Levothyroxine Antithyroid Drug Combination Therapy Efficacy Of Graves Disease

Background and Objective:Graves disease(GD) is a common autoimmune disorder of human beings.The most frequent therapeutic policy to achieve euthyroidism in GD is to use antithyroid drug(ATD) over a period of several months or years,but people treated with ATD have a roughly40%chance of long-term remission.Putting the thyroid at rest by suppression of thyrotropin(TSH) with exogenous levo-thyroxine(L-T4) in addition to ATD medication was thought to be beneficial and have a improved remission rates.We have conducted a study in patients with GD and compared the outcome of treatment with methimazole with that of the combination of methimazole(MMI) plus L-T4,and investigate the effect of L-T4in the therapy of GD.Method:This is a randomized,open,multicentered study,158patients with newly diagnosed,previously untreated GD from nine study centers in Jiangsu province were enrolled in the study.Patients were randomly assigned into two groups:group A and group B.Initially all patients were treated with40mg MMI daily for one month.After an average of4to6weeks when hyperthyroidism was controlled,the dosage of MMI in both group was dropped to20mg/day,and75-150ug/day L-T4was added in group B.At the end of week16,the dosage of MMI in group B was adjusted to10mg/day and the dosage of L-T4remained unchanged;and from week48,patients in group B began to take MMI5mg/day and L-T450ug/day;by the end of52week, both drugs were discontinued.In group A,the dosage of MMI was adjusted in order to maintain a normal thyroid functioned condition.During the study,serum T3,T4,FT3,FT4,TSH and serum TRAb concentration were recorded every month,while echography recorded once at both the beginning and the end.Results:The general conditions of the two group were similar before treatment.By the end of the twelfth month,the mean values of thyroid function were not differ significantly between group:FT3.(4.9±1.2vs.5.3±1.1pmol/L),FT4:(14.0±2.9vs.18.1±8.5pmol/L), T3:(1.8±0.3vs.1.9±0.4nmol/L), T4:(101.2±25.8vs.106.3±21.2nmol/L), TSH:(0.6±1.0vs.1.1±1.3mIU/L).After12months of ATD treatment,the serum concentration of TRAb in group A was higher than that in group B:(5.9±1.8vs.2.8±1.9mIU/L),t=0.403, P=0.03.And by the time of drug discontinuation,the mean thyroid volume of group A was greater than that of group B:26.4±4.2vs.21.8±4.4ml.The difference has statistically significant.Conclusion:After twelve months of treatment,the value of serum TRAb and thyroid volume in patients given combination of MMI and L-T4were lower than those of patients taking MMI alone,so we infer that combination of MMI and L-T4may be beneficial for the remission of GD.