Effects of amiodarone on thyroid function in humans

Conference · Wed May 01 00:00:00 EDT 1985 · J. Nucl. Med.; (United States)

OSTI ID:6857696

Zaninovich, A A; Bosco, S; Contreras, L; El Tamer, E; Chiozza, M; Fernandez Pol, J A

The present work studies the effects of the anti-arrhythmic drug amiodarone on thyroidal release slopes (TRS) and peripheral kinetics of /sup 125/I-thyroxine (/sup 125/I-T/sub 4/) and /sup 125/I-triiodothyronine (/sup 125/I-T/sub 3/) during chronic (200-800 mg/day, 2-5 years) or acute (400 mg/day, 5-8 days) treatment with amiodarone. Each patient received a tracer does of /sup 125/I-T/sub 4/ or /sup 125/I-T/sub 3/ iv. TRS were derived from daily plasma ratios of /sup 127/I-T4//sup 125/I-T4 and /sup 127/I-T3//sup 125/I-T3. Double antibody radioimmunoassay techniques were employed to measure serum T4, T3, reverse T3 and thyrotropin (TSH). In the /sup 125/I-T4 studies, 8 chronically-treated patients had a mean TRS value of 0.063 +- 0.033 (SD) versus 0.110 +- 0.030 in controls (NS). Fractional T4 turnover (k) was 70% metabolic clearance rate (MCR) 80% and disposal rate (DS) 79% (NS) of the respective value in control subjects. The acute studies in 5 normal subjects showed no changes with amiodarone. In the /sup 125/I-T3 studies chronic patients had a decreased TRS, k MCR and DR whereas the acute studies showed similar, significant changes during amiodarone treatment. Serum T4 and reverse T3 were significantly elevated serum T3 was decreased and serum TSH was non-significantly increased. The authors conclude that despite the supranormal serum T4 and TSH, amiodarone appeared to depress thyroidal function and to block the thyroid gland response to a peripheral decrease in T4 conversion to T3.

• Research Organization: Nuclear Medicine Center, Hosp. de Clinicas, Univ. of Buenos Aires
• OSTI ID: 6857696
• Report Number(s): CONF-850611-
• Journal Information: J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 26:5; ISSN JNMEA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
BIOCHEMICAL REACTION KINETICS
BIOCHEMISTRY
BIOLOGICAL FUNCTIONS
BODY
CARBOXYLIC ACIDS
CHEMISTRY
DRUGS
ENDOCRINE GLANDS
FUNCTIONS
GLANDS
HORMONES
IODINE ISOTOPES
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LABELLING
METABOLISM
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY HORMONES
RADIOPHARMACEUTICALS
REACTION KINETICS
RESPONSE FUNCTIONS
THYROID
THYROID HORMONES
THYROXINE
TSH