Initial response of young people with thyrotoxicosis to block and replace or dose titration thionamide.

Objective: Patients with thyrotoxicosis are treated with anti-thyroid drug (ATD) using block and replace (BR) or a smaller, titrated dose of ATD (dose titration, DT).

Design: A multi-centre, phase III, open-label trial of newly diagnosed paediatric thyrotoxicosis patients randomised to BR/DT. We compared the biochemical response to BR/DT in the first 6 months of therapy.

Randomised trial of block and replace vs dose titration thionamide in young people with thyrotoxicosis.

Objective: First-line treatment of thyrotoxicosis in young people is thionamide anti-thyroid drug (ATD) in a blocking dose with levothyroxine replacement (block and replace, BR) or in a smaller dose tailored to render the patient euthyroid (dose titration, DT). Our objective was to determine which regimen provides more stable biochemical control.

Design: A multi-centre phase III, open-label randomised trial comparing BR with DT in patients aged 2-17 years with newly diagnosed thyrotoxicosis at 15 UK centres.