title: Treatment of amiodarone-induced thyrotoxicosis type 2: a randomized clinical trial.
abstract: BACKGROUND
  Amiodarone-induced thyrotoxicosis (AIT) type 2 is self-limiting in nature, but most physicians are reluctant to continue amiodarone. When prednisone fails to restore euthyroidism, possibly due to mixed cases of AIT type 1 and 2, perchlorate (ClO(4)) might be useful because ClO(4) reduces the cytotoxic effect of amiodarone on thyrocytes.
  
  
  OBJECTIVE
  Our objectives were to demonstrate the feasibility of continuation of amiodarone in AIT type 2 and to evaluate the usefulness of ClO(4) (given alone or in combination with prednisone) in AIT type 2.
  
  
  METHODS
  A randomized multicenter study was conducted in 10 Dutch hospitals.
  
  
  METHODS
  Patients with AIT type 2 were randomized to receive prednisone 30 mg/d (group A, n = 12), sodium perchlorate 500 mg twice daily (group B, n = 14), or prednisone plus perchlorate (group C, n = 10); all patients continued amiodarone and were also treated with methimazole 30 mg/d. Follow-up was 2 yr.
  
  
  METHODS
  Treatment efficacy (defined as TSH values ≥ 0.4 mU/liter under continuation of amiodarone) and recurrent thyrotoxicosis were evaluated.
  
  
  RESULTS
  Initial therapy was efficacious in 100, 71, and 100% of groups A, B, and C, respectively (P = 0.03). The 29% failures in group B became euthyroid after addition of prednisone. Neither the time to reach TSH of 0.4 mU/liter or higher [8 wk (4-20), 14 wk (4-32), and 12 wk (4-28) in groups A, B, and C respectively] nor the time to reach free T(4) of 25 pmol/liter or below [4 wk (4-20), 12 wk (4-20), and 8 wk (4-20) in groups A, B, and C) were significantly different between groups (values as median with range). Recurrent thyrotoxicosis occurred in 8.3%.
  
  
  CONCLUSIONS
  Euthyroidism was reached despite continuation of amiodarone in all patients. Prednisone remains the preferred treatment modality of AIT type 2, because perchlorate given alone or in combination with prednisone had no better outcomes.
authors: Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam 1105AZ, The Netherlands. s.eskes@sfg.nl
authors: Silvia A
authors: SA
authors: Eskes
authors: Erik
authors: E
authors: Endert
authors: Eric
authors: E
authors: Fliers
authors: Ronald B
authors: RB
authors: Geskus
authors: Robin P F
authors: RP
authors: Dullaart
authors: Thera P
authors: TP
authors: Links
authors: Wilmar M
authors: WM
authors: Wiersinga
mesh_terms: D000328:Adult; D000368:Aged; D000638:Amiodarone / Q000009:adverse effects*; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects; D013956:Antithyroid Agents / Q000009:adverse effects / Q000627:therapeutic use; D052244:Endocrine Disruptors / Q000009:adverse effects / Q000627:therapeutic use; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010472:Perchlorates / Q000009:adverse effects / Q000627:therapeutic use*; D012008:Recurrence; D013960:Thyroid Function Tests; D013971:Thyrotoxicosis / Q000139:chemically induced* / Q000145:classification / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents; D013956:Antithyroid Agents; D052244:Endocrine Disruptors; D010472:Perchlorates; D000638:Amiodarone; C494474:perchlorate