Get to Know Trifexis® (spinosad + milbemycin oxime)

Trifexis provides powerful, reliable protection against fleas, heartworm disease, roundworm, hookworm and whipworm, when used according to the label.

How Does Trifexis Work?

The primary target of action of spinosad, one of Trifexis’ active ingredients, results in flea paralysis and then eventually flea death.

Milbemycin oxime, the other active ingredient in Trifexis, prevents heartworm disease and protects against hookworm, roundworm, and whipworm.

Questions About Trifexis?

Have questions about Trifexis? Find answers to the most frequently asked questions below.


Trifexis prevents heartworm disease. Trifexis kills fleas and prevents flea infestations, and treats and controls adult hookworm, roundworm and whipworm infections in dogs and puppies 8 weeks and older and 5 pounds or more.

Important Safety Information

The use of ivermectin at higher than FDA-approved doses at the same time as Trifexis can result in serious side effects. Treatment with fewer than three monthly doses after the last exposure to mosquitoes may not provide complete heartworm prevention. Prior to administration of Trifexis, dogs should be tested for existing heartworm infection. Use with caution in breeding females. The safe use of Trifexis in breeding males has not been evaluated. Use with caution in dogs with pre-existing epilepsy. The most common adverse reactions reported are vomiting, decreased activity, itching, decreased appetite, and diarrhea. To ensure heartworm prevention, observe your dog for one hour after administration. If vomiting occurs within an hour of administration, redose with another full dose. Puppies less than 14 weeks of age may experience a higher rate of vomiting. For complete safety information, please see Trifexis product label or ask your veterinarian.

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Trifexis LogoProtect your dog all month long from fleas, heartworm disease and intestinal parasites with Trifexis.

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