title: Sustained control of Graves' hyperthyroidism during long-term low-dose antithyroid drug therapy of patients with severe Graves' orbitopathy.
abstract: BACKGROUND
  Patients with severe Graves' orbitopathy often have hyperthyroidism that is difficult to treat and a high proportion of patients experience relapse of hyperthyroidism after a course of antithyroid drug (ATD) therapy of fixed duration. The aim of the study was to evaluate the feasibility of prolonged low-dose ATD therapy for attaining stable euthyroidism in patients with severe Graves' orbitopathy and hyperthyroidism.
  
  
  METHODS
  We performed retrospective analyses of data collected during observation of a cohort of patients (n = 108) treated for severe Graves' orbitopathy and for hyperthyroidism using partial block with low-dose thionamide + replacement with levothyroxine (L-T4) for >2 years. The study was performed at a university hospital referral center for patients with severe Graves' orbitopathy.
  
  
  RESULTS
  The median duration of thionamide therapy was 80 months (25-75 percentiles: 55-115 months); 101 patients received methimazole (median: 5 mg/day) without side effects during prolonged therapy, and 7 propylthiouracil (median: 200 mg/day); median L-T4 dose was 0.1 mg/day. Ninety percent of patients remained euthyroid throughout the period of therapy, and 65% of them had thyroid stimulating hormone (TSH) receptor antibodies in serum within the assay reference interval at the last observation. Only four (3.7%) developed episodes of hyperthyroidism during stable therapy, and 94% had serum TSH within 0.1-4.0 mU/L at the last observation. One patient developed reversible cutaneous vasculitis after 6 years of propylthiouracil therapy.
  
  
  CONCLUSIONS
  Prolonged partial block plus replacement therapy with low-dose ATD + L-T4 keeps the majority of patients with severe Graves' orbitopathy and hyperthyroidism stable and euthyroid.
authors.affiliation: Department of Endocrinology, Aarhus University Hospital, Aalborg, Denmark. peter.laurberg@rn.dk
authors.forename: Peter
authors.initials: P
authors.lastname: Laurberg
authors.forename: Dalia C
authors.initials: DC
authors.lastname: Berman
authors.forename: Stig
authors.initials: S
authors.lastname: Andersen
authors.forename: Inge
authors.initials: I
authors.lastname: Bülow Pedersen
mesh_terms: D000328:Adult; D013956:Antithyroid Agents / Q000008:administration & dosage* / Q000009:adverse effects; D015415:Biomarkers / Q000097:blood; D003718:Denmark; D004334:Drug Administration Schedule; D005240:Feasibility Studies; D005260:Female; D006111:Graves Disease / Q000175:diagnosis / Q000188:drug therapy* / Q000276:immunology; D049970:Graves Ophthalmopathy / Q000175:diagnosis / Q000188:drug therapy* / Q000276:immunology; D020249:Hormone Replacement Therapy; D006785:Hospitals, University; D006801:Humans; D018828:Immunoglobulins, Thyroid-Stimulating / Q000097:blood; D008297:Male; D008713:Methimazole / Q000008:administration & dosage* / Q000009:adverse effects; D008875:Middle Aged; D011441:Propylthiouracil / Q000008:administration & dosage* / Q000009:adverse effects; D012008:Recurrence; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013974:Thyroxine / Q000008:administration & dosage; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D013956:Antithyroid Agents; D015415:Biomarkers; D018828:Immunoglobulins, Thyroid-Stimulating; C094372:thyrotropin-binding inhibitory immunoglobulin; D008713:Methimazole; D011441:Propylthiouracil; D013974:Thyroxine