise - Comment
Denise03 Aug 2020Reply
We gave Simparica two days ago and he's not had an appetite, he's eating grass, is drinking a lot of water and sleeping. How long do the side effects last? We wont be using this medicine ever again!
Judi - Comment
Judi05 Aug 2020Reply
Gave Simparica to my dog yesterday. Today he won’t eat, is sleeping all day, and when he is up he is panting heavily. I’m done with this drug!
Toni wallet - Comment
Toni wallet10 Aug 2020Reply
I gave my precious puppy this and 12 hours later
He is having profuse diarrhea, urinating constantly and he is supper agitated
My vet did not tell me anything about the side effects
Camella Johnson - Comment
Camella Johnson12 Aug 2020Reply
I am sure simparica caused a fatal seizure in my boxer. She passed away soon after taking this medication. I will never use this product again!!!!! I advise all pet owners to know the side effects. My veterinarian did not warn me of these and now my precious boxer is gone!!!!!
Wendy - Comment
Wendy16 Aug 2020Reply
I feel so sad for you Camelia. Thank you for giving information on what happened to your dog. Our new vet has recommended Simperica, but I won’t be giving it to my Collie.
John - Comment
John21 Aug 2020Reply
Gave my 28lb German Spitz her monthly prescibed dose of Simparica. Not long after ingesting the chewable she began to have tremors, but not full blown seizures. Tremors continued, on and off, for 2 hours. Took her to her Vet where I was told she had another tremor. They could either keep her there for observation or I could take her home to observe her. I took her home. She's been given this dosage for over a year. First time for this adverse reaction. 5 hours after the dose she's home resting. I'll continue to watch her.
Brooke - Comment
Brooke21 Aug 2020Reply
How long did these symptoms last? I gave my 2 year old dog her monthly dose on Saturday and she started having tremors that night.
Joey - Comment
Joey22 Aug 2020Reply
gave this to my dog three different times. This time he is having seizures. He will be laying then start shaking all over..Has tremors every 5 minutes for 2 hours now.
Martha Davenport - Comment
Martha Davenport03 Sep 2020Reply
Gave this to my dogs and now he sleeps all the time and tired and has symptoms now like droopy right side weakness can’t blink right eye and drooling like bell’s palsy
Tizzo  - Comment
Tizzo 03 Sep 2020Reply
This happened the same to my dog.. how si going now with your pet?
Charlene - Comment
Charlene03 Sep 2020Reply
I am up writing this 4 a.m. since our Lambchop is too restless to sleep! Never happened before. Gave Simparica yesterday and am suspect. Has odd agitated swallowing when not eating anything. He's a 1 1/2 y.o. Coton de Tulear.
Richelle - Comment
Richelle06 Sep 2020Reply
My vet prescribed my 16 week old puppy this drug because of a skin irritation. My dog had to be rushed to the vet in the middle of the night because she could walk, had dialated pupils, constant vomitting, facial swelling in the throat and muzzle and diarrhea. She is still in the vet since 3am. My vet never mentioned that puppies under 6months cannot be prescribed this medication. Still waiting to find out of she has progressed. Very dissapointed with my vet for not informing me of the risk this has on my dog.
Pat - Comment
Pat08 Sep 2020Reply
This drug has caused our dog to loose his footing and not eat. He looked like he was having spasms. Doing better now, 2 days later. No more Simparica for him.
John - Comment
John10 Sep 2020Reply
Our dog has not been given another dose. I will be speaking to vet to switch to something else. The reaction lasted less than 12 hours. She's been fine since. Doubtful our dog will be given Simparica again.
Dave - Comment
Dave18 Sep 2020Reply
we gave our dane Simperica Brown about a day or so ago and all the sudden my sweet girl is having seizures. Never had them ever and she's only 3 1/2 yrs old. Still waiting on the vet and waiting to talk to ASPCA poison control. Furious that this out there for pets. Vets at Petsmart should know better; changing vets
Kim Kelly  - Comment
Kim Kelly 27 Sep 2020Reply
My Irish setter is weak on her left side, left side of her face is drooping and she now carries her head with a tilt to the left. It has been 20 days since I gave her the prescribed dose of Simparica. The issues started within 24 hours of the dose and continue. This was the first time she was given this drug and will be the last. I feel like this drug was pushed by my vet tech and veterinarian. My dog weighs 60 pounds and was given a dose for dogs up to 88 pounds. I feel like it was a massive overdose. She falls when she runs and when going up and down stairs. She’s not the carefree setter she was prior to this medication.
Nathalie - Comment
Nathalie04 Oct 2020Reply
This is terrible. We gave our 3.5 month old Aussie pup a dose of Simparica today (vet's prescription), and I did not see the warnings about giving it to dogs under 6 months. She had what seemed like a seizure 6 hours after ingesting this product--she was lying in her crate, she peed while lying down, and she vomited, then began rocking back and forth--and now I am terrified for her (it's Saturday, nearly midnight, so tomorrow is Sunday and everything is closed). I've spoken to emergency vets and they say they are booked solid and that I need to just monitor her through the night. She's wobbly on her feet and seems lopsided, although her eyes look ok; she is really lethargic and barely lifting her head. I'm just so angry that the vet prescribed this and I am mad at myself for not researching it.
alden - Comment
alden09 Oct 2020Reply
My Labradoodle had extreme diarrhea last night. My wife and I didn't understand why. After realizing that the only thing that we did differently was to give him his first dose of Simperica, my wife began research and came across this conversation. Thankfully there have been no other side effects. Thanks all for sharing your experiences. It really helped us to put this diarrhea condition in perspective.
