To the Editor: Dr Clyde and colleagues1 concluded that treatment of primary hypothyroidism with combination levothyroxine plus liothyronine was not superior to levothyroxine alone in terms of body weight, serum lipid levels, hypothyroid symptoms, or cognitive performance. Although Clyde et al recommend that patients should be treated with synthetic thyroid on the basis of cost, natural desiccated thyroid is considerably less expensive. Thus, perhaps this would be the most rational treatment choice.
1. Clyde PW, Harari AE, Getka EJ, Shakir KMM. Combined
levothyroxine plus liothyronine compared with levothyroxine alone in primary
hypothyroidism: a randomized controlled trial. JAMA.
Letters Section Editor: Stephen J. Lurie, MD, PhD, Senior Editor.
Synthetic Thyroxine vs Dessicated Thyroid—Reply
In Reply: Dr Lichten emphasizes the importance of considering costs when choosing between different medications with similar therapeutic efficacies. However, the objective of our study was to investigate the efficacy of levothyroxine plus liothyronine compared with levothyroxine monotherapy in primary hypothyroidism. We did not assess the efficacy of desiccated thyroid or the cost effectiveness of different thyroid hormone preparations.
If administered as
in our study, liothyronine (Cytomel, King Pharmaceuticals, St
Louis, Mo) 7.5 µg twice daily, along with levothyroxine, the cost
of the liothyronine component alone would be over $100 for a
90-day supply.1 The brand of levothyroxine (Synthroid,
Abbott Laboratories, Abbott Park, Ill) we used was simply the
brand carried on our institution's pharmacy formulary. To provide
thyroid hormone therapy in a similar manner to that used in our
study, desiccated thyroid would need to be taken twice daily,
since desiccated thyroid does not provide a slow-release form