Can I Use Frontline And Seresto At The Same Time? The Enlightening Answer!

There’s nothing worse than a flea-infested dog (and home).

When you’ve finally had enough and decide to go full Rambo on the little bloodsuckers, you may go all out and wonder, “Can I use Frontline and Seresto at the same time on my dog?”

You really want to get rid of the problem once and for all after all, and a combination of a Seresto collar and Frontline Plus topical treatment seems like a fine way to do it.

However, before you pull out all the stops, you definitely want to make sure that it’s safe for your pup! While both of the products no doubt kill fleas and ticks alike, no dog owner wants their companion harmed in the process.

So, before you decide to embark on such a mission, here are a few things to check and consider:

Check The Product Information

Seresto Flea and Tick Collar for Dogs, 8-Month Flea and Tick Collar for Small Dogs, Up to 18 Pounds

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Keep your dog safe by checking the product information.

You’ll usually find the information you need on the box, label, or inserted leaflet.

It would help if you looked for specific information, like active ingredients and adverse drug interactions. Hurting your pet is the last thing you want to do while trying to spare them from flea and tick bites.

Active Ingredients

If you have both Frontline and Seresto on hand or perform some cursory research, you’ll find yourself one step closer to answering the question.

A quick look at each product’s active ingredients reveals a lot about the risks of using them simultaneously. For one, Frontline and Seresto use different active ingredients.

Frontline contains the active ingredients fipronil and (S)-methoprene, whereas Seresto employs Imidacloprid and flumethrin.

So, at the very least, you technically wouldn’t end up double-dosing your dogs by using Frontline and Seresto together. However, if your dog has a bad reaction to one of the medications, you may have difficulty figuring out which one caused the issue.

Adverse Drug Interactions

Mastiff scratching in garden

Even though Frontline and Seresto flea and tick collars utilize different compounds to kill and repel fleas, an adverse drug interaction could make the cure worse than the disease. The possibility of an adverse drug interaction between the two medications could exist.

However, thankfully, it appears that these two medicines do not interact at all.

Dr. Leah Hill states that “There should not be an interaction between Frontline and Seresto.”

This conclusion is supported by Ian Wright of The Veterinary Nurse, who concludes that Fipronil “is safe when used in combination with other parasiticides.” Likewise, Imidacloprid “has no significant drug interactions with other parasiticides.”

While it would seem safe to use Frontline and Seresto at the same time, do you want to risk it without talking to your vet first?

We suggest that you call the vet and ask what he thinks about combining the two medications for your specific dog.

Can you use Seresto and Frontline on your dog at the same time? Yes, but always check with your vet beforehand.

Ask Your Vet

Veterinary clinic with a French bulldog going consultation with the owner

Before you start playing doctor with the family pet, you should always ask your vet for help.

More than likely, your vet will inform you that the answer to “Can I use Frontline and Seresto at the same time?” is in the affirmative.

However, he or she will likely point out that using both medicines could prove redundant since each has proven effective on its own.

Additionally, both Frontline and Seresto come with their own individual sets of side effects. Although rare, these side effects require identification.

The combination of Frontline and Seresto would make it more challenging to identify whether one or the other medication, or the combo itself, has caused the side effect. In short, doubling up on Frontline and Seresto is low-risk/low-reward.

Observe Your Dog

You serve as the first responder for your dog. Should you go against the advice of this article and apply both Frontline and Seresto before speaking with your vet, keep an eye on your dog.

While you can expect some changes in your dog’s behavior any time you apply a parasiticide, seizures, vomiting, rapid breathing, and non-responsiveness mean a trip to the vet.

You ought to look out for other symptoms, too.

Poor balance, excessive thirst, loss of appetite, unusual stools, and sluggishness all indicate the requirement of further careful observance and a call to the vet if the symptoms increase in intensity or frequency.

When in doubt, hop into the car and get your beloved family member checked out at your local clinic.

Which is Better, Seresto Or Frontline?

Seresto Flea and Tick Collar for Dogs, 8-Month Flea and Tick Collar for Small Dogs, Up to 18 Pounds

Perhaps you’ve already decided not to risk overloading your dogs with two different medicines that each serve the same purpose.

In that case, you’ll have to decide on one of the other flea medications.

But, which is better, Seresto or Frontline?

Well, it depends on your particular needs regarding the price, speed of efficacy, and longevity of either product.


A quick search online reveals that Frontline costs about $35 for a three-month supply, whereas Seresto costs around $55 for a flea collar that lasts eight months. After performing some simple maths, that works out to almost $12 a month for Frontline and $7 a month for Seresto.

In short, you can save yourself nearly $60 a year if Seresto works well for your dogs.

Speed Of Efficacy

For some dog owners, immediate relief for their pet trumps the importance of a flea treatment’s price or longevity.

Academics have conducted a number of studies regarding the short-term efficacy of various flea collars and topical flea medicines. According to a study performed by vets T. Schnieder, S. Wolken, and Norbert Mencke, a difference does exist.

Although the study involved cats, the fleas used- Ctenocephalides felis or cat fleas- are the same ones that infest your dogs.

The study showed that Imidacloprid (Seresto) reduced the number of fleas by 61.1% within the first 6 hours.

Fipronil and (S)-methoprene (Frontline) only reduce fleas by 18.8% within the same time frame. But, by the 42-hour mark, both achieved 100% efficacy.

What should you do if you find that Frontline doesn’t work for your dog? Click here to read our extensive guide on 8 other great methods to prevent fleas on your pup!


The scholars noted above also found significant differences in the efficacy of each substance in the long term.

Imidacloprid (Seresto) maintained a 90.8% reduction in fleas until the 35th and final day of the trial.

Fipronil and (S)-methoprene (Frontline) only achieved a 57.8% reduction at the end of the study (See Table 3 of the above-linked study). Thus, Imidacloprid (Seresto) is a more long-lasting medicine.

In Conclusion

Indeed, there exist other important parameters for determining whether Frontline or Seresto represents better flea treatment.

If deciding by price, speed of efficacy, and longevity, Seresto seems to lead all three categories.

Then again, every dog is different, and you will likely have to employ a trial-and-error method if the first drug doesn’t work well for your dog.

Have you ever used Frontline and Seresto at the same time? Please post your personal anecdote in the comments section to better assist our readers.

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