Eltroxin 100mcg tablets contain Thyroxine sodium as the active ingredient. This medication comes in a pack of 100 tablets and is manufactured by Aspen Pharmaceuticals. Each tablet contains 100 micrograms of Thyroxine sodium. Eltroxin is a prescription medication that contains synthetic thyroid hormone (Thyroxine sodium). The tablets come in a white plastic container with 100 tablets. The packaging includes both a box and bottle clearly labeled with the medication name, strength, and manufacturer information.