Levothyroxine sodium oral solution to control thyroid function in a patient with hypothyroidism and celiac disease

Liquid Thyroxine Improves Outcomes in Hypothyroid Patients With Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome

OBJECTIVE

Malabsorption of levothyroxine (LT4) is often seen in patients with hypothyroidism and gastrointestinal (GI) conditions. Our study was designed to establish the prevalence of small intestinal bacterial overgrowth (SIBO) in patients with hypothyroidism and irritable bowel syndrome (IBS), and to demonstrate that liquid LT4 is more consistently absorbed vs tablet, leading to improvement in thyroid and GI symptoms.

METHODS

This was a single-center, open label, prospective cohort study of liquid LT4 in 75 adult patients with hypothyroidism and IBS. Patients were transitioned from LT4 tablets to solution at equivalent dosing. Patients returned at 6 and 12 weeks for repeat thyroid levels and completion of validated questionnaires. A standard 2-hour SIBO breath test was administered at Week 6. Patients recorded daily stool appearance and frequency.

RESULTS

Prevalence of SIBO was 65.3%. Liquid LT4 normalized thyroid stimulating hormone (TSH) in a higher percentage of patients vs tablet (77.55% vs 57.14%); significantly decreased TSH in subjects with SIBO; improved hypothyroid symptoms, IBS symptoms, stool appearance in all groups, and significantly altered bowel frequency among those with SIBO.

CONCLUSION

Small intestinal bacterial overgrowth (SIBO) is common in patients with hypothyroidism and IBS. Among SIBO patients, LT4 tablets were inefficiently absorbed, leading to suboptimal thyroid control; however, transitioning from LT4 tablets to solution normalized TSH and improved hypothyroid symptoms. Liquid LT4 also significantly improved GI symptoms in all patients with hypothyroidism and IBS, regardless of SIBO status. Additionally, 1 in 5 patients had complete resolution of IBS symptoms after switching from LT4 tablets to solution, independent of changes in TSH.

Switching from Natural Desiccated Thyroid to a Liquid Formulation of Levothyroxine for Hypothyroidism

Natural desiccated thyroid (NDT) is a treatment option for many patients with hypothyroidism, but some still exhibit symptoms despite achievement of normal levels of thyroid stimulating hormone (TSH). In this retrospective case series, 13 patients with hypothyroid symptoms were switched from NDT to a liquid formulation of levothyroxine (LT4; Tirosint®-SOL). Laboratory values ≥4 weeks following the switch showed a decrease in TSH levels, maintenance of free triiodothyronine (fT3) levels, and significant increases in free thyroxine (fT4) levels. Patients reported good tolerability, and case summaries are presented for four patients. In summary, this small retrospective case series showed that patients who still had hypothyroid symptoms despite use of NDT can respond well to oral LT4 liquid formulation, including patients who are intolerant of gluten and/or lactose or on hormone replacement therapy or iron supplementation.

Levothyroxine: Conventional and novel drug delivery formulations

Despite the fact that levothyroxine is one of the most prescribed medications in the world, its bioavailability has been reported to be impaired by many factors, including interfering drugs or foods and concomitant diseases, and persistent hypothyroidism with a high dose of levothyroxine is thus elicited. Persistent hypothyroidism can also be induced by noninterchangeability between formulations and poor compliance. To address these issues, some strategies have been developed. Novel formulations (liquid solutions and soft-gel capsules) have been designed to eliminate malabsorption. Some other delivery routes (injections, suppositories, sprays, and sublingual and transdermal administrations) are aimed at circumventing different difficulties in dosing, such as thyroid emergencies and dysphagia. Moreover, nanomaterials have been used to develop delivery systems for the sustained release of levothyroxine to improve patient compliance and reduce costs. Some delivery systems encapsulating nanoparticles show promising release profiles. In this review, we first summarize the medical conditions that interfere with the bioavailability of oral levothyroxine and discuss the underlying mechanisms and treatments. The efficacy of liquid solutions and soft-gel capsules are systematically evaluated. We further summarize the novel delivery routes for levothyroxine and their possible applications. Nanomaterials in the levothyroxine field are then discussed and compared based on their load and release profile. We hope the article provides novel insights into the drug delivery of levothyroxine.

