Simparica Trio is FDA approved and available to be purchased without a vet's prescription in over 40 countries around the world. The three active ingredients in Simparica Trio are sarolaner, moxidectin and pyrantel pamoate, which work together to provide protection against fleas, ticks and intestinal parasites. Sarolaner kills fleas quickly and continues killing them for up to 35 days. Moxidectin eliminates hookworms, roundworms and whipworms for up to 3 months after administration. Finally, pyrantel pamoate works by paralyzing the worms so they are eliminated from the body when your pet passes stool.