Simparica is a monthly chewable tablet that is used to treat and prevent flea and tick infestations in dogs. It is available only with a prescription from a veterinarian. Simparica is a fast-acting oral flea and tick preventative that begins killing fleas and ticks within hours of administration and remains effective for one month. It is indicated for the treatment and prevention of flea infestations (Ctenocephalides felis), and the treatment and control of tick infestations . Simparica is safe to use year-round without interruption and can be given directly to the dog or mixed with food. It is important to note that Simparica may cause neurologic signs such as tremors, unsteadiness, and/or seizures in dogs with or without a history of neurologic disorders. The most common adverse reactions in clinical trials were vomiting and diarrhea.