Levothyroxine is a prescription medication used to treat underactive thyroid (hypothyroidism) and other thyroid problems. Levothroxine is a synthetic thyroid hormone, which replaces the body's reduced levels of natural thyroid hormone.
This medication comes in tablet form and is taken once in the morning on an empty stomach, with a glass of water.
Common side effects of levothyroxine include tremors, change in appetite, and irregular heartbeats.