Trifexis is a popular pet medication that prevents heartworm, treats and controls other types of worms, and kills fleas in dogs. Trifexis comes as a chewable tablet that is given to dogs once a month, and many pet owners appreciate that it can replace certain topical medications (such as a flea dip). However, like all prescription drugs, Trifexis comes with a risk for certain side effects, and dog owners should make sure they familiarize themselves with these possible adverse effects before administering this preventive medication.
Most Common Trifexis Side Effects
Vomiting is the most frequently reported Trifexis side effect, occurring in approximately 6% of dogs who take the chewable oral tablets. Fortunately, no severe or prolonged vomiting has occurred in field studies, and dogs who do vomit after taking Trifexis typically recover quickly. If your dog vomits within an hour of taking their tablet, talk to your vet; you may need to administer another dose to make sure your dog gets the medicine he or she needs.
Other possible side effects of Trifexis include itching (affecting about 4% of dogs), lethargy (2.6%), and diarrhea (2.3%). Some dogs also experience a temporary loss of appetite and may not eat their food at their usual meal times. Serious side effects are rare, but you should still monitor your dog after administering Trifexis and report any side effects that last a long time or get worse.
Trifexis Pet Medication Pack
Signs of an Overdose
Trifexis is available in different dosage strengths, and it’s important to always administer this medication in the dose your vet has prescribed for your dog. Administering too much of the medication in one dose can lead to overdose symptoms, including vomiting, excessive drooling, coughing, vocalizations and decreased activity levels. If your dog is experiencing any overdose symptoms, call your vet or the Pet Poison Helpline (855-213-6680) right away.
The Importance of Heartworm Testing
Before your dog starts a regimen of Trifexis, it’s very important to have him or her tested for heartworms. If your dog does have a heartworm infection, the adult heartworms can produce millions of microscopic “babies” (called microfilaria, which circulate in your dog’s bloodstream. If Trifexis kills existing microfilaria, it is believed that the dying parasites release a protein that can cause vomiting, labored breathing, increased drooling, and lethargy in your dog.
Once your dog has started taking Trifexis, you should continue having him or her checked for heartworms on an annual basis. This can be done at a routine vet check-up.
Follow Your Vet’s Instructions
While reading about possible side effects and overdose symptoms of Trifexis can be understandably scary for any dog lover, keep in mind that the FDA has deemed this pet medication safe, and the actually risk for side effects is very low when it is administered as prescribed. Always follow your vet’s instructions for dosing your dog with Trifexis and the benefits of parasite protection should outweigh the slight risk of side effects. For more information about prescription pet medications, visit our Pet Medications Page.