Melanie  - Comment
Melanie 09 Oct 2020Reply
Can I ask how long the diarrhea lasted? I gave my 6 month old pup this medication on Monday morning and he’s had diarrhea since yesterday (Tuesday) afternoon.
Johe - Comment
Johe09 Oct 2020Reply
I gave our 9 month old mimi labradoodle her first dose of Simparica two days ago. All went well until this morning. She had terrible watery diarrhea and is not interested in eating. I too would like to know how long this symptom lasted in other dogs who experienced the same issue. I notified my vet and Zoetis, the company that makes this drug. The representative for the company says the half life is 16 days. I am worried!
Alaina - Comment
Alaina09 Oct 2020Reply
I gave my 5 lb maltipoo a new flea treatment called Simparica and two weeks later she started having seizures. They have increased and worsened over the last 3 months. I’ve spent over $3,000 on vet bills for at least four visits to the ER and follow up lab work including X-rays. The vet has not been able to diagnose a cause. I even told them about the Simparica which they don’t respond to.
They put her on Phenobarbital to stop the seizures but cause her to be very wobbly and she’s been throwing up over the last two days and stopped eating today. How can I help of the manufacturer’s of Simparica responsible for causing so many dogs to experience these adverse and most likely permanent side effects.
Rachael  - Comment
Rachael 10 Oct 2020Reply
Gave my dogs simparica and they both have lost their appetite! The king cavalier bichon mix seems to be ok just not eating much if at all. The Maltese mix is lethargic and won’t jump on bed or couch. I don’t know what to do to get this out of their system?? Please advise!
Kathy Coyne - Comment
Kathy Coyne18 Oct 2020Reply
just gave my one year old dauchund her first dose of simparica My vet didnt tell me
Dave - Comment
Dave21 Oct 2020Reply
We gave our Yorkie this and she went into seizures later in the day...what if any thing can be done
Jayne - Comment
Jayne27 Oct 2020Reply
My beautiful boxer lost his appetite after just one dose of Simparica. The following day he would not even drink water.
After a vet visit, he was put on a good gastro food and probiotics and he seems to be back to his old self. In his case it was all a digestion side effect but a nasty one also with diarrhea.
Kate - Comment
Kate14 Nov 2020Reply
I recently switched my 3.5 year old German Shepard to simparica and about 2 weeks after his first dose he had two seizures in one night and has NEVER had them before. We rushed him to the emergency vet and they put him on keppra to stop the seizures. But im 99% sure the simparica is what caused it. And im so mad that my vet didn't inform me of the side effects and im so mad I didn't research it myself.
Andrea Dansby  - Comment
Andrea Dansby 15 Nov 2020Reply
The vet just gave our 16lb shorkie this on Tuesday and he still has the tremors really bad and very lethargic, I’m very worried and concerned. Anything I can do for him? Thank you
charles lews - Comment
charles lews18 Nov 2020Reply
We gave our 13 yr old lab mix this medicine as our doctor doesn't carry trifexis anymore. Eight hours later and she has terrible diarrhea and vomiting, now she is not eating. She spent 4 nights at the University of Auburn emergency room and vet clinic. I went and picked her up today and all she does is lay around and drink water, turns her nose up at anything food related. I am so beyond mad, what can I do to get this out of her system and better yet what can we do to get this product off the market.
Candice - Comment
Candice19 Nov 2020Reply
This Tuesday the 17th I had given my dog simparica trio for 27lbs dose. That evening after giving it to him he has puked various times. Will not eat or drink. I've had to syringe water in his mouth. He is acting very skittish/scared like behavior, wants to just lay down. Haven't noticed any other symptoms to him besides the puking, not eating and skittish. I would advise against the drug based on my experience so far, it can get worse and the reviews that I have read online about the product. I wish I read about this particular product before giving it to my dog because now I'm worried he may get more symptoms. Will be talking to the vet inregards to his side effects.
Linda - Comment
Linda20 Nov 2020Reply
I have my 14 week old pup simparica (vet recommended) 2 days ago. Poor baby has had vomiting and diarrhoea ever since. She is lethargic and doesn’t want to eat. I am keeping a close eye on her and will take her to the vet if she hasn’t improved by tonight. This crap is poison! Never again are my dogs getting oral medication for fleas & ticks. This stuff should be banned.
Linda - Comment
Linda27 Nov 2020Reply
Gave my 12 year old labradoodle simpatico just before going to my son’s for T-Day dinner. Got home 4 hours later and my dog fell down three times and is now seizing ... mainly her head . Hard fast shaking and terrified eyes. She has been the healthiest, happiest dog. Seizures are going on two hours....☹️
Linda L McPherson - Comment
Linda L McPherson01 Dec 2020Reply
Follow up: my Labradoodle visited the ER on T-Day for 2 hrs. Seizures continue and it’s Monday. Dr said either Simparica (best case scenario), GOLPP or brain tumor. Good appetite but seizures cause her to fall...Dr says: leash walks, keep kenneled or confined in small room, no playing for 7-10 days and see what happens ???? If she recovers, cause is the Simparica. Not known if there be permanent after-effects.
Karen - Comment
Karen01 Dec 2020Reply
Omg I’m feeling sick seeing all these bad comments. Is there any good outcomes from this tablet? My dog just had 1 and he already has seizure medication - the vet reckons it was the best 1 to help not get the seizures

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