Trifexis vs. Comfortis: What are the differences?

Trifexis and Comfortis are both great choices for a dog owner who wants to prevent fleas.  They both share the same primary ingredient, Spinosad.  Spinosad is taken orally and found in many flea preventatives.  Both Trifexis and Comfortis are taken orally.

Once administered, either of these medications take about four hours to kick in.  They are best for killing a flea population that already exists on your dog, and really shouldn’t be used as a preventative.

trifexis vs comfortis

How Trifexis and Comfortis are


Both of these medications are Spinosad based flea controls.  They are given to a dog orally. They last for thirty days, so it is necessary to administer it to a dog once a month.  Once given to the dog, it takes between 30 minutes and 4 hours to kill the fleas.

Comfortis and Trifexis are given orally and are beef flavored.  Neither of them provide any sort of protection from ticks, which depending upon where you live can be an even bigger problem than flees.


Trifexis vs. Comfortis Differences

Spinosad vs Frontline

Comfortis’ only active ingredient is the Spinosad, which means that it is just a beef flavored dosage of it.  It can’t kill flea larva or eggs.  If you aren’t looking for the added features of Trifexis below, Comfortis is the way to go.

Trifexis on the other hand utilizes Milbemycin Oximne, which helps protect the dog from a number of parasites.  These include:

  • Roundworms (adult)
  • Whipworms (adult)
  • Hookworms (adult)
  • Heart worms (juvenile)

So really the main differences between these two are going to be whether or not you want to treat these extra conditions with Trifexis, or if you are only looking for a flea killing solution.  If that is the case than Comfortis is going to be the better of the two options.

Trifexis is good for killing the flea eggs and larvae.  Add that to the other pests that it can kill/prevent, and it is a much more well rounded solution than Comfortis.


Spinosad Side Effects

Most of the time, your dog will experience minimal side effects from either Comfortis or Trifexis.  You should always consult a veterinarian before giving your dog any kind of medication.

Spinosad has been know to rarely cause the following:

  • Vomitting
  • Lethargy
  • Hives
  • Diarrhea
  • Drooling
  • Increase in Appetite

If your dog has ever experienced seizures, it is even more important to consult a vet before giving them either of these medications.  Nursing or pregnant dogs should NEVER be given either of these medications.

A good way to make sure that your dog has less of a reaction to the medicine is to make sure that it is administered to them on a full stomach.


Comparing Comfortis/Trifexis vs. Frontline.

The major differences in Comfortis and Trifexis when compared to Frontline are going to be the way that the medications are applied.  Frontline is applied to the back area of the dog, and is administered in liquid form.

Frontline is more of a preventative solution, whereas Spinosad based insecticides are more of a solution for a infestation that is currently happening.