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New Flea & Heartworm Prevention in One Tablet!

2011 March 25


Trifexis is the most complete dog preventative monthly tablet veterinary medicine has ever seen!

Ever heard of it?  The fabulous Comfortis (pronouced Come-FOR-tiss)  flea pill for dogs combined with the safe and effective milbemycin= Trifexis(pronounced Try-fex-iss).  Now you do not have to give Comfortis and a different heart worm prevention!  You can just give one monthly product!

Did You Know?

Trifexis active ingredients are Spinosad and Milbemycin.

Trifexis is a once-a-month yummy flavored tablet for dogs that kills fleas and prevents heart worm infection.  It also prevents and controls the intestinal worm infections:  hookworms, roundworms, and whipworms.

Call All Pet Care Hospital and ask or mention the new flea and heart worm pill Trifexis at your next check-up to learn the ideal preventatives for your pet.  You will save time and money!

Letter to Our Clients,

The most up to date, progressive parasite prevention products include Trifexis, Revolution feline, Advantage Multi, Advantix, Comfortis, Heartgard Plus, Interceptor & Preventic.

We have decided to phase out supplying the following:  Advantage and Frontline.

In our attempts to better serve you, we occasionally find it necessary to re-evaluate which veterinary products best fit with our practice standards.

We would like to stress that the efficacy of these products was not a factor in this decision.  Our goal in making this change is simply to improve our ability to provide you with the best service possible.  Eliminating the above products will allow us to stay on top of new developments in veterinary medicine by making room for newer products as they come to market.

For those of you who wish to continue using these products, Advantage & Frontline are readily available over the counter at the large pet stores.  We will happily approve prescriptions, just give us a call and we will help you set up your own online pharmacy account 877 DR TRULI

We apologize for any inconvenience this may cause however we believe that our decision will improve our ability to provide all of our clients with the most up to date progressive veterinary care.

Thank you,

Dr. Springer

Trifexis Warning

If your pet undergoes an off-label treatment, typically used for treatment of demodectic mange, with the drug ivermectin, you must not use spinosad, one of the active ingredients in Trifexis.  Serious, and possibly deadly side-effects have been reported from the combination of spinosad and ivermectin.

Trifexis Reference

All Pet Care Hospitals Flea & Tick Page

Trifexis official website

Pharmaceutical Industry Today official news release

Note August 15, 2011:

Many people have been commenting on this website asking about their personal dogs.  If you are not a registered client of Dr. Springer aka Doc Truli, we cannot answer medical questions regarding your pet.  Please, please, call your family veterinarian for personal advice!

31 Responses leave one →
  1. April 21, 2011

    I’m wondering if anyone has reported dogs developing cysts after being on Trifexis for 2-3 months?

    Both of my 2 young (2 yrs) Yorkie mix dogs have suddenly developed a cyst on their backs and I’m trying to determine why.

    Two other foster dogs I have that are not on Trifexis do not have cysts.

    • JLaw permalink*
      April 23, 2011

      Dear Dollie,

      There’s absolutely no reports of cysts and Trifexis. The pattern you are seeing with 2 of the dogs having cysts and 2 not is coincidence. When clinical trials are run, there are many, many dogs assigned to groups and tested in a double-blind trial where the dog’s caretakers also do not know who is getting what. Then statistical analysis is applied to find some useful meaning from the results.

      If two of your little ones have new cysts, we would be happy to check them out for you. Sometimes a physical exam reveals a simple answer and can ease your worries once and for all.

      Doc Springer

  2. Ingrid Worthy permalink
    June 2, 2011

    What are the other ingredients in Trifexis? My dog has food allergies so I wanted to know what it is flavored with. Is it safe for dogs with food allergies?

    • JLaw permalink*
      June 3, 2011

      Dear Ingrid,

      Trifexis was made with food allergic dogs in mind. The top food allergies of dogs in the United States are beef, chicken, corn, soy, and egg. Proteins cause the allergic reactions. The protein in Trifexis (and Comfortis) is pork.

