Antithyroid Drugs During Radioiodine Therapy

February 2, 2006 updated by: Odense University Hospital

The Influence of Continuous Treatment With Antithyroid Drugs on the Effect of Radioiodine in Patients With Hyperthyroidism

Background: The use of radioactive iodine (131I) therapy as the definite cure of hyperthyroidism is widespread. According to a survey on the management of Graves' disease, thirty per cent of physicians prefer to render their patients euthyroid by antithyroid drugs (ATD) prior to 131I therapy. This strategy is presumably chosen to avoid 131I induced 'thyroid storm', which, however, is rarely encountered. Several studies have consistently shown that patients who are treated with ATD prior to 131I therapy have an increased risk of treatment failure. Mostly, patients with Graves' disease have been studied, while other studies were addressed also toxic nodular goiter. Thus, it is generally accepted that ATD have 'radioprotective' properties, although this view is almost exclusively based on retrospective data and is still under debate (13). Indeed, this dogma was recently challenged by two randomized trials in Graves' disease, none of which showed such an adverse effect of methimazole pretreatment. It cannot be excluded that the earlier results may have been under influence of selection bias, a source of error almost unavoidable in retrospective studies. Whether ATD is radioprotective also when used in the post 131I period has also been debated. In the early period 131I therapy following a transient rise in the thyroid hormones is seen which may give rise to discomfort in some patients. The continuous use of ATD during 131I therapy leads to more stable levels of the thyroid hormones. By resuming ATD following 131I therapy, euthyroidism can usually be maintained until the destructive effect of 131I ensues. Nevertheless, many physicians prefer not to resume ATD, probably due to reports supporting that such a strategy reduces the cure rate. Parallel to the issue of ATD pretreatment, the evidence is based on retrospective studies and the ideal set-up should be reconsidered. To underscore the importance of performing randomized trials we showed recently that resumption of methimazole seven days after 131I therapy had no influence on the final outcome.

Aim: To clarify by a randomized trial whether continuous use of methimazole during radioiodine therapy influences the final outcome of this therapy, in a comparison with a regime in which methimazole as mono-therapy is discontinued 8 days before radioiodine.

Patients and Methods: 80 consecutive patients suffering from recurrent Graves' disease or a toxic nodular goiter are included. All patients are rendered euthyroid by methimazole (MMI) and randomized either to stop MMI eight days before 131I or to continue MMI until four weeks after 131I. Calculation of the 131I activity (max. 600 MBq) includes an assessment of the 131I half-life and the thyroid volume. Patients are followed for one year with close monitoring of the thyroid function.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment

80

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Denmark
    • Funen
      • Odense, Funen, Denmark, 5000
        • Department of Endocrinology, Odense University Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years to 83 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Hyperthyroid patients going to be treated with radioiodine either due to recurrent Graves' disease or toxic nodular goiter.

Exclusion Criteria:

  • Age < 18 yrs.
  • Allergy to anti-thyroid drugs
  • Substernal or large (> 100ml) goiter
  • Severe endocrine ophthalmopathy
  • Pregnancy or lactation
  • Suspicion of thyroid malignancy
  • Unsafe contraconception
  • Physical or mental condition that hinders corporation

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Thyroid function after one year of follow-up

Secondary Outcome Measures

Outcome Measure
Thyroid radioiodine 131I uptake
Thyroid volume after one year of follow-up

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Odense University Hospital

Investigators

  • Principal Investigator: Steen J Bonnema, MD, PhD, Odense University Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

January 1, 2003

Study Completion

December 1, 2004

Study Registration Dates

First Submitted

September 6, 2005

First Submitted That Met QC Criteria

September 6, 2005

First Posted (Estimate)

September 8, 2005

Study Record Updates

Last Update Posted (Estimate)

February 3, 2006

Last Update Submitted That Met QC Criteria

February 2, 2006

Last Verified

September 1, 2005

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 013

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Graves Disease

Clinical Trials on Methimazole

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Burundi

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

3
Subscribe