Levothyroxine helps regulate your metabolism and energy, as it is a replacement for a hormone your thyroid normally produces that does this. Levothyroxine is used to treat low thyroid hormone levels in your body, called hypothyroidism. It is also prescribed for hormone imbalances from radiation treatment, surgery or an enlarged thyroid gland, also called goiter. If you suddenly stop taking levothyroxine, your body goes through withdrawal. It is not recommended that you stop taking levothyroxine unless your doctor advises you to do so.
Levothyroxine withdrawal may cause hypothyroidism, or underactive thyroid. Hypothyroidism causes weight gain, fatigue, depression and sensitivity to cold because your body does not have enough thyroid hormone so your body processes slow down. Patients with thyroid cancer may suffer acute hypothyroidism because of levothyroxine withdrawal.
Depression and Anxiety
Thyroid cancer patients stop or reduce their dosages of levothyroxine before follow-up or diagnostic procedures. Reducing your dosage or stopping altogether can cause depression and increased anxiety, according to a study published in December 2005 in the "European Journal of Endocrinology." The study found that there is a consistent pattern of increased anxiety of around 44 percent and depression of around 17 percent in patients undergoing levothyroxine withdrawal.
Thyroid hormones help in the modulation of glucose metabolism, your body's insulin response to blood sugar. Levothyroxine withdrawal can cause a state of insulin resistance, according to a study published in the June 2009 issue of "Thyroid." Four patients were tested after six weeks of levothyroxine withdrawal and were found to have a significant degree of insulin resistance, which resulted in reduced glucose disposal -- how fast your body stabilizes blood sugar. Blood glucose affects your body's energy level and ability to burn fat.
Another symptom of levothyroxine withdrawal is pale or dry skin. The moisture content of the skin is affected by the reduced amount of hormone available, which also causes hypothyroidism. In addition, other physical effects include dry brittle nails and hair loss.
- Drugs.com: Levothyroxine; April 26, 2010
- American Thyroid Association: Hypothyroidism; 2005
- "European Journal of Endocrinology"; Short-term hypothyroidism after Levothyroxine-withdrawal in patients with differentiated thyroid cancer: clinical and quality of life consequences; L.H. Duntas; 2007
- "European Journal of Endocrinology'; Health-related quality of life, anxiety and depression in thyroid cancer patients under short-term hypothyroidism and TSH-suppressive levothyroxine treatment; S. Tegay: Dec. 2005
- MedlinePlus; Hypothyroidism; April 10, 2009
- "Thyroid"; Acute Thyroid Hormone Withdrawal in Athyreotic Patients Results in a State of Insulin Resistance; G. Brenta, et al.; June 2009