      Veterinary dermatologists even recommend Trifexis during a food allergy elimination trial because it is so unlikely to cause a problem for allergic dogs.

      -Doc Truli

      • Ingrid Worthy permalink
        June 4, 2011

        That’s great!!!!! I thought we had no oral alternatives since my old unflavored medicine isnt being produced right now and my doggie gets freaky when we try to apply topicals. What can I say – my dog is sweet but if she thinks you’re trying to treat her with anything medical, she flips out. This is really good news for us. Thank you so much!

  3. Melanie Skelton permalink
    June 21, 2011

    my dogs currently take a heartworm prevention with ivermectin in it. How long do i need to wait before using Trifexis?

    • JLaw permalink*
      July 3, 2011

      Dear Melanie,
      If your dogs are taking an ivermectin preventative, then they will need the Trifexis for heartworm prevention 30 days after the ivermectin product dosing. In the meantime, if you need flea prevention, I recc’d Comfortis.
      Doc Springer

  4. Sandy Martin permalink
    July 25, 2011

    I was wondering if a side-effect of Trifexus is extremely dry, flakey, irritated skin? My newfoundland has been on the medication for a month now and within that month his skin has become very flakey. He tends to have skin issues, but has never had dry skin in the summer before. He is scratching himself also, so I am assuming the dryness is causing discomfort. He also has some redness on his tail. Could you tell me if this could be a side-effect from the Trifexsus?

  5. Lily permalink
    July 29, 2011

    My dogs pitbull mixes both young were given ivermectin and trifexis in the same month what would be symptoms and how long should i be watching for signs of a problem and how long would it take for it to cause a problem if it were going to ba a problem i am really scared for my babies so any information would be greatly appreciated

    • JLaw permalink*
      August 2, 2011

      High dose ivermectin (like you would use for demodex) has been shown to cause seizures if given with Spinosad (ingredient in Trifexis and Comfortis.) It’s only some dogs, and the effect goes away when you stop the meds. If you are still giving the combo and see any tremors or seizures, contact your veterinarian right away for emergency care.

  6. brittany permalink
    August 4, 2011

    my vet prescribed me trifexis without testing for heartworms. ive heard you need to test before giving trifexis but my vet said no. im a little concerned about giving my dog trifexis now. i dont want anything fatal to happen if she does happen to have hearworms. what should i do?

    • JLaw permalink*
      August 16, 2011

      Dear Brittany,

      I just saw a Chihuahua that had hidden heartworms and her owner gave the Trifexis meant for her other dog! She went into anaphylactic shick and needed intensive care to recover.

      Ask your vet again. Perhaps you misunderstood.

      Doc Springer

  7. Jill permalink
    August 8, 2011

    My 8 month old yorkie has had 2 doses of trifexis and we just realized on the same day of each dose he has seizure like symptoms without the shaking and jerking. He is out of sorts, dazed, looks and acts like he is “high”. I’m not sure if this is a severe side effect of this medicine or he is really having a seizure. Can this be the trifexis and he needs to stop taking it?

    • JLaw permalink*
      August 16, 2011

      Call your vet immediately! Yorkies also have portosystemic shunts and other problems that cause an unnatural, unhealthy “high.” It’s worth a call to the vet!

  8. kacey permalink
    August 9, 2011

    I have a 3 yr old border collie retriever mix. He currently is using frontline and heartgard without any problems other than the messy and drippy frontline. Would it be more trouble than its worth to switch to the trifexis? I like the idea of 1 pill per month doing the job of both the heartgard chewable and frontline drops, but I don’t want my baby to suffer any adverse effects. Any advice would be greatly appreciated. Oh and I heard somewhere that collies and other herding breeds had a bad reaction to the trifexis. Is there any truth to that? Thanks!

    • Doc Truli permalink*
      August 16, 2011

      Collies and herding breeds have an altered MDR-1 gene which is used to process Ivermectin, which is not an active ingredient of Trifexis, but is the active ingredient of some of the competing brands. Click the link to go to the University of Washington’s page about testing your dog for the gene.

