Higher-dose methimazole helps GD patients with severe thyrotoxicosis reach euthyroid status

Methimazole given in a large dose allows individuals with severe thyrotoxicosis from Graves’ disease (GD) to achieve euthyroid status as fast as other GD patients, according to a study.

“However, these patients have more lability in thyroid control and may benefit from more frequent monitoring,” the authors said.

Initial disease severity correlated with percentage dose reduction of methimazole per encounter (p=0.012) and the proportion of hypothyroid encounters (p=0.0101). Initial disease severity showed no significant association with the proportion of hyperthyroid encounters (p=0.088), methimazole dose after 180 days (p=0.222), or time to first encounter with euthyroid status.

Age and sex did not significantly contribute to changes in dose or biochemical thyroid status.

“After 6 months, severity of initial thyrotoxicosis was not associated with methimazole dose,” the authors said.

This retrospective longitudinal cohort study was conducted at a single tertiary medical centre from 2018 to 2024. A total of 152 patients with GD aged ≥18 years were included in the analysis, which focused on the association of initial disease severity, age, and sex with average decrease in methimazole dose per encounter, biochemical thyroid status per encounter, time until first euthyroid encounter, and dose of methimazole after 180 days of treatment.

“GD is the most common cause of thyrotoxicosis,” the authors said. “Medical therapy with methimazole is the most common way to treat GD, but it has a narrow and dynamic therapeutic index, requiring frequent monitoring for titration.”