Thyroid hormones in obese patients treated with dexfenfluramine

Abstract

It has been reported that thyroid function tests change during calorie-restricted diet treatment. However, the results are often conflicting. The present study was carried out to evaluate the effect of dexfenfluramine on thyroid function in 40 obese women. Patients were divided into two groups: the first group (group 1) (n = 20) received dexfenfluramine 15 mg twice a day plus calorie-restricted diet and the second group (group 2) (n = 20) had only calorie-restricted diet. Both groups were similar in respect to age. The study period lasted three months. Mean basal levels of free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) revealed no significant differences between the two groups (p > 0.05). Patients receiving dexfenfluramine had low FT3 levels when compared with group 2 (p < 0.01). Thyroid hormone levels showed no significant changes in group 2 (p > 0.05). However, the levels of FT3 were decreased significantly in group 1 (p < 0.05). In conclusion, our study suggested that dexfenfluramine with its anorexigenic feature and other unknown effects causes reduction in FT3 levels in obese patients.