      Call 877 DR TRULI tp schedule a genetic comsultation for your dog.

  9. JLaw permalink*
    February 20, 2012

    Dear Donna,
    Our own Dr. Springer has been providing answers to the questions that seem to be on everyone’s mind. The article on our website itself answers most of the questions. We also answer your questions during a consultation here in the hospital. Thank you for reading and thanks for your feedback.

  10. Miranda permalink
    April 20, 2012

    I have a 2 year old english bulldog who has been on advantix and interceptor. I now can not get interceptor because of a manufactoring hold or whatever the issue. I am thinking Trifexis would be a better option, #1 advantix gets everywhere (ie hands, furniture) since her hair is short and #2 i believe it is slighty cheaper than the 2 drugs. We are planning to breed her on her 4th heat which will be Sept 2012. I’ve read a study or 2 about using it that just say use caution. Ultimately, I know it is a question for my vet, but I was just wondering what your opnion about breeding and using trifexis is?

    • JLaw permalink*
      April 21, 2012

      Dear Miranda,
      I have no opinions beyond the FDA-approved label and the research. Overdoses of Trifexis in controlled research settings have been shown to cause low birth weight puppies, and the higher the overdose, the weaker, slower to breathe, and the smaller the puppies. Since heartworms do not market themselves, they do not have research to show all the damage they do to the mom and pups. We know heartworms cause pulmonary thromboembolism, clotting disorders, heart failure, and a host of other diseases and eventual certain death. Everything is a balancing act and an individual decision; no choice is without risk. If you choose to breed your dog, then there are compounded risks because anything you give to mom can also affect the puppies.

      Your personal, hands-on veterinarian is the best source of advice about your situation. Beyond that, I applaud you for reading the FDA label for the medication. All FDA-approved and pending drugs have information that can be accessed online. It is a valuable resource.

      Doc Springer

  11. June 30, 2012

    My 4 month old pitbull mix took Trifexis on June 18th. The vet recommended me take Ivermectin for demodex. She knows that he took Trifexis on the 18th, and recommended to start dosage of Ivermectin today (June 30th) with a starting dosage of .2ml. I spoke with a different vet over the phone and they said he should start Ivermectin on the 18th of July. I feel that’s too long to wait, because I don’t want his condition to get worse with Demodex. I don’t know if i should listen to a vet whom i talked over the phone, or the vet who physically saw my puppy. I’m also a little hesitant to have him take the Ivermectin because there was a second opinion. What should i do? He has an appointment to be seen in two weeks for re-weigh and dosage adjustments for Ivermectin.

    • Doc Truli permalink*
      July 4, 2012

      Is this a trick question, “Trish” from “”? High dose ivermectin, such as you are writing about should never be given with Trifexis (or Comfortis), as there is a known side-effect of seizures from mixing the off-label high-dose ivermectin with spinosad, the active flea-killing ingredient in Trifexis and Comfortis.

      Your puppy needs an alternative treatment for demodex, or an alternative flea medication for now. Please see your regular veterinarian for a plan, as you cannot mix Trifexis or Comfortis with high-dose Ivermectin for demodectic mange treatment.

      If you live in Pinellas County, Florida, please call (877) DR TRULI, and I will see your puppy personally.

      Doc Springer

      • July 4, 2012

        Thanks for your reply. I know absolutely nothing about this, so I am not pulling anyone’s leg. I had two different opinions from two different vets regarding this, and I needed a third. My puppy’s vet will not be available for a few weeks. Is there an alternative medication for Demodex? I would like to bring it up with the vet and ask why she hadn’t prescribed that instead.

        • JLaw permalink*
          July 7, 2012

          Hi Trish,
          There are different wasy to treat demodex. If you go to you can read a whole detailed article about demodex. But briefly, the FDA-approved treatment is Mitaban dips (they are expensive as all-get-out and must be done i the hospital and in most US states, the hospital must have a special sewage-handling system to use it. For example, one hospital I worked at charged $80 a dip and you needed at least 3 of them before you had a chance of a cure. Some dogs need 6,10, 12 or more dips!) “Off-label” treatment is the oral Ivermectin. Another treatment is daily Interceptor (milbemycin) tablets. This is waaaaay expensive, and right now Interceptor is on a manufacturing hold in the United States. (“Off-label” means it is not FDA-approved, which about 75% of veterinary medications are “off-label,” but there is a hisroty of use and usually many research studies so it is part of the standard of care.)

