Liquid levothyroxine improves thyroid control in patients with different hypothyroidism aetiology and variable adherence - case series and review.

Abstract

It is estimated that hypothyroidism treatment may be either suboptimal or excessive in about 32-45% patients treated with L-thyroxine (LT4). There are multiple possible causes of poor control of hypothyroidism, including narrow LT4 therapeutic index, food and drug interactions, comorbidities, and patient non-adherence. Some of these obstacles could possibly be overcome with the novel liquid LT4 formulation. Liquid LT4 reaches maximum blood concentration about 30 minutes faster than the tablet form. Faster pharmacokinetics might lead to more efficient LT4 absorption, as suggested by a recent real-world study in patients with primary and central hypothyroidism. Liquid LT4 treatment led to increased free thyroxine (FT4) and sex hormone binding globulin (SHBG) with decreased low-density lipoprotein (LDL) cholesterol concentration and substantially improved quality of life for the patients. Herein we present a series of 31 patients with hypothyroidism of different aetiologies treated with the novel liquid LT4 formulation in standard clinical care in light of the latest scientific publications on liquid LT4 formula. We observed normalization of thyroid function tests shortly after introduction of liquid LT4, irrespective of concurrent diseases or concomitant medications that could diminish LT4 absorption. In more detail, the treatment with liquid LT4 managed to normalize thyroid-stimulating hormone (TSH) concentrations in patients without any known causes of LT4 absorption disturbances, as well as in those with malabsorption: with gastric bypass, partial small and large intestine resection, scleroderma, gluten intolerance, celiac disease, atrophic gastritis, and polytherapy. In conclusion, considering many factors disturbing LT4 absorption, hypothyroidism therapy with liquid LT4 seems to be a particularly effective option.