New Approach to Addison Disease: Oral Manifestations Due to Endocrine Dysfunction and Comorbidity Burden

This review highlights oral anomalies with major clinical impact in Addison disease (AD), including dental health and dermatologic features, through a dual perspective: pigmentation issues and AD comorbidities with oral manifestations. Affecting 92% of AD patients, cutaneomucosal hyperpigmentation is synchronous with or precedes general manifestations by up to a decade, underlying melanocytic infiltration of the basal epidermal layer; melanophages in the superficial dermis; and, rarely, acanthosis, perivascular lymphocytic infiltrate, and hyperkeratosis. Intraoral pigmentation might be the only sign of AD; thus, early recognition is mandatory, and biopsy is helpful in selected cases. The buccal area is the most affected location; other sites are palatine arches, lips, gums, and tongue. Pigmented oral lesions are patchy or diffuse; mostly asymptomatic; and occasionally accompanied by pain, itchiness, and burn-like lesions. Pigmented lingual patches are isolated or multiple, located on dorsal and lateral areas; fungiform pigmented papillae are also reported in AD individuals. Dermoscopy examination is particularly indicated for fungal etiology; yet, it is not routinely performed. AD’s comorbidity burden includes the cluster of autoimmune polyglandular syndrome (APS) type 1 underlying AIRE gene malfunction. Chronic cutaneomucosal candidiasis (CMC), including oral CMC, represents the first sign of APS1 in 70–80% of cases, displaying autoantibodies against interleukin (IL)-17A, IL-17F ± IL-22, and probably a high mucosal concentration of interferon (IFN)-γ. CMC is prone to systemic candidiasis, representing a procarcinogenic status due to Th17 cell anomalies. In APS1, the first cause of mortality is infections (24%), followed by oral and esophageal cancers (15%). Autoimmune hypoparathyroidism (HyP) is the earliest endocrine element in APS1; a combination of CMC by the age of 5 years and dental enamel hypoplasia (the most frequent dental complication of pediatric HyP) by the age of 15 is an indication for HyP assessment. Children with HyP might experience short dental roots, enamel opacities, hypodontia, and eruption dysfunctions. Copresence of APS-related type 1 diabetes mellitus (DM) enhances the risk of CMC, as well as periodontal disease (PD). Anemia-related mucosal pallor is related to DM, hypothyroidism, hypogonadism, corresponding gastroenterological diseases (Crohn’s disease also presents oral ulceration (OU), mucogingivitis, and a 2–3 times higher risk of PD; Biermer anemia might cause hyperpigmentation by itself), and rheumatologic diseases (lupus induces OU, honeycomb plaques, keratotic plaques, angular cheilitis, buccal petechial lesions, and PD). In more than half of the patients, associated vitiligo involves depigmentation of oral mucosa at different levels (palatal, gingival, alveolar, buccal mucosa, and lips). Celiac disease may manifest xerostomia, dry lips, OU, sialadenitis, recurrent aphthous stomatitis and dental enamel defects in children, a higher prevalence of caries and dentin sensitivity, and gingival bleeding. Oral pigmented lesions might provide a useful index of suspicion for AD in apparently healthy individuals, and thus an adrenocorticotropic hormone (ACTH) stimulation is useful. The spectrum of autoimmune AD comorbidities massively complicates the overall picture of oral manifestations.

What about TSH and Anti-Thyroid Antibodies in Patients with Autoimmune Thyroiditis and Celiac Disease Using a Gluten-Free Diet? A Systematic Review

The prevalence of celiac disease (CD) in patients with chronic autoimmune thyroiditis (CAIT) is estimated to be between 2 and 7.8%. A gluten-free diet (GFD) in patients with CD is suggested to have a beneficial effect on CAIT. Thus, the present systematic review was undertaken to achieve more robust evidence about the change in thyroid stimulating hormone (TSH) and thyroid-specific antibodies (T-Ab) levels obtained in CD patients following a GFD. A specific search strategy was planned. The last search was performed on March 2022. The following data were mainly searched for in order to be extracted: sample size, mean and/or median with standard deviation (SD), and error (SE), individually, of thyroid hormones and T-Ab at baseline and after GFD, and the duration of the study. The initial search retrieved 297 records and 6 articles met the inclusion criteria. In total, 50 patients with both CD and CAIT and 45 controls were reported. The effects of a GFD on the thyroid hormonal and immunological profile could be extracted only in a part of the studies. Two studies were case reports. A low risk of bias was observed. These findings advise further studies, ideally randomized, in order to better investigate the potential relationship between GFD and thyroid homeostasis. The level of evidence is not still sufficient to recommend GFD to patients with CAIT.