Difficulties in achieving euthyroid status in a patient with differentiated thyroid cancer after sleeve gastrectomy

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Liquid levothyroxine in the treatment of myxoedema coma

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

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.

Liquid levothyroxine formulations in patients taking drugs interfering with L-T4 absorption

PURPOSE

To describe the current knowledge on thyroid hormonal profile in patients on liquid L-T4 therapy and drugs known to interfere with L-T4 absorption.

METHODS

A PubMed/MEDLINE, Web of Science, and Scopus research was performed. Case reports, case series, original studies and reviews written in English and published online up to 31 August 2022 were selected and reviewed. The final reference list was defined based on the relevance of each paper to the scope of this review.

RESULTS

The available data showed that novel levothyroxine formulations circumvent gastric pH impairment due to multiple interfering drugs such as proton pump inhibitors, calcium or iron supplements, sevelamer, aluminum/magnesium hydroxide and sodium alginate.

CONCLUSION

New formulations can be taken simultaneously with drugs interfering with L-T4 absorption, in particular liquid formulations. Softgel capsules need more studies to support these data.

Improvements in Quality of Life and Thyroid Parameters in Hypothyroid Patients on Ethanol-Free Formula of Liquid Levothyroxine Therapy in Comparison to Tablet LT4 Form: An Observational Study

Levothyroxine (LT4) is a standard therapy in hypothyroidism; however, its bioavailability and therapeutic effects might be affected by many factors. Data shows that therapy with liquid LT4 characterized by quicker pharmacokinetics provides better thyroid hormones control than tablet LT4. We addressed the quality of life (QoL) and efficacy of the new ethanol-free formula of liquid LT4 (Tirosint^®SOL) treatment in 76 euthyroid patients with primary (PH, n = 46) and central hypothyroidism (CH, n = 30), and compared the results to retrospective data on equivalent doses of tablet L-T4 therapy. After 8 weeks of liquid LT4 therapy, we found a significant improvement in QoL in both PH and CH patients. TSH levels were unaltered in PH patients. Free hormone levels (fT4 and fT3) increased in all the patients, with the exception of fT3 in the CH group. SHBG and low-density lipoprotein (LDL) also improved. Liquid LT4 therapy provided a better thyroid hormone profile and improvement in patients' QoL than the tablet form, which was possibly due to the more favorable pharmacokinetics profile resulting in better absorption, as suggested by the increased free thyroid hormone levels. In summary, this is the first study addressing the QoL in hypothyroid patients, including primary and central hypothyroidism, treated with liquid LT4 formula in everyday practice.

Increased efficacy of hypothyroidism control with liquid levothyroxine [Większa skuteczność lewotyroksyny w postaci płynnej w wyrównywaniu niedoczynności tarczycy]

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Expert opinion on liquid L-thyroxine usage in hypothyroid patients and new liquid thyroxine formulation - Tirosint SOL [Opinia ekspertów dotycząca stosowania płynnej postaci lewotyroksyny oraz nowego preparatu Tirosint SOL u chorych na niedoczynność tarczycy]

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.

Levothyroxine Therapy in Gastric Malabsorptive Disorders

Oral levothyroxine sodium is absorbed in the small intestine, mainly in the jejunum and the ileum being lower the absorption rate at duodenal level. The time interval between the ingestion of oral thyroxine and its appearance in the plasma renders unlike a gastric absorption of the hormone. However, several evidence confirm the key role of the stomach as a prerequisite for an efficient absorption of oral levothyroxine. In the stomach, in fact, occur key steps leading to the dissolution of thyroxine from the solid form, the process bringing the active ingredient from the pharmaceutical preparation to the aqueous solution. In particular, gastric juice pH, volume, viscosity, as well as gastric emptying time seem to be the most important limiting factors. These hypotheses are confirmed by the detection of an increased need for levothyroxine in patients with Helicobacter pylori infection, chronic atrophic gastritis, gastroparesis, or in simultaneous treatment with drugs interfering with gastric acidic output. The aim of the present article is to focus on the knowledge of pathophysiologic events that determine the absorptive fate of traditional (tablet) and alternative thyroxine preparations (softgel capsule and liquid solution) in patients bearing gastric disorders.

