Highly effective Panacur® PowerPac equine dewormer by Merck Animal Health (5 x 57 gram syringes) offers a complete treatment course against the predominant internal parasites in horses. Each syringe is a double dose of fenbendazole for a 1,250 lb horse. It contains a unique apple cinnamon flavor. Panacur PowerPac is designed to be given for five consecutive days to a individual horse. 5 syringes, 57 grams each.