Simparica is a once-monthly tick and flea preventative that has been proven to kill the ectoparasites rapidly. It comes in a delicious chewable tablet form making it exceptionally easy to administer. Its rapid-acting effect is courtesy of its active ingredient, sarolaner, a systemic insecticide that is duly approved by the FDA in the management of such parasites. It can kill fleas within 3 hours after administration while its tick-killing activity starts within 8 hours. Its insecticidal and acaricidal activities last as long as 35 days without any change in its insecticidal effectiveness. This gives it superior monthly protection against several species of ticks that are known to infest man’s best friend as well as fleas that carry intestinal parasites. Specifically, it targets the Gulf Coast tick, the lone star tick, the American dog tick, the black-legged tick, and the brown dog tick. It is administered to dogs that are at least 6 months old or that weigh at least 2.8 pounds.

medication simparica for dogs


Currently, Simparica is indicated in the management of the following:

  • Control, prevention, and treatment of flea infestations 

Fleas may not be known for causing serious harm to dogs except for those that have flea allergy dermatitis, these ectoparasites can still cause significant damage especially when ingested by dogs. Fleas carry parasites that can be released into the dog’s gut causing intestinal parasitism. Simparica has been proven to kill fleas within the first 3 hours of administration. Its insecticidal effect can last up to 35 days without substantial loss in its clinical effectiveness. Within 2 weeks, Simparica can kill up to 95.6% of all adult fleas found in the home. Its 100% flea-killing effect for the home is achieved by day 60.

  • Control, prevention, and treatment of tick infestations 

Ticks present a more serious problem not only for dogs but for humans as well. These parasites can cause very serious diseases that can lead to death. In the United States, there are several species of ticks that are known to infest man’s best friend. While some are located in specific geographic locations, the Brown dog tick is found nationwide. This warrants Simparica treatment regardless of where the dog is located. Simparica can start killing Brown dog ticks, Black-legged or deer ticks, Lone Star ticks, Gulf Coast ticks, and American dog ticks in as fast as 8 hours of administration. Studies show it retains a minimum of 96.9% effectiveness against these ticks for up to 35 days.

  • Treatment of sarcoptic mange, ear mite infestations, and demodicosis 

While Simparica doesn’t put in its label these indications, scientific literature shows that its active ingredient, Sarolaner, can also be used in the management of infestations caused by Sarcoptes scabiei, Otodectes cynotis, and Demodex canis, the causative agents of mange, ear mite infestations, and red mange, otherwise known as demodectic mange, respectively.

Benefits of Simparica

The benefits of giving Simparica for your dog are as follows:

  • Provides peak protection that lasts 35 days without losing any of its acaricidal and insecticidal effects.
  • It starts to kills fleas in as short as 3 hours after administration.
  • It starts to kill ticks in as short as 8 hours after administration.
  • It can also help prevent and treat mange, ear mites, and demodectic mange.
  • Can be easily administered because of its liver-flavored formulation.

How Simparica Works

Simparica contains the active ingredient Sarolaner which functions to inhibit the action of receptors for GABA or gamma-aminobutyric acid and glutamate. There are two principal effects of such mechanism of action.

First, its inhibitory effects on GABA receptors facilitate the flooding of the neuronal bridges with electrical impulses leading to seizures and death for the organism. Gamma-aminobutyric acid is one of the most important neurotransmitters in the central nervous system. Its principal action is the reduction of excitability of neurons or the transmission of nerve impulses from one neuron to the next. Sarolaner prevents GABA from exerting its effects so that there is hyper-excitation of the neurons of the central nervous system. This leads to generalized seizures that result in the non-delivery of important substances for cerebral metabolism. In turn, this results in the death of the organism.

Second, its inhibition of the action of glutamate receptors especially those found in chloride channels lead to the influx of electrical impulses coming from other neurons in the organism’s central nervous system. It should be noted that glutamate is one of the most common excitatory neurotransmitter in the nervous system, which is the diametric opposite of GABA. However, there are also glutamate receptors that are inhibitory in nature and these are the ones that are found in voltage-gated chloride channels. These inhibitory glutamate receptors act like GABA receptors. Sarolaner acts on these inhibitory glutamate receptors to allow for the sudden and voluminous influx of electrical impulses from other neurons leading to seizures and death.

