Search

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.

Hypothyroidism is a common endocrine disorder affecting 3-15% of the adult population in subclinical form and 0.3-0.8% as overt disease. The mainstay of treatment is replacement monotherapy with levothyroxine (LT4). Currently several oral LT4 formulations including tablets, softgel capsules, and liquid formulations are available. Liquid LT4 is manufactured as LT4 solution in 85% glycerol and 96% ethanol and as LT4 solution in purified water and glycerol. The latest formulation, Tirosint SOL, gained FDA approval in 2017. To evaluate the clinical utility of liquid LT4 we reviewed the literature using three databases: PubMed/MEDLINE, Scopus, and Embase and found 405 articles among which 23 prospective and two retrospective studies were further evaluated. Finally, several case reports on rare clinical conditions were discussed. Our review demonstrated that liquid LT4 was more effective than tablet formulation in patients with malabsorption caused by interfering diseases, drugs, and bariatric surgery. The better pharmacokinetics of liquid LT4 was also confirmed in subjects without malabsorption: patients on replacement or suppressive therapy, who switched from tablet to liquid formulation in equivalent dose, gained better hormonal control, and required less frequent TSH measurements. The drug also appeared effective and easy to handle in patients fed by enteric tube. Liquid LT4 appeared equally effective whenever taken before or during breakfast. The analysis of the drug utility in particular populations including newborns, pregnant women, and the elderly confirmed the high value and safety of liquid LT4. However, in neonates the higher incidence of TSH suppression on liquid in comparison to tablet LT4 therapy was noted, and particular attention to avoid over-treatment must be paid. Concluding: the literature review revealed that liquid LT4 is especially advantageous in patients with malabsorption and the critically ill, but it seems also very promising in common therapy. The lack of alcohol content in the new formulation makes Tirosint SOL especially attractive.

Introduction: Foetal hypothyroidism negatively impacts somatic and neurological child development and can be the cause of serious obstetric and perinatal complications. We present a rare case of a large foetal dyshormonogenetic goitre, causing foetal neck hyperexten-sion, oesophageal compression, and cardiac high-output failure., Material and Methods: A foetal goitre complicated by cardiomegaly and polyhydramnios was diagnosed at 23 weeks of gestation (WG) on a routine ultrasonographic (US) assessment in a healthy nullipara. Foetal blood sampling was performed and a severe foetal hypothyroid-ism was diagnosed. Treatment was undertaken with an intra-amniotic followed by combined intra-amniotic and intravenous injections of L-thyroxine (L-T4). A total of 11 doses of L-T4 were administered between 24-37 WG to the foetus., Results: A complete regression of foetal goitre, cardiomegaly, and polyhydramnios was observed. At 38 WG the patient delivered vagi-nally a male infant with mild hypothyroidism and no signs of goitre or cardiomegaly on postnatal US. Neurological development of the one year old baby is normal., Conclusions: The effective diminishing of serum TSH concentration and goitre size was reached after combined intra-amniotic and in-travenous L-T4 injections were given. L-T4 requirement in the foetus is equal to or above 15 μg/kg daily and should be given in weekly intervals due to its rapid metabolism by the foetus and by placental type 3 deiodinase. Intra-amniotic L-T4 administration may be inef-fective when a large goitre indisposes amniotic fluid swallowing by the foetus, so then the combined L-T4 injections into the umbilical vein and intra-amniotically in experienced hands seems to be a reasonable and effective option.

Total thyroidectomy followed by 131I ablation and thyroxine suppressive therapy is recommended for the treatment of differentiated thyroid carcinomas. Thyroxine should be given at a dose sufficient to suppress TSH to low or undetectable levels. These patients are categorized as subclinical hyperthyroidism subjects. Some cardiovascular effects of subclinical hyperthyroidism, such as an increase in left ventricular mass and accelerated bone loss, should be taken into consideration. Estrogens reduce the loss of bone mass in thyrotoxic postmenopausal patients and have cardioprotective effects. The relatively high incidence of thyroid carcinoma in women suggests that estrogen and/or progesterone may be important for the development of these neoplasms. Immunohistochemical study has established that steroid receptors are present in thyroid tissue. Many authors suggest that estrogens by itself do not appear to affect the natural history of thyroid cancer. Besides the thyroid, active iodide transports catalysed by the sodium/iodide symporter occurs in the lactating mammary gland. An increased risk of breast carcinoma in women with thyroid carcinoma due to carcinogenicity of radioiodine has been reported by some but not all investigators. Hormone replacement therapy in the thyroxine treated postmenopausal women consists in conventional oral or transdermal estrogen combined with progesterone. In some cases the daily dose of thyroxine should be increased to achieve TSH suppression.

Unlabelled: The aim of the study was to estimate the dose of thyroxine required by pregnant women who had undergone total thyreoidectomy and radioiodine treatment for thyroid cancer. Material consisted of 4 pregnant women, aged mean 30.8 years. One of patients was studied during 2 consecutive pregnancies. The daily mean dose of thyroxine was 175 micrograms. The control group consisted of 7 women with primary hypothyroidism aged mean 33.5 years, who were treated with replacement doses of thyroxine. One of them was pregnant twice. The mean daily dose of thyroxine was 106.3 micrograms. The estimation of TSH, fT4 were repeated every 4 weeks., Results: In all cases natural deliveries took place. All infants were alive and had no congenital malformations and no clinical or biochemical thyroid dysfunction was found. Pregnant women treated for thyroid cancer needed to have optimized their suppressive therapy by increasing the dose of thyroxine by 26% at the first trimester, 27% at the second and 38% at the last one. Statistically significant increase was found at the 1st trimester of pregnancy and it remained at the same level till the delivery. Pregnant hypothyroid women needed to have optimized their replacement thyroxine therapy by increasing of the dose by 53% at the first trimester, by 49% at the second and by 53% at the last one. Similarly to the 1st group of patients, we noticed statistically significant increase at the 1st trimester of pregnancy., Conclusion: In pregnant women who have been previously treated for thyroid cancer the suppressive dose of thyroxine needs to be increased by 26-38% which is slightly less than the increase of the replacement dose in hypothyroid pregnant women.