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  • Poster presentation
  • Open Access

Block & replacement regimen is more cost effective than titration regimen in treating thyrotoxicosis in children, without more harm

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International Journal of Pediatric Endocrinology20152015 (Suppl 1) :P105

  • Published:


  • Thyrotoxicosis
  • Clinic Visit
  • Remission Rate
  • Drug Cost
  • Significant Adverse Effect


The first line treatment of thyrotoxicosis in our unit is anti-thyroid medication for 2 years – longer if unstable control. Since 2010, we changed the anti-thyroid treatment protocol from block and replacement (B&R) to titration regimen (TIT), after the Cochrane review showed that B&R was associated with similar remission rate but more frequent adverse effects than TIT. We aimed at comparing these 2 regimens in our pediatric patients.


Patients who received TIT from 2010 to 2014 for relapse of thyrotoxicosis and previously had at least 1 full course of B&R were reviewed. Those who had less than 2 years of TIT, either because they received surgery or radioactive iodine within 2 years, or they have not yet finished the course, were excluded from analysis.

The course of B&R versus TIT was compared within each individual. For those who had previously multiple courses of B&R, the latest course was used for analysis.

Occurrence of adverse drug side effects, length of the anti-thyroid treatment course, number of clinic visits and thyroid function tests during the course, and frequency of abnormal free thyroxine levels were reviewed and analyzed by paired t-test.


27 patients, who received B&R previously, were put on TIT for relapse of thyrotoxicosis after 2010. 17 patients were excluded from the analysis as they were on TIT for less than 2 years, 9 of them had surgery or radioactive iodine within 2 years after starting TIT.

Among the 10 patients (4 males, 6 females, age 8-16 years) analysed, no significant drug side effect was experienced during both treatment periods. While on TIT, patients required longer duration of treatment (average 23% longer, p=0.005) with more clinic visits (average 50% increase, p=0.003) and thyroid function tests (average 85% increase, p=0.002).

They needed more frequent clinic visits (average 22% increase, p=0.04) and thyroid function tests (average 50% increase, p=0.007) per year. They had higher number of abnormal free thyroxine levels per year (average 28% more frequent, p=0.023). The percentage of abnormal free thyroxine levels dropped insignificantly by 2.6% (p=0.645).

The estimated drug cost for 2 year’s B&R was ~397 HKD (51.2 USD / 54.6 AUD), while 2 years’ TIT cost ~177 HKD (22.8 USD / 24.3 AUD).


Both B&R and TIT are safe without significant adverse effect. B&R seems more cost effective with shorter treatment duration and less frequent clinical and biochemical monitoring, even drug cost is slightly higher.

Authors’ Affiliations

Department of Pediatrics & Adolescent Medicine, Queen Mary Hospital, Hong Kong


© Kwok and Cheung; licensee BioMed Central Ltd. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.