What is Trifexis® (SPINOSAD + MILBEMYCIN OXIME)?

What is Trifexis, and what does it protect against?

Trifexis is a monthly, chewable tablet for dogs. Trifexis kills fleas and prevents flea infestations, 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.

*Ancylostoma caninum

What are some of the benefits of Trifexis?

  • Trifexis is an oral monthly product that rapidly kills fleas and also is effective in preventing heartworm disease and treatment and control of adult hookworm (Ancylostoma 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 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 13.5mg/lb (30mg/kg) spinosad and 0.2 mg/lb (0.5 mg/kg) milbemycin oxime according to body weight.

Trifexis Dosing Chart

How well does Trifexis work?

  • In a well-controlled laboratory study, Trifexis was 100% effective against induced heartworm infections 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 (Ancylostoma 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 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 over 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.

Is Trifexis FDA approved?

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

Is Trifexis safe?

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.1 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, lethargy, diarrhea, itching, loss of appetite, trembling/shaking, incoordination, seizures and excessive salivation.

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 is a safe product when used according to label directions. The active ingredient, spinosad, is produced by a bacterium first isolated from natural sources (a soil sample collected in the Caribbean).Spinosad demonstrates selective toxicity to the flea’s nervous system, but has low toxicity to mammals and other non-target organisms.3 However, as with all medications, sensitivities due to individual animal variation can occur.

How quickly will Trifexis kill fleas?

In a laboratory study of spinosad alone, spinosad, an 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.

Will Trifexis kill heartworms?

Trifexis prevents heartworm disease 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.

Which heartworm lifecycle phase does Trifexis control?

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

Does Trifexis protect against ticks?

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

*Ancylostoma 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, for the prevention and treatment of flea infestations 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.

*Ancylostoma caninum