How to give your dog Trifexis® (spinosad + milbemycin oxime)

Trifexis dosing information

You should administer one tablet once every month to provide year-round protection for dogs and puppies 8 weeks and older and 5 pounds or greater. The color-coded chart below matches the packaging to show how much of each active ingredient is in a tablet for the corresponding weight range.

Trifexis dosing chart

Administering Trifexis to your dog

Your veterinarian should test your dog for heartworm infection before administering Trifexis.

Trifexis is a flavored, chewable tablet that you can offer to your dog as if a treat. But it doesn't have to be chewed—you can give it to your dog like any other tablet medication. For maximum effectiveness, give your dog Trifexis with food. To ensure heartworm prevention, observe your dog for one hour after administration. If vomiting occurs within an hour after administration, redose with another full dose. Puppies less than 14 weeks of age may experience a higher rate of vomiting.

If you miss a dose, immediately administer Trifexis with food and resume monthly dosing. This will minimize the opportunity for heartworm infection. Also, continuing normal monthly dosing will help allow you to gain control of any flea infestation or intestinal parasite infection that might have affected your dog. 

The Companion Animal Parasite Council (CAPC), an independent group established to create parasite-control guidelines, recommends treating dogs year-round with a broad-spectrum parasite control.1 However, if you do not give your dog Trifexis year-round, then the treatment schedule should begin within one month of the first exposure to mosquitoes and should continue until three months after the last exposure to mosquitoes.