The pharmacodynamic equivalence of levothyroxine and liothyronine: a randomized, double blind, cross-over study in thyroidectomized patients.

Author(s): Celi FS, Zemskova M, Linderman JD, Babar NI, Skarulis MC, Csako G, Wesley R, Costello R, Penzak SR, Pucino F.

Affiliation(s): Clinical Endocrinology Branch, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Building 10, CRC, RM 6-3940, 10 Center Drive, MSC 1613, Bethesda, MD 20892-1613, USA. fc93a@nih.gov

Publication date & source: 2010, Clin Endocrinol (Oxf). , 72(5):709-15

CONTEXT: The substitution of liothyronine (L-T3) for levothyroxine (L-T4) is commonly employed during thyroid hormone (TH) withdrawal in preparation for diagnostic and therapeutic interventions on thyroid cancer patients. Presently, only limited data are available on the L-T3 for L-T4 therapeutic substitution. Objective To characterize the pharmcodynamic equivalence of L-T3 and L-T4. DESIGN: Randomized, double-blind, cross-over intervention study. SETTING: NIH clinical center. PATIENTS: Ten thyroidectomized patients. INTERVENTIONS: Study participants were treated with L-T3 or L-T4 with a target TSH >or= 0.5