What is Trifexis?

What is Trifexis® (SPINOSAD + MILBEMYCIN OXIME), and what does it protect against?

Trifexis is a monthly, chewable tablet for dogs. Trifexis kills fleas and prevents flea infestations on dogs, treats and controls adult hookworm*, whipworm and roundworm infections, and prevents heartworm disease. Trifexis is for use in dogs and puppies 8 weeks of age or older and 5 pounds of body weight or greater. If you do not administer Trifexis monthly throughout the year, continue administering the medication for at least three months following the last exposure to mosquitoes.

*A. caninum

Learn more about Trifexis

What are some of the benefits of Trifexis?

  • Trifexis is an oral monthly product that rapidly kills fleas on dogs and is effective in preventing heartworm disease and treatment and control of adult hookworm (A. caninum), adult roundworm and adult whipworm infections in dogs and puppies 8 weeks of age or older and 5 pounds of body weight and greater.
  • Trifexis is approved by the FDA as safe and effective when used according to the label.
  • Spinosad, one of the active ingredients in Trifexis, began to kill fleas on dogs 30 minutes after administration with 100% effectiveness within 4 hours in a well-controlled laboratory study.
  • Trifexis continues to kill fleas for a full month after treatment.
  • Dogs with signs of flea allergy dermatitis showed improvement in erythema, papules, scaling, alopecia, dermatitis/pyodermatitis and pruritus (itching) as a direct result of eliminating the fleas.
  • Trifexis is available in five strengths. Each tablet is formulated to provide a minimum dosage of 13.5 mg/lb (30 mg/kg) spinosad and 0.2 mg/lb (0.5 mg/kg) milbemycin oxime according to body weight.

Trifexis Dosing Chart

Learn more about dosing

How well does Trifexis work?

  • In a well-controlled laboratory study, Trifexis was 100% effective against induced heartworm infections in dogs when administered for three consecutive monthly doses. 
  • In well-controlled laboratory studies, a single dose of Trifexis at labeled dose was effective in removing roundworms, whipworms and hookworms (A. caninum).
  • In a well-controlled laboratory study, spinosad alone began to kill fleas 30 minutes after administration and demonstrated 100% effectiveness within 4 hours.

Spinosad kills fleas on dogs before they can lay eggs. If a severe environmental infestation exists, fleas may persist for a period of time after dose administration due to the emergence of adult fleas from pupae already in the environment. In field studies conducted in households with existing flea infestations of varying severity, flea reductions of 98.0 to 99.8% were observed during the course of three monthly treatments with spinosad alone. Dogs with signs of flea allergy dermatitis showed improvement in erythema, papules, scaling, alopecia, dermatitis/pyodermatitis and pruritus (itching) as a direct result of eliminating the fleas.

What are the active ingredients in Trifexis chewable tablets?

Spinosad and milbemycin oxime are the two active ingredients in Trifexis.

What is the flavoring in Trifexis tablets?

The flavoring in Trifexis comes from artificial beef flavoring made from pork-based proteins and hydrolyzed soy.1

Is Trifexis FDA approved?

Yes, Trifexis is a prescription medicine approved by the Food and Drug Administration and should be obtained only through a licensed veterinarian with whom you have a proper veterinarian-client-patient relationship.

Is Trifexis safe?

View video transcript

[Dr. Jeff Werber:
Trifexis is a safe, effective monthly tablet that is available from your veterinarian by prescription only. It’s a combination of two active ingredients—spinosad and milbemycin oxime—that have both been approved for use in dogs for many years. In the United States alone, more than 50 million doses of Trifexis have been dispensed through more than 15,000 veterinary clinics like mine.* In fact, many veterinarians around the country have such confidence in the safety and efficacy of Trifexis, they prescribe it for their own dogs.

Trifexis has been shown to be safe for dogs and puppies of all breeds 8 weeks of age or older and weighing 5 pounds or more. This beef-flavored tablet is not only convenient, it’s a smart way to give your dog his monthly preventative. Unlike topicals applied to your dog’s skin, Trifexis can’t be washed off or rubbed onto furniture or clothing. So there’s no need to isolate your dog from children or other pets after treatment.

All products have some risk. It’s important to read the label and understand what the most common adverse reactions that are associated with the drug. If your dog has a reaction to Trifexis, or any drug, report it to the manufacturer or FDA using the phone numbers found on the label. Given as directed, Trifexis is a safe, effective and convenient way to help protect your dog from parasites. If your dog has been using Trifexis successfully, there is no reason to expect that should change.

