title: N-acetylcysteine administration prevents nonthyroidal illness syndrome in patients with acute myocardial infarction: a randomized clinical trial.
abstract: BACKGROUND
  The acute phase of the nonthyroidal illness syndrome (NTIS) is characterized by low T3 and high rT3 levels, affecting up to 75% of critically ill patients. Oxidative stress has been implicated as a causative factor of the disturbed peripheral thyroid hormone metabolism.
  
  
  OBJECTIVE
  The objective of the study was to investigate whether N-acetylcysteine (NAC), a potent intracellular antioxidant, can prevent NTIS in patients with acute myocardial infarction.
  
  
  METHODS
  This was a randomized, multicenter clinical trial.
  
  
  METHODS
  Consecutive patients admitted to the emergency and intensive care units of two tertiary hospitals in southern Brazil were recruited. Patients and intervention included 67 patients were randomized to receive NAC or placebo during 48 hours. Baseline characteristics and blood samples for thyroid hormones and oxidative parameters were collected.
  
  
  RESULTS
  Variation of serum T3 and rT3 levels was measured.
  
  
  RESULTS
  Baseline characteristics were similar between groups (all P > .05). T3 levels decreased in the placebo group at 12 hours of follow-up (P = .002) but not in NAC-treated patients (P = .10). Baseline rT3 levels were elevated in both groups and decreased over the initial 48 hours in the NAC-treated patients (P = .003) but not in the control group (P = .75). The free T4 and TSH levels were virtually identical between the groups throughout the study period (P > .05). Measurement of total antioxidant status and total carbonyl content demonstrated that oxidative balance was deranged in acute myocardial infarction patients, whereas NAC corrected these alterations (P < .001).
  
  
  CONCLUSIONS
  NAC administration prevents the derangement in thyroid hormone concentrations commonly occurring in the acute phase of acute myocardial infarction, indicating that oxidative stress is involved in the NTIS pathophysiology.
authors.affiliation: Thyroid Unit (J.V., S.M.W., B.D.S., A.L.M.), Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, CEP 90620-000, Porto Alegre, RS, Brasil; Instituto de Cardiologia do RS/Fundação Universitária de Cardiologia (R.S.L., A.M.); and Division of Endocrinology, Diabetes, and Hypertension (P.R.L.), Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Josi
authors.initials: J
authors.lastname: Vidart
authors.forename: Simone Magagnin
authors.initials: SM
authors.lastname: Wajner
authors.forename: Rogério Sarmento
authors.initials: RS
authors.lastname: Leite
authors.forename: André
authors.initials: A
authors.lastname: Manica
authors.forename: Beatriz D
authors.initials: BD
authors.lastname: Schaan
authors.forename: P Reed
authors.initials: PR
authors.lastname: Larsen
authors.forename: Ana Luiza
authors.initials: AL
authors.lastname: Maia
mesh_terms: D000111:Acetylcysteine / Q000009:adverse effects / Q000627:therapeutic use*; D000208:Acute Disease; D000210:Acute-Phase Reaction; D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications*; D010902:Pituitary Gland / Q000187:drug effects; D011446:Prospective Studies; D013961:Thyroid Gland / Q000187:drug effects; D013963:Thyroid Hormones / Q000097:blood; D016896:Treatment Outcome
chemical_list: D000975:Antioxidants; D013963:Thyroid Hormones; D000111:Acetylcysteine