Little has been published on the long-term management of thyrotoxicosis with antithyroid drugs (ATDs). We analysed 376 thyrotoxic subjects on the Morriston database since 2002. 170 had Graves disease, 181 toxic multinodular goitre (TMNG); in 25 the diagnosis was not recorded. When euthyroid subjects were requested to have annual thyroid function testing 42 (11%) had died. 111(30%) did not have TFTs done in last two years. 135 gravess cases were given ATDs which were discontinued after euthyroidism achieved in 90; relapse occurred in 42 after a median time of 15 months. 72 subjects (including those restarted after relapse) have been on long term ATDs for median of 48 months with normal TSH. 145 TMNG patients were given ATDs; 39 discontinued after achieving euthyroidism. Relapse occurred in 26 after a median time of 8 months. 129 have been on long term ATDs for median of 60.9 months with normal TSH Summary: Relapse after discontinuation of ATDS occurs in 50% of Graves patients and the majority of subjects with TMNG. However, low dose ATDs maintain euthyroidism in almost all subjects regardless of aetiology.
Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.
Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.