The treatment of choice for Hashimoto's thyroiditis is typically synthetic T4 or thyroxine (levothyroxine). Brand names for this medication include Synthroid , Levothroid and Levoxyl . The medication must be taken indefinitely, and successful treatment alleviates the symptoms and signs of hypothyroidism. Without medication, there is very little chance the thyroid would be able to maintain hormone levels within the normal range, and symptoms and signs of hypothyroidism would occur or worsen. The dosage of levothyroxine may need to be modified after checking TSH levels once yearly. Adjustment of the dose may also be required in pregnant women.