Hypothyroidism - Treatment

Some patients with persistent symptoms may benefit from triiodothyronine (T3), the other important thyroid hormone. In such cases, either a combination of a lower-dose of thyroxine with a small amount of T3 or natural desiccated Armour thyroid hormone, which contains T3, may be helpful.

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There is the possibility that patients with an autoimmune thyroid condition may have persistent symptoms because of the inflammatory response that underlies this condition. This immune response can cause feelings of fatigue, vague aches and pains, and other symptoms that are similar to hypothyroidism itself. Little research has been conducted on this theory, however.

Side Effects of Under-Dosing. If the levothyroxine dose is not sufficient to restore normal thyroid levels, or if the patient frequently forgets to take the medication, the patient may continue to experience symptoms of hypothyroidism. Even mild hypothyroidism without any symptoms can eventually lead to an increase in cholesterol levels. In one 2000 study, 40% of people taking thyroid medication still had abnormal levels of TSH. To avoid these problems, patients should take the proper dosage of levothyroxine as prescribed and have regular check-ups that include measurement of blood TSH.

Side Effects of Over-dosing: Thyrotoxicosis. Over-dosing can cause thyrotoxicosis, or the symptoms of hyperthyroidism. A patient with too much thyroid hormone in the blood is at an increased risk for abnormal heart rhythms, rapid heartbeat, congestive heart failure, and possibly a heart attack if the patient has underlying heart disease. Excess thyroid hormone is particularly dangerous in newborns, and their drug levels must be carefully monitored to avoid brain damage.

Side Effects of Long-Term Treatment. Patients with hypothyroidism usually receive lifelong levothyroxine therapy. There has been some concern that long-term use will increase the risk of osteoporosis, as suppression therapy does. Studies indicate that postmenopausal women who are taking long-term normal replacement thyroxine have no out-of-the-ordinary risk for osteoporosis.

Suppressive Thyroid Therapy

Suppressive thyroid therapy involves taking levothyroxine in doses that are high enough to block the production of natural TSH but too low to cause hyperthyroid symptoms. It may used for patients with large goiters or thyroid cancer.

Suppressive thyroid therapy places patients, particularly postmenopausal women, at risk for accelerated osteoporosis, a disease that reduces bone mass and increases risk of fractures. Some researchers suggest, however, that such bone loss is too slight to pose any significant risk for fracture. Furthermore, the cholesterol-lowering benefits of suppressive therapy outweigh this small risk. A small study found that premenopausal women taking suppressive therapy for more than 10 years were also at increased risk of bone loss by the time they reach menopause, although more research is needed to confirm this.

Bone density loss can be reduced or avoided by taking no higher a dose of thyroxine than necessary to restore normal thyroid function. In any case, doses of T4 must be continuously and carefully tailored in all patients to avoid adverse effects on the heart. (Of note was a 2000 study reporting that radioactive iodine may be an effective alternative for patients with benign goiters and may have fewer side effects.)

A number of medications are also available that can help preserve bone in postmenopausal women. Note, however, that women on hormone replacement therapy may need to increase their dose of thyroid hormone.