[Adequate restitution in primary hypothyroidism depending on levothyroxine formulations].

Background: The prevalence of primary hypothyroidism (PH) is around 3.8%-4.6% in general population. Out of patients under treatment with levothyroxine, approximately 40% show altered levels of thyroid-stimulating hormone (TSH).

Objective: To determine the prevalence of euthyroid sick syndrome in patients under treatment for PH in two local clinics, considering that the number of formulations of levothyroxine could be a contributing factor to the inadequate restitution.

Methods: Descriptive, comparative cohort conducted with PH patients who were treated with a stable dose of levothyroxine for at least six months. Patients treated with mixtures of liothyronine/levothyroxine, with postsurgical hypothyroidism, pregnant, breastfeeding or mentally ill were discarded. Medical clinic 1 was a public center that had only access to levothyroxine of 100 µg, and medical clinic 2 was a private clinic with access to 25, 50, 75 and 100 µg levothyroxine formulations.

Results: A total of 350 patients were evaluated. 190 patients were obtained at clinic 1, and 160 patients at clinic 2. At clinic 1, only 63% received the appropriate dose, while at clinic 2, 75% were medicated with the correct dose (p = 0.033).

Conclusion: In the public center, 39% of patients did not receive appropriate dose of levothyroxine; however, in the private clinic, which had more drug formulations, the percentage of patients lowered to 25%. Therefore, the number of formulations could be a factor for the risk of inadequate restitution.