In uncomplicated cases, generally the initial dose is 50 micrograms per day, with doses increased at 3 to 4 week intervals until it reaches between 100 and 150 micrograms. Few patients with hypothyroidism ever require more than this, although pregnant women may require higher than normal doses. On the other hand, young adults with a short history of hypothyroidism might take a full initial dose. A recent study indicated that some patients may be able to maintain normal thyroid levels by taking one large weekly dose, rather than small daily ones, which could help compliance. Levothyroxine is slowly assimilated by body organs, and it usually takes three to six weeks of treatment for an improvement in symptoms in adults.
Patients start feeling better two to three weeks after beginning treatment.
Other conditions, such as goiter and high LDL cholesterol levels decline more gradually. Once the proper dose has been established to normalize thyroid blood levels, patients usually see their physicians once a year for a brief evaluation. Thyroid failure is an ongoing process, usually due to chronic inflammation of the gland. A dose of thyroid medication that is appropriate for a patient one year may be too low the next. To maintain normal thyroid levels, some patients may need to take gradually increasing doses of thyroid hormone every year or two.