Thyroid Research Thyroid Research Archive Hypothyroidism

Thyroxine plus triiodothyronine and thyroxine alone have similar efficacy in patients with hypothyroidism

(March 2004)

The background of the study. Thyroxine (T4) therapy may not restore normal health and well being in patients with hypothyroidism. This study was done to determine if replacing some T4 with triiodothyronine (T3) resulted in improvement in symptoms in both unsatisfied and satisfied patients with hypothyroidism.

How the study was done. The study subjects were 110 patients (101 women) with hypothyroidism who had been taking at least 100 µg of T4 daily (mean dose, 136 µg) for at least two months. At base line, 45 percent felt well and were satisfied with their treatment and 55 percent were not satisfied, because of persistent symptoms such as decreased well-being, fatigue, and weight gain.

The patients were randomly assigned to receive their usual T4 dose or a 50 µg lower dose of T4 plus 10 µg of T3 (in identical capsules) once daily for 10 weeks. The patients then took their usual T4 dose for four weeks, after which they took the opposite treatment for 10 weeks. At base line and at the end of each treatment period, the patients were examined and completed questionnaires, including the Short Form 36 (a general health questionnaire), the General Health Questionnaire (GHQ), which measures psychological dysfunction, the Thyroid Symptom Questionnaire (TSQ), and a satisfaction scale. Cognitive function also was tested.

The results of the study. There were no changes in weight or blood pressure at any time. The mean serum thyrotropin concentration was slightly higher and the mean serum free T4 concentration was lower after T4-plus-T3 treatment. There were no differences in the scores for the Short Form 36, the GHQ, the TSQ, and the satisfaction scale, or the results of the cognitive function tests at the end of the two treatment periods.

The conclusions of the study. The combination of T4 and T3 is no more effective than T4 alone in ameliorating symptoms and improving quality of life in patients with hypothyroidism.

The original article. Walsh JP, Shiels L, Lim EM, Bhagat CI, Ward LC, Stuckey BG, Dhaliwal SS, Chew GT, Bhagat MC, Cussons AJ. Combined thyroxine/liothyronine treatment does not improve well being, quality of life, or cognitive function compared to thyroxine alone: a randomized controlled trial in patients with primary hypothyroidism. J Clin Endocrinol Metab 2003;88:4543-50.