Update on therapy for underactive thyroid gland

Millions of Americans take Synthroid or its generic equivalent each day to treat an underactive thyroid gland, but some still complain they don’t feel right. They may be sluggish, forgetful or put on extra pounds.

Synthroid, also called levothyroxine, is a synthetic form of the thyroid hormone thyroxine, called T4. The body converts it into an active form of thyroid hormone called triiodothyronine, or T3. Some doctors have been prescribing lower doses of Synthroid and adding synthetic T3, called liothyronine, to improve patients’ symptoms, even though little scientific data backs up the practice.

Now, a study of 46 patients, ages 24 to 65, treated for four months with either Synthroid alone or the dual therapy, found no benefit to the combination.

In the study, which appears in the current issue of the Journal of the American Medical Assn., researchers from the National Naval Medical Center in Bethesda, Md., reported that combined therapy didn’t help patients lose weight, improve their cholesterol or think more clearly.

-- Jane E. Allen