title: An audit of amiodarone-induced thyrotoxicosis--do anti-thyroid drugs alone provide adequate treatment?
abstract: BACKGROUND
  Amiodarone is a widely used anti-arrhythmic drug. A common long-term complication is amiodarone-induced thyrotoxicosis (AIT). We examined retrospectively the efficacy of anti-thyroid drugs with or without prednisolone and the role of surgical thyroidectomy in the treatment of AIT in a single centre, in an iodine-replete region of Australia.
  
  
  METHODS
  A retrospective audit of patients with AIT was performed between 2002-2012 at this centre. Twenty-seven patients, mean age 60.9 ± 2.3 years were identified. Medical therapy (anti-thyroid drugs, prednisolone) was commenced according to the treating endocrinologist. The main outcomes were time to euthyroidism and number proceeding to thyroidectomy.
  
  
  RESULTS
  Of 11 patients commenced on anti-thyroid drugs alone, seven (64%) required the addition of prednisolone. Baseline free T4 was significantly higher in those ultimately treated with prednisolone (58.4 ± 6.3pmol/L) versus those not (31.7 ± 3.4pmol/L, P<0.05). Although similar results were seen with free T3, the difference was not significant (P=0.06). In patients with baseline free T4 <30pmol/L, 75% (3/4) achieved euthyroidism without prednisolone. Neither the use of prednisolone nor continuation of amiodarone significantly influenced time to euthyroidism. Eleven patients (41%) proceeded to surgical thyroidectomy, which was undertaken by an experienced surgical team without significant complications and no mortality.
  
  
  CONCLUSIONS
  Patients with AIT generally required glucocorticoids. Mild disease (free T4 <30pmol/L) may be successfully treated with anti-thyroid drugs alone. Surgical thyroidectomy is a safe and effective treatment for those refractive to medical therapy.
authors.affiliation: Department of Diabetes and Endocrinology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.
authors.forename: Nadia
authors.initials: N
authors.lastname: Patel
authors.affiliation: Department of Diabetes and Endocrinology, Princess Alexandra Hospital, Brisbane, Queensland, Australia; School of Medicine, The University of Queensland, Brisbane, Australia.
authors.forename: Warrick J
authors.initials: WJ
authors.lastname: Inder
authors.affiliation: Department of Diabetes and Endocrinology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.
authors.forename: Clair
authors.initials: C
authors.lastname: Sullivan
authors.affiliation: School of Medicine, The University of Queensland, Brisbane, Australia; Department of Cardiology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.
authors.forename: Gerald
authors.initials: G
authors.lastname: Kaye
mesh_terms: D000638:Amiodarone / Q000008:administration & dosage / Q000009:adverse effects*; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000009:adverse effects*; D013956:Antithyroid Agents / Q000008:administration & dosage*; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage; D006801:Humans; D008485:Medical Audit; D008875:Middle Aged; D011239:Prednisolone / Q000008:administration & dosage; D011793:Queensland; D012189:Retrospective Studies; D013971:Thyrotoxicosis / Q000139:chemically induced* / Q000628:therapy*
chemical_list: D000889:Anti-Arrhythmia Agents; D013956:Antithyroid Agents; D005938:Glucocorticoids; D011239:Prednisolone; D000638:Amiodarone
keywords: Amiodarone; Arrhythmias; Prednisolone; Thyroidectomy; Thyrotoxicosis; Ventricular tachycardia