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Effects of N-acetylcysteine on Low T3 Syndrome

This study has been completed.
Hospital de Clinicas de Porto Alegre
Programa de pós-graduação em endocrinologia
Information provided by (Responsible Party):
Josi Vidart, Federal University of Rio Grande do Sul Identifier:
First received: November 25, 2011
Last updated: March 30, 2015
Last verified: March 2015
The propose of this study is to determine whether N-acetylcysteine is effective in reversing the changes in thyroid hormones seen in critical illness, known as the low T3 syndrome.

Condition Intervention Phase
Acute Myocardial Infarction
Euthyroid Sick Syndrome
Ischemic Heart Disease
Drug: N-acetylcysteine
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single Blind (Participant)
Primary Purpose: Treatment
Official Title: Evaluation of the Effects of N-acetylcysteine on Thyroid Hormone Levels in the Low T3 Syndrome

Resource links provided by NLM:

Further study details as provided by Federal University of Rio Grande do Sul:

Primary Outcome Measures:
  • Serum T3 Levels at 48 Hours [ Time Frame: 48 hours ]

Enrollment: 83
Study Start Date: November 2011
Study Completion Date: November 2013
Primary Completion Date: July 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: n-acetylcysteine
intra-venous infusion of 1200 mg of n-acetylcysteine twice a day for 48 hours.
Drug: N-acetylcysteine
in infusion of 1200 mg of n-acetylcysteine twice a day for 48 hours
Other Names:
  • NAC
  • acetylcysteine
No Intervention: no intervention
No intervention

Detailed Description:

The low T3 syndrome or nonthyroidal illness is characterized by low levels of T3, normal or high normal levels of rT3, low or normal levels of T4 and inappropriately normal or low levels of TSH. These changes affect up to 75% of patients and have prognostic implications.

Interleukin-6 (IL6) seems to have a causative role in the pathogenesis of nonthyroidal illness. There is evidence that the reduction in serum T3 was inversely associated with serum IL-6, while the rT3 have a positive association. The mechanism of action of cytokines on the metabolism of thyroid hormones has not been determined and the potential role of cytokines on the deiodases has been the focus of research.

In a cell culture model study, IL-6 was able to suppress the conversion of T4 to T3 by deiodases type 1 and 2 and stimulate the inactivation of T3 by deiodase type 3, a situation similar to nonthyroidal illness. The use of N-acetylcysteine prevented this alterations, been consistent with the hypothesis that IL6 inhibits the function of the deiodases by increasing the oxygen reactive species and by consuming gluthathione or some gluthathione dependent cofactor.

Considering the absence of human studies evaluating the use of N-acetylcysteine in nonthyroidal illness, the aim of this study is to investigate whether NAC has in vivo effect on changes of thyroid hormones.


Ages Eligible for Study:   18 Years to 80 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • diagnosis of acute myocardial infarction with less than 12 hours of evolution
  • reperfusion therapy (primary angioplasty)

Exclusion Criteria:

  • Thyroid disease
  • Chronic renal disease with renal replacement therapy
  • hepatic insufficiency
  • immunosuppression
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Please refer to this study by its identifier: NCT01501110

Hospital de Clínicas de Porto Alegre
Porto Alegre, Rio Grande do Sul, Brazil, 90540001
Instituto de Cardiologia
Porto Alegre, Rio Grande do Sul, Brazil, 90540001
Sponsors and Collaborators
Federal University of Rio Grande do Sul
Hospital de Clinicas de Porto Alegre
Programa de pós-graduação em endocrinologia
Principal Investigator: Josi Vidart Federal University of Rio Grande do Sul
Study Director: Ana maia Federal University of Rio Grande do Sul
  More Information

Additional Information:
Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Josi Vidart, Principal Investigator, Federal University of Rio Grande do Sul Identifier: NCT01501110     History of Changes
Other Study ID Numbers: 110061
Study First Received: November 25, 2011
Results First Received: December 3, 2014
Last Updated: March 30, 2015

Keywords provided by Federal University of Rio Grande do Sul:
Euthyroid Sick Syndrome
low T3 syndrome
oxidative stress
ischemic heart disease

Additional relevant MeSH terms:
Heart Diseases
Myocardial Infarction
Myocardial Ischemia
Coronary Artery Disease
Euthyroid Sick Syndromes
Pathologic Processes
Cardiovascular Diseases
Vascular Diseases
Coronary Disease
Arterial Occlusive Diseases
Thyroid Diseases
Endocrine System Diseases
Antiviral Agents
Anti-Infective Agents
Respiratory System Agents
Free Radical Scavengers
Molecular Mechanisms of Pharmacological Action
Protective Agents
Physiological Effects of Drugs
Antidotes processed this record on May 25, 2017