Trifexis 20-40lbs (Green)
Before starting Trifexis, dogs should be tested for heartworms because giving preventatives to dogs that have adult heartworm infection can be harmful or fatal to the pet. If infected, your veterinarian may decide to treat your dog with a heartworm adulticide.
Heartworms produce millions of microscopic “baby” heartworms, called microfilaria. In dogs carrying a high number of circulating microfilariae, mild, brief hypersensitivity reactions such as labored respiration, vomiting, salivation, and lethargy have been noted in some dogs treated with milbemycin oxime. These reactions are thought to be caused the by release of protein from the dead or dying microfilariae.