Levothyroxine Therapy in Thyrodectomized Patients

Administration of the optimal dose of levothyroxine (LT4) is crucial to restore euthyroidism after total thyroidectomy. An insufficient or excessive dosage may result in hypothyroidism or thyrotoxicosis, either one associated with a number of symptoms/complications. Most literature regarding the LT4 dosage deals with the treatment of primary hypothyroidism, whereas a limited number of studies handle the issue of thyroxin replacement after total thyroidectomy. A literature review was performed focusing on all papers dealing with this topic within the last 15 years. Papers that reported a scheme to calculate the proper LT4 dose were collected and compared to set up a review exploring limits and drawbacks of LT4 replacement therapy in the wide population of patients who had undergone thyroidectomy. Most of the methods for monitoring and adjusting thyroid hormone replacement after thyroidectomy for benign disease use LT4 at an empirical dose of approximately 1.6 μg/kg, with subsequent changes according to thyroid function test results and assessments of the patient's symptoms. Approximately 75% of patients require a dose adjustment, suggesting that factors other than body weight play a role in the determination of the proper LT4 dose. Hence, several schemes are reported in the literature for the proper initial dose of LT4. An inadequate level of thyroid hormone levels in these patients can be due to several factors. The most common ones that lead to the necessity of LT4 dose adjustments include lack of compliance, changes in LT4 formulation, dosage errors, increased serum levels of T4-binding globulin, body mass changes, and dietary habits. Moreover, concomitant ingestion of calcium supplements, ferrous sulfate, proton-pump inhibitors, bile acid sequestrants, and sucralfate might influence LT4 absorption and/or metabolism. Furthermore, some gastrointestinal conditions and their treatments can contribute to suboptimal LT4 performance by altering gastric acidity and thereby reducing its bioavailability, particularly in the solid form. Beyond the classic tablet form, new formulations of LT4, such as a soft gel capsule and an oral solution, recently became available. The liquid formulation is supposed to overcome the food and beverages interference with absorption of LT4 tablets.

Increased Requirement of Replacement Doses of Levothyroxine Caused by Liver Cirrhosis

BACKGROUND

Since hypothyroidism is a fairly common dysfunction, levothyroxine (L-T4) is one of the most prescribed medications. Approximately 70% of the administered L-T4 dose is absorbed. The absorption process takes place in the small intestine. Some disorders of the digestive system and some medicines, supplements, and drinks cause L-T4 malabsorption, resulting in failure of serum TSH to be normal. Only rarely liver cirrhosis is mentioned as causing L-T4 malabsorption.

CASE REPORT

In this study, we report increased requirement of daily doses of l-thyroxine in two patients with the atrophic variant of Hashimoto's thyroiditis and liver cirrhosis. In one patient, this increased requirement could have been contributed by the increased serum levels of the estrogen-dependent thyroxine-binding globulin (TBG), which is the major plasma carrier of thyroid hormones. In the other patient, we switched from tablet L-T4 to liquid L-T4 at the same daily dose. Normalization of TSH levels was achieved, but TSH increased again when she returned to tablet L-T4.

CONCLUSION

Liver cirrhosis can cause increased L-T4 requirements. In addition to impaired bile secretion, the mechanism could be increased serum TBG. A similar increased requirement of L-T4 is observed in other situations characterized by elevation of serum TBG. Because of better intestinal absorption, L-T4 oral liquid formulation is able to circumvent the increased need of L-T4 in these patients.

Adherence to Levothyroxine Treatment Among Patients With Hypothyroidism: A Northeastern Italian Survey

Background: A significant number of patients show sub-optimal adherence to levothyroxine (LT4) therapy, mainly because they have to postpone their breakfast by at least 30 min. The aim of this observational cross-sectional study was to assess the therapeutic compliance of patients on LT4 treatment and to verify the preference of a lifetime treatment in tablet or liquid form. Patients and Methods: Ambulatory care patients aged 18 years or older, affected by hypothyroidism and on LT4 treatment (in tablet or liquid form) were administered the eight-item Morisky Medication Adherence Scale (MMAS-8). The MMAS-8 questionnaire was supplemented with 3 further items to specifically evaluate preference between tablet and liquid forms of LT4 for lifetime treatment. Results: A total of 320 patients (272 female), median age 47.9 ± 15.6 years (range, 20-78 years), completed the MMAS-8 questionnaire. Eighty-seven percent of the participants were adhering to their treatment for both tablet and liquid LT4 formulations, although significant differences emerged. Patients on LT4 tablets forgot to take their medication more frequently (p < 0.001), felt hassled about sticking to their treatment plan (p < 0.001), and had difficulty remembering to take all their medication(s) (p < 0.001) than those on liquid LT4 treatment. Conclusions: Adherence to LT4 treatment was high for both tablet and liquid formulations. Taking LT4 at breakfast was the most convenient option for most patients.