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Product Information

Trifexis is a monthly, chewable tablet for dogs that kills fleas, prevents heartworm disease, and treats and controls adult hookworm, roundworm and whipworm infections. Trifexis combines two trusted active ingredients to provide protection for your dog against these dangerous parasites. Trifexis starts working within 30 minutes from administration of this medicine to kill fleas and has been proven to kill all biting fleas within 4 hours. Trifexis also kills flea eggs before they can mature, which puts an end to the flea life cycle. Trifexis prevents heartworm disease by killing microfilariae and larvae from maturing into adult heartworms. Trifexis comes in a tasty beef-flavored tablet (made from pork liver and hydrolyzed soy) for ease of administration to your dog.


Dogs (at least 8 weeks of age and weighing at least 5 lbs)


Trifexis is used to prevent heartworm disease, and treat and control adult hookworm, roundworm and whipworm infections.

Active Ingredients

Spinosad & Milbemycin Oxime


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. Make sure to tell your veterinarian what other medication you are giving to your pet. Quite often your veterinarian may prescribe two different medications, even if a drug interaction may occur. In this case, your veterinarian may vary the dose and/or monitor your pet more closely. This medication is generally well tolerated with other commonly prescribed medications. Contact your veterinarian if your pet experiences any unusual reactions when different medications are given together. Allergic reactions to medications may occur. Be sure to inform VetSource and your veterinarian if your pet has any known drug sensitivities or allergies. If your pet displays symptoms of an allergic reaction, call your veterinarian immediately or go to a veterinary emergency clinic. Symptoms may include but are not limited to: swollen lips, tongue, face, airways; difficulty breathing; agitation; profuse salivation; vomiting; widespread hives and itching.

Side Effects

Side effects may include nausea, vomiting, diarrhea, loss of appetite, decreased activity, itching, redness and inflammation of the skin. If you notice anything unusual, contact your veterinarian.


Trifexis should be given orally as directed by your veterinarian. Give Trifexis with food for maximum effectiveness.

Product Notes is not a licensed pharmacy.

All prescription products (excluding prescription food) fulfilled by VetSource. VetSource only ships to the contiguous 48 US states.

You must have a valid veterinarian-client-patient relationship to request prescription products from VetSource. Prescription requests are subject to a drug utilization review by a licensed pharmacist at VetSource for patient safety.

All prescription products (excluding prescription food) are FDA approved, or EPA licensed, to be sold in the US.

Most prescription products cannot be returned, however, Hill's Prescription Diet products can be returned.

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Trifexis for Dogs (Green) - 20-40 lbs - 6 count

1 review
$122.89 SALE

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by PowerReviews
TrifexisDogs (Green) - 20-40 lbs

(based on 1 review)

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Reviewed by 1 customer

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(6 of 9 customers found this review helpful)


bad experience

By J Pug

from New York, NY



      Best Uses

        Comments about Dogs (Green) - 20-40 lbs:

        I switched my pug to trifexis and after about 2 months she began getting bumps on her ears. I took her to the vet- he put her on antibiotics but wasn't 100% sure what the bumps were. I asked if it could have been a side effect from the trifexis since that was the only thing I could think of that had changed for her and he assured me it was not. He said if the antibiotics did not work they would biopsy the bumps. I used the antibiotics and the bumps did not go away. I decided to not continue with the trifexis just to see what happens. I went back to her old flea prevention medicine and the bumps began to get smaller after the first month and then were completely gone by the 2nd month. I was skeptical with using the product because I did see mixed reviews but my vet assured me it was safe. I would definitely not recommend this product.

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