Ask about Trifexis, the combination product that kills fleas and prevents infestations, prevents heartworm disease, and treats and controls hookworm, roundworm and whipworm infections. See the full product label for complete safety information.

Serious adverse reactions have been reported following concomitant extra-label use of ivermectin with spinosad alone, one of the components of Trifexis. 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 dogs with pre-existing epilepsy.

The most common adverse reactions reported are vomiting, depression/lethargy, pruritus, anorexia, diarrhea, trembling/shaking, ataxia, seizures, hypersalvation and skin reddening. To ensure heartworm prevention, observe your dog for one hour after administration. If vomiting occurs within an hour of administration, redose.

*Vet Insite Analytics. "Based on total canine combination parasiticide product data (flea, tick, heartworm)." Dec. 2015.]

Trifexis is approved by the FDA for use in dogs and puppies 8 weeks of age and older and 5 pounds of body weight or greater. To receive FDA approval, Trifexis was tested in hundreds of dogs and detailed clinical reports were submitted for intense review. Since the product launched, Trifexis has been prescribed by veterinarians to millions of dogs around the world.2 Adverse events are reported to the FDA, and concerns are thoroughly investigated.

You should discuss the use of Trifexis with your veterinarian prior to use if your dog has a history of epilepsy (seizures). Puppies less than 14 weeks of age may experience a higher rate of vomiting.

Get more information about the safety of Trifexis

Is it safe to give my breeding dogs Trifexis?

Ask your veterinarian about the use of Trifexis prior to use in breeding females. The safe use of Trifexis in male dogs intended for breeding has not been evaluated.

What side effects might occur with Trifexis?

As with all medicines, sometimes side effects may occur. In some cases, dogs vomited after receiving Trifexis. If vomiting occurs within an hour of administration, redose with another full dose. During field studies, no severe or prolonged vomiting occurred. Additional adverse reactions observed in the clinical studies were itching, decreased activity, diarrhea, inflammation of the skin, redness of the skin, decreased appetite and redness of the ear. All reactions were regarded as mild.

What is the most common adverse event with Trifexis?

The most common adverse reactions based on post-approval adverse drug event reporting are vomiting, depression/lethargy, pruritus, anorexia, trembling/shaking, atazia, seizures, hypersalivation and skin reddening.

Average Monthly Rate (%) of Dogs with Adverse Reactions in a US Field Study

2. n=176 dogs for Trifexis and n=176 for Active control

If spinosad kills fleas, how is it safe for my dog?

Trifexis has been demonstrated to be safe in healthy dogs when used according to label directions. Spinosad, one of its active ingredients, is produced by a bacterium first isolated from natural sources (a soil sample collected in the Caribbean).3 Spinosad demonstrates selective toxicity to the flea’s nervous system but has low toxicity to mammals and other nontarget organisms.4 However, as with all medications, sensitivities due to individual animal variation can occur, sometimes resulting in side effects. See the Trifexis label for complete safety information.

How quickly will Trifexis kill fleas?

In a laboratory study of spinosad alone, this active ingredient of Trifexis started to kill fleas within 30 minutes and killed 100% of the fleas on dogs within 4 hours. Trifexis kills fleas before they can lay eggs.

Learn more about fleas

Will Trifexis kill heartworms?

Trifexis prevents heartworm disease in dogs by killing certain stages that develop after an infected mosquito bites a dog. As with other heartworm preventives, Trifexis does not kill adult heartworms. Speak to your veterinarian about treatment options if your dog is diagnosed with an adult heartworm infection.

Learn more about heartworms

Which heartworm lifecycle stage does Trifexis control?

Trifexis acts in the same way as other monthly heartworm preventives, by killing L3 and L4 larval stages before they molt to the final adult stage.

Learn more about the heartworm lifecycle

Does Trifexis protect against ticks?

No, Trifexis is not labeled to kill or repel ticks. Trifexis is labeled for the prevention of heartworm disease on dogs, to kill adult fleas on dogs and to treat and control adult hookworm*, roundworm and whipworm infections in dogs. There are no known contraindications between Trifexis and medications commonly used against ticks.

*A. caninum

My dog has tapeworms. Will Trifexis get rid of those?

No, Trifexis will not treat a tapeworm infection. Trifexis is indicated for the prevention of heartworm disease in dogs, for the prevention and treatment of flea infestations on dogs and the treatment and control of adult hookworm*, adult roundworm and adult whipworm infections in dogs and puppies 8 weeks of age or older and 5 pounds of body weight or greater.

*A. caninum