The purpose of treatment is to replace the deficient thyroid hormone. Levothyroxine is the most commonly used medication. The lowest dose effective in relieving symptoms and normalizing the TSH is used. Life-long therapy is needed. Medication must be continued even when symptoms subside. Thyroid hormone levels should be monitored yearly after a stable dose of medication is determined.

After replacement therapy has begun, report any symptoms of increased thyroid activity (hyperthyroidism) such as restlessness, rapid weight loss, and sweating.

Myxedema coma is a medical emergency that occurs when the body's level of thyroid hormones becomes extremely low. It is treated with intravenous thyroid replacement and steroid therapy. Supportive therapy of oxygen, assisted ventilation, fluid replacement, and intensive-care nursing may be indicated.

With treatment, return to the normal state is usual. Life-long medication is needed. Myxedema coma can result in death.

Myxedema coma, the most severe form of hypothyroidism, is rare. It may be caused by an infection, illness, exposure to cold, or certain medications in an individual with untreated hypothyroidism. Symptoms and signs of myxedema coma include unresponsiveness, decreased breathing, low blood pressure, low blood sugar, and below normal temperature.

Other complications are heart disease, increased risk of infection, infertility, and miscarriage.

Call your health care provider if signs of hypothyroidism (or myxedema) are present.

Call your health care provider if chest pain or rapid heart beat occur, infection occurs, symptoms worsen or do not improve with treatment, or new symptoms develop.