It is this combined seizure-inducing potential of GABA- and inhibitory glutamate-receptor inhibition that Simparica is able to kill both fleas and ticks with relative ease.

Potential Side Effects

In several studies, Simparica was observed to be generally safe with very few mild to moderate complaints associated with its administration. As a matter of fact, some of the side effects noted were in fact lower than those treated with other brands. The following manifestations were observed in dogs given with Simparica for 3 months.

  • Vomiting
  • Weakness or lethargy
  • Loose, watery, or soft stools
  • Loss of appetite

However, there were isolated cases where more serious side effects were reported. These included the following.

  • Tremors or muscle twitching
  • Inability to control bodily movements
  • Elevation of the dog’s third eyelid
  • Seizures

Things You Should Know about Simparica

Simparica is approved by the FDA for the rapid treatment of fleas and ticks especially those that are common in the United States. It is available in 6 different dosage strength classifications to correspond to the 6 different weight classifications of dogs. It is available only on prescription and, while it is generally safe, it should always be administered following the instructions of your vet. It is given once a month, preferably all-year round to provide your dog with the best protection possible.

What You Should Tell Your Vet before He Prescribes Simparica

Since Simparica has not been evaluated on lactating and pregnant dogs, its use on these types of dogs warrants a closer scrutiny and evaluation by your veterinarian. Additionally, if your dog is taking any medication, preventative, or supplement it is best to inform your vet about these substances prior to giving Simparica to your dog. 

How to Give Simparica to Your Dog

Simparica is administered to dogs that are at least 6 months old or weigh at least 2.8 pounds. The formulation is in chewable form so it can be given more like a treat. However, if your dog doesn’t want to take it, it can be broken down into bits and mixed with a little amount of dog food. When giving you dog Simparica, it is important to observe it for a couple of minutes just to make sure that your dog consumed the entire tablet; otherwise you may have to give another dose. Simparica is also available in 6 different strength formulations each corresponding to the weight categories of dogs. Here are the formulations.

  • One 5 mg tablet for dogs weighing 2.8 to 5.5 pounds
  • One 10 mg tablet for dogs weighing 5.6 to 11 pounds
  • One 20 mg tablet for dogs weighing 11.1 to 22 pounds
  • One 40 mg tablet for dogs weighing 22.1 to 44 pounds
  • One 80 mg tablet for dogs weighing 44.1 to 88 pounds
  • One 120 mg tablet for dogs weighing 88.1 to 132 pounds

For dogs that weigh more than 132 pounds, they can be given a combination of these chewable tablet formulations.

If the main concern is in the treatment and prevention of fleas, then Simparica can be given any time regardless of the season. The same is true with tick control and treatment. It is equally important to treat every single pet in the household to minimize reinfestations.

Related Post: Best Dog Treats

What to Do If You Miss a Dose

In instances where you missed giving Simparica to your dog, give it as soon as you recall then resume the usual monthly dosing but utilizing the day upon which you gave the last dose and not the original schedule.

What to Do in Case of Simparica Overdose

Should there be untoward reactions in your dog, it is advisable to seek the assistance of your veterinarian at once.

simparica for dogs

Some Drug Interactions

To date, there are no drug interactions whatsoever that have been clearly identified as associated with the use of Simparica.

Simparica is a tick and flea preventative that works as fast as 3 hours in killing fleas and 8 hours for ticks. It is a once-monthly dosing that has very few side effects, if any at all. However, while it does show 35-day effectiveness, there are certain products in the market that can do a lot better. Nevertheless, given that it is a relatively new product, only time will tell if it can dethrone the leading brand.


  1. Inhibitory glutamate receptor channels., NCBI Pub Med
  2. Sarolaner, PubChem
  3. Simparica, 1800PetMeds


Olivia Williams
Olivia is our head of content for, mum of one and a true animal lover. With 12 different types of animal in her family, it's never a dull moment. When she isn't walking the dogs, feeding the cats or playing with her pet Parrot Charlie, you will find her product researching and keeping the site freshly updated with the latest products for your pets!


Please enter your name here
Please enter your comment!