Trifexis FAQs - Top Heartworm & Flea Protection for Dogs Protection from Fleas, Heartworm, and Intestinal Worms

Trifexis FAQs - Top Heartworm & Flea Protection for Dogs
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vet verified PetCareRx Staff Veterinarian DVM

Pests like fleas and worms can lead to very serious health issues, and some pretty hefty vet bills, too. Prevent heartworm, fleas, and intestinal worms with Trifexis for dogs.

Dogs are our best friends, and unfortunately, they're also attractive buddies for fleas, worms, and other parasitic creatures. Fleas will bite and cause itching on your pet's skin, and can also transmit tapeworm. Heartworms are internal parasites transmitted by mosquito bites that clog your dog's arteries and can cause heart failure. Hookworm, roundworm, and whipworm are all pretty gross too. Luckily, Trifexis is an easy monthly preventative medication that stops all of these pests.

Here we cover some frequent questions about Trifexis.

What is Trifexis?

Trifexis is a beef-flavored tablet that you give to your dog to eat once a month. It then gets to work. The primary ingredients in Trifexis are spinosad and milbemycin, which kill adult fleas by attacking their nervous system. You can compare Trifexis to other heartworm and flea and tick medications with our handy comparison chart.

Where Can I Find Trifexis Coupons?

To find manufacturer coupons for Trifexis, check their website. Also, we here at PetCareRx are constantly running promotional deals on various flea & tick, and heartworm medications.

What Are Trifexis Side Effects to Look Out For?

Collies should never take Trifexis since they have an intolerance for milbemycin. Dogs with epilepsy should only be given Trifexis if approved by your vet. If your dog experiences vomiting, itching, ear redness, skin inflammation, loss of appetite, diarrhea, or lethargy, talk to your vet.

What Are Common Trifexis Prices?

Market package prices for Trifexis are in the $120 range, depending on the size of your dog and the dosage you need. Trifexis on PetCareRx is usually available at closer to $100, and on Protection Plus, closer to $80-$90!

By signing up for Protection Plus by PetCareRx, the first-ever comprehensive savings plan for pets, you'll get savings of up to 75% on pet medications and preventatives. Find out how much a membership will help you save.

Where Can I Find Trifexis Reviews?

You can read reviews here on PetCareRx! Check out reviews for Trifexis now.

When Trifexis is Safe for Your Dog

When Trifexis is Safe for Your Dog

When Trifexis is Safe for Your Dog

From K9 Advantix II to Frontline Plus, there are numerous flea medications available for dog owners to choose from. Each has its own benefits and possible side effects that can impact your canine's health. Recently, the medication Trifexis has been making waves around the veterinary world, as some pet parents claim it's been responsible for the death of their dogs. Fatal adverse reactions were blamed on the flea control medication, but when properly administered, Trifexis is safe for dogs.

Handling drug regulations

Trifexis has been approved by the U.S. Food and Drug Administration as a prescription medication for dogs to treat flea infestations. This is different than topical pesticides, which are regulated by the Environmental Protection Agency as they don't exhibit systemic activity. According to The Whole Dog Journal, the FDA's Center for Veterinary Medicine is responsible for collecting and analyzing reports on adverse effects of animal medication. The agency keeps an extensive database of these reactions to provide vets with warning signs of symptoms that weren't detected during pre-market testing. Despite its FDA approval, veterinarians have grown concerned that administrations of Trifexis have been involved or solely responsible for dog deaths. Yet, the CVM report included statistics that indicated owners were improperly issuing the drugs to their dogs.

Using Trifexis safely

The monthly tablet aims to kill and prevent fleas, heartworms, hookworm, and other parasites that can affect dogs. However, it's meant to be administered orally. The CVM statistics showed that some owners had given Trifexis to their canines either intraocularly or cutaneously, meaning in the eyes or on the skin, respectively. Given the reporting discrepancies, the data should be carefully considered. Its accuracy regarding adverse effects is dependent on the quality of the information received from veterinarians or dog owners. In addition, the CVM noted that the frequency of reporting for a product can vary over time and may increase when media publicity occurs. Because of this, it's important that dog owners pay attention to the usage directions provided by both veterinarians and the product label on the prescription bottle. They should also watch for any signs of adverse reactions, such as vomiting, lethargy, itching, decreased appetite, and diarrhea. Before administering Trifexis, dogs should be tested for existing heartworm infections. It shouldn't be used in addition to medications that include ivermectin. provides owners access to medications at discounted prices and includes specific directions and warnings for each prescription. Adhering to them makes Trifexis safe for dogs and ensures a healthy canine.

Frequently Asked Questions

How long does it take for Trifexis to kick in?

Trifexis, a monthly chewable tablet for dogs, begins to kill fleas within 30 minutes of administration and prevents flea infestations within 24 hours. It also begins to kill heartworm larvae and eggs within a month and prevents heartworm disease within 3 months. Additionally, it also kills and controls roundworms, hookworms, and whipworms.

Can you give Trifexis without food?

Trifexis should be given with a meal to ensure maximum effectiveness. The package insert states that "Trifexis should be administered with food. If a dose is missed and it is within one day of the next scheduled dose, administer the missed dose with food. If a dose is missed and more than one day has passed since the last scheduled dose, administer the missed dose as soon as possible and return to the regular schedule. Do not administer two doses at once.”

Why does my dog still have fleas after using Trifexis?

There can be several reasons why your dog may still have fleas despite being on Trifexis. Incorrect dosage, resistance, environmental factors, and not all fleas on the dog being killed at the time of administration are some possible explanations. Make sure you are giving your dog the correct dosage of Trifexis as prescribed by your veterinarian. Fleas can develop resistance to certain medications over time, making them less effective. Also, fleas can also come from the dog's environment (e.g., other pets, yard, etc.). You may need to address fleas in the environment as well.

What happens if I give my dog Trifexis and he has heartworms?

Trifexis is a monthly oral medication that is used to prevent heartworm, fleas, and other parasites in dogs. However, if a dog is already infected with heartworms when they are given Trifexis, it will not effectively treat the infection. Heartworm infection is a serious and potentially life-threatening condition requiring immediate veterinarian treatment. If a dog is already infected with heartworms when given Trifexis, the medication will not kill the adult heartworms, and that could cause the dog's death. It is crucial to have your dog tested for heartworm before starting any heartworm prevention medication. If your dog tests positive for heartworm, it is necessary to have them treated by a veterinarian before starting any prevention medication. It is also important to give the medication on time and regularly. If you miss a dose or give it late, it may not be as effective in preventing heartworm infection.

What happens if you miss a month of Trifexis?

Missing a month of Trifexis may leave your dog unprotected against fleas, heartworms, and other parasites. As a monthly preventative, Trifexis works by killing any parasites that may be present on the dog's skin and fur or in the dog's bloodstream. If a dose is missed, it can take longer to kill existing parasites and may reduce the effectiveness of the medication overall. It is important to administer the medication on schedule, as directed by your veterinarian. If you miss a dose, it is best to give it as soon as possible and then return to the regular schedule. If you are unsure of what to do, it is best to consult with your veterinarian for guidance.

More on Flea Protection

When to Use Trifexis vs Sentinel for Dogs
Differences of Trifexis vs Advantage Multi for Dogs
Combining Flea Treatments: What You Need to Know
Flea Treatments for Dogs with Sensitive Skin

This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis, or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

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