Widespread prescribing of the medication levothyroxine sodium to boost thyroid function in patients with borderline high levels of the thyroid-stimulating hormone thyrotropin (a sign of low thyroid function), might raise the possibility of overtreatment, according to research in the United Kingdom.
Hypothyroidism is one of the most chronic conditions in Western populations, with levothyroxine prescriptions increasing in the U.S., England, and Whales. Peter N. Taylor, M.Sc., M.R.C.P., of the Cardiff University School of Medicine, United Kingdom, and colleagues examined trends in thyrotropin levels before and after levothyroxine therapy.
Researchers found that between 2001 and 2009, the median (midpoint) thyrotropin level at the start of levothyroxine treatment declined from 8.7 to 7.9 mIU/L, with an increase in the odds of having levothyroxine therapy start at a thyrotropin level of 10 mIU/L or less. “In the United Kingdom, 1.6 million individuals are on long-term levothyroxine regimens, most of whom have been prescribed it for primary hypothyroidism. If current practice continues, up to 30 percent of persons receiving levothyroxine therapy may have been prescribed it without an accepted indication and with the potential for net harm if they develop even a low thyrotropin level,” researchers were quoted as saying.