Alterations in pituitary-thyroid axis function among opioid-dependent subjects after acute and protracted abstinence.

The aim of the present study was to investigate the changes in the pituitary-thyroid axis (PTA) and the time course of the hormonal alterations in subjects with opioid dependence after abstinence. Blood samples from in-patients with opioid dependence and age- and sex-matched healthy controls were collected. The severity of opioid abuse and of withdrawal symptoms was assessed. Results were compared between patients with opioid dependence (n = 30) and healthy controls (n = 30). We found that free triiodothyronine and free thyroxine levels were comparable with healthy controls while thyroid-stimulating hormone (TSH) was lower in patients in acute opioid abstinence period. Also, TSH levels in patients remained lower than controls after 30 days of abstinence. These results indicate that PTA function is altered in opioid-dependent subjects. These data highlight the importance of screening the thyroid function for individuals with chronic opioid dependence.