title: Treatment of hypothyroidism with levothyroxine or a combination of levothyroxine plus L-triiodothyronine.
abstract: At present, the drug of choice for the treatment of hypothyroidism is levothyroxine sodium, even though the thyroid gland secretes both thyroxine and 3',3,5-triiodothyronine; the latter is the more active of the two at the cellular level because of its higher affinity for the nuclear thyroid hormone receptors. To date, combined levothyroxine plus liothyronine treatment for hypothyroidism has been evaluated in 15 clinical trials in humans. In two studies, combined therapy seemed to have beneficial effects on mood, quality of life, and psychometric performance of patients, compared with levothyroxine alone; in some of these studies, the patients preferred levothyroxine plus liothyronine combinations. This preference should be balanced against the possibility of adverse events resulting from the addition of liothyronine to levothyroxine. Until clear advantages of levothyroxine plus liothyronine are demonstrated, the administration of levothyroxine alone should remain the treatment of choice for replacement therapy of hypothyroidism.
authors.affiliation: Department of Endocrinology & Nutrition, Hospital Universitario Ramón y Cajal & Instituto Ramón y Cajal de Investigación Sanitaria IRYCYS, Madrid, Spain; Universidad de Alcalá & Centro de Investigación Biomédica en Red Diabetes y Enfermedades Metabólicas Asociadas CIBERDEM, Madrid, Spain. Electronic address: hectorfrancisco.escobar@salud.madrid.org.
authors.forename: Héctor F
authors.initials: HF
authors.lastname: Escobar-Morreale
authors.affiliation: Department of Endocrinology & Nutrition, Hospital Universitario Ramón y Cajal & Instituto Ramón y Cajal de Investigación Sanitaria IRYCYS, Madrid, Spain; Centro de Investigación Biomédica en Red Diabetes y Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Madrid, Spain.
authors.forename: José I
authors.initials: JI
authors.lastname: Botella-Carretero
authors.affiliation: Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas y Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Morreale de Escobar
mesh_terms: D004359:Drug Therapy, Combination; D020249:Hormone Replacement Therapy; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy*; D013974:Thyroxine / Q000627:therapeutic use*; D016896:Treatment Outcome; D014284:Triiodothyronine / Q000627:therapeutic use*
chemical_list: D014284:Triiodothyronine; D013974:Thyroxine
keywords: combined therapy; hypothyroidism; levothyroxine; liothyronine; replacement