          Demodex is tricky to cure because it is a natural organism on dog skin, but when it overgrows and makes them sick, it is hard to get under control. Also, your dog should be on antibiotics to kill harmful skin bacteria. Doggy Dermatologists have discovered that bacteria and demodex synergize: they change the pH and other features of the skin to make each other grow better. So I usually recommend oral antibiotics until the skin starts to show signs of healing.

          Good Luck. It is tricky to treat demodex. You’ll have to have good communication with your veterinarian and frequent recheck visits in order to get your puppy healthy again.

  12. Dwight permalink
    September 1, 2012

    One of our 10 month old American Pitbull puppies recently had what we were told was a toxic reaction to ivermectin due to an altered mdr gene. She had been taking ivermectin for a month and had gradually increased to the 1.8ml daily dose to be taken for 2-3 months. She was given her dose of ivermectin in the morning and was given her Trifexis with dinner. Later that evening she awoke suddenly and was experiencing constant seizures and could not walk or see. She was rushed to the emergency animal hospital where she was given iv valium overnight until the seizures stopped. She was released to us the next day and we took her to her doctor. We were told by both the emergency doctor and our regular veterinarian that it was not the Trifexis because these two drugs were different drugs for different conditions. We almost lost her due to their lack of knowledge of this drug combination. Thank you for making this information available online.

    • JLaw permalink*
      September 4, 2012

      There are some illogical statements in your comment.

      1) If your dog had MDR deficiency gene, the valium IV would have made the seizures permanent and killed your dog. There is a test through Washington State University Vet Hospital, where you can order a cheek swab test and pay $70 to find out!

      2) If your dog is taking daily ivermectin (off-label) for demodicosis, then you do not need other heartworm preventative (like Trifexis). You may need flea preventative, but that’s it.

      3) As you noticed in the previous comments, there is a published contraindication to spinosad (one active ingredient in Trifexis, and the active ingredient in Comfortis) and ivermection high dose given together. These should not be prescribed together.

      I’m so happy your girl is doing better. She should be normal from now on.

      -Doc Springer

      • Dwight permalink
        September 8, 2012

        Thank you for your response. In your opinion, are we safe to give her Trifexis now that she is no longer taking the ivermectin?

        • JLaw permalink*
          October 10, 2012

          Dear Dwight,
          Thanks for reading my response. I really need to examine your dog, your situation, and take personal responsibility for my opinion in order to comment on that. As a veterinary physician, I am held to a higher standard by society. When I give my opinion, people count on it to make decisions in their life. Your question is good and should be answered by your veterinarian.
          -Doc Springer

  13. Mary permalink
    April 30, 2013

    Hello, my dog has allergies so our vet started him on .2ml ivermectin orally monthly for heartworm prevention. Now she wants to switch him over to trifexis for the added flea prevention benefit. She said that he can start 30 days after his last dose of ivermectin. Is this alright? If not how long do we wait? Thank you for your time, I just worry about my boy!!


    • JLaw permalink*
      May 7, 2013

      Dear Mary,

      As you know, we cannot give veterinary advice without a valid veterinary-patient-client relationship. This means we need to meet you and examine your pet in person in order to advise you. Please refer your question to your veterinarian, who knows your pet and the medicine they are prescribing.

      Good Luck!
      Doc Springer

  14. Donna Freeman permalink
    September 10, 2013

    Can you tell me how long Trifexis stays in a dogs system? My vet has recommended ivermectin for my dogs mange, and I don’t want to start it too soon! Thank you!

    • JLaw permalink*
      December 14, 2013

      I just called Novartis and asked this very question for a patient of mine. Your vet should call for you and answer that question.

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