Levothyroxine is a thyroid hormone that is used to treat hypothyroidism. This hormone provides extra thyroid to the body, reversing symptoms of low levels of thyroid such as slurred or slowed speech, lack of energy, weight gain and hair loss.
This medication should only be used to treat thyroid conditions; it should not be prescribed solely for the purpose of helping patients lose weight. If a patient takes this medication who has normal thyroid levels, it can result in thyroid toxicity. Taking this medication in conjunction with amphetamines, a stimulant that is used in weight loss pills, can be fatal.