Levothyroxine 200microgram / Liothyronine 50microgram tablets

Abstract Disclosure: Y. Ayasa: None. A. Omarion: None. Z. Omarion: None. B. Jayouse: None. H. Ayesh: None. Background: Hypothyroidism, a common endocrine disorder, is predominantly treated with levothyroxine (LT4) monotherapy, which effectively normalizes thyroid-stimulating hormone (TSH) levels. However, many patients report persistent symptoms, including fatigue, cognitive difficulties, and diminished quality of life (QoL), despite achieving biochemical euthyroidism. This unmet need has driven interest in combination therapy with LT4 and liothyronine (LT3). While some studies suggest potential benefits of LT4+LT3 therapy in alleviating symptoms and improving QoL, the evidence remains inconsistent. This meta-analysis aims to provide a systematic evaluation of LT4 monotherapy and LT4+LT3 combination therapy in managing persistent hypothyroid symptoms.Methods:A systematic literature search of PubMed, Cochrane Library, and Scopus identified 25 studies, of which 8 met the inclusion criteria. The primary outcome was QoL improvement, assessed using validated tools such as SF-36 and ThyPRO. Secondary outcomes included symptom score changes and adverse events. Random-effects models were used for data synthesis, and heterogeneity was quantified using the I² statistic.Results:Five studies comparing LT4 and LT4+LT3 combination therapy reported QoL outcomes. The standardized mean difference (SMD) for QoL improvement with LT4+LT3 versus LT4 was 0.1185 (95% confidence interval [CI]: -0.0971 to 0.3342, p = 0.2813), indicating no significant difference. Analysis of symptom scale improvement from five studies demonstrated a small but statistically significant benefit for LT4+LT3 therapy (SMD: -0.3552, 95% CI: -0.5869 to -0.1236, p = 0.0026). Heterogeneity was moderate for symptom outcomes (I² = 30.5%) but high for QoL outcomes (I² = 70.1%).Conclusion:While LT4+LT3 combination therapy offers a modest improvement in symptom scores, it does not significantly enhance QoL compared to LT4 monotherapy. These findings suggest that combination therapy may benefit a subset of hypothyroid patients with persistent symptoms. Further large-scale, high-quality randomized controlled trials are needed to clarify its role in clinical practice. Presentation: Monday, July 14, 2025

Abstract licence: CC BY-NC-ND 4.0

Levothyroxine (LT4) is the standard treatment for hypothyroidism and the most widely prescribed medication worldwide. Although generally safe, regulatory reports list potential cardiac, neuropsychiatric and musculoskeletal adverse events (AEs). Clarifying their clinical relevance is essential. We systematically searched MEDLINE, Embase, CENTRAL and Google Scholar for randomized controlled trials (RCTs) and observational studies reporting predefined AEs. Eligible comparators included placebo, no treatment, liothyronine (LT3), usual-dose LT4 or LT4 monotherapy when LT4/T3 combination therapy was studied. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated. TSH values at baseline and post-treatment were recorded to contextualize AEs by thyroid status (euthyroid, suppressed or hypothyroid). Twelve studies (n = 1817) were included: seven RCTs, two crossover trials, two case-control studies and one quasi-experimental study. Cardiac AEs (tachycardia, palpitations, angina, atrial fibrillation), neuropsychiatric AEs (headache, tremor, insomnia, anxiety, depression) and musculoskeletal AEs (myalgia) were reported; however, most comparisons were statistically nonsignificant and clinically not meaningful, indicating that LT4 at replacement doses is generally safe. AEs primarily occurred when TSH was suppressed, whereas in euthyroid patients, blinded placebo-controlled trials showed no significant differences, confirming a very low risk of LT4-related side effects. Some subjective symptoms may reflect placebo or nocebo effects rather than true drug toxicity. LT4 at replacement doses is safe, and AEs are predominantly associated with suppressed TSH or subjective effects. Interpretation of AEs should always consider thyroid status, highlighting the importance of maintaining euthyroidism.

Abstract licence: CC BY-NC

Background/Objectives: Thyroid hormones, considered safe in therapeutic doses, are used to treat hypothyroidism, a common condition. Due to a combination of factors, including their mechanism of action, availability, and low price, these drugs are used illegally, mainly to improve performance, to assist in weight loss, or for attempting suicide. Their overuse can lead to serious health consequences, including death. Although thyroid hormones are abused, there are no studies assessing the scale, characteristics, and consequences of their illegal use. The aim of this study was to evaluate case reports of thyroid hormone poisoning from the last 30 years, assessing their dynamics and characteristics. Methods: Full-text clinical case studies were obtained by searching PubMed, Google Scholar, MEDLINE, Embase, Web of Science, and Scopus for the following terms: "thyroid hormones", "thyroxine", "levothyroxine", "triiodothyronine", and "liothyronine", as well as "intoxication", "overdose", and "poisoning". This study adhered to Preferred Reporting for Systematic Reviews and Meta-analyses (PRISMA) guidelines for systematic reviews. Results: Thyroid hormones are abused particularly by athletes, persons trying to lose weight, or those attempting suicide. There has been an upward trend in thyroid hormone poisoning over the past 30 years, particularly since 2015. The same trend has been observed in cases of thyroid hormone use for doping, among other performance-enhancing drugs. Thyroid hormone use for doping was the most common cause of poisoning with these drugs, with other clinical manifestations from poisonings due to other causes. No upward trend has been observed in the use of thyroid hormones in suicide attempts since 2017, as this number remains stable. Conclusions: Although exploratory in nature, our work indicates that thyroid hormone poisoning, associated mostly with the illegal use of anabolic-androgenic steroids, exhibits an increasing tendency. Moreover, thyroid hormone abuse is an important issue in suicidology.

Abstract licence: CC BY

BackgroundWhile levothyroxine (L-T4) therapy is standard for hypothyroidism, its direct effects on specific echocardiographic parameters of cardiac function remain underexplored in comprehensive meta-analyses.MethodsWe systematically searched multiple databases up to June 2025 for randomized controlled trials and prospective cohort studies assessing L-T4 therapy on echocardiographic parameters in hypothyroid adults. Data on cardiac indices, intervention details, follow-up, and disease types were extracted. Risk of bias was assessed using standard tools. A random-effects model calculated mean differences (MDs) and assessed heterogeneity. Subgroup analyses evaluated treatment type, follow-up duration, and underlying disease.ResultsSix studies (2 RCTs and 4 cohort studies) were included. Overall, L-T4 intervention did not significantly alter the LV Tei Index (MD = 0.0214, 95% CI: -0.0294 to 0.0722, p=0.4083) or LVEF (MD = -0.2258, 95% CI: -0.8990 to 0.4475, p=0.5110). However, a statistically significant increase in Mitral E velocity (MD = -0.0646, 95% CI: -0.1138 to -0.0154, p=0.0100) and Mitral A velocity (MD = -0.0646, 95% CI: -0.1138 to -0.0154, p=0.0100) was observed. Subgroup analyses for LV Tei Index showed a statistically significant improvement in the 12-month follow-up subgroup (MD = 0.0672, 95% CI: 0.0161 to 0.1183) and in congenital hypothyroidism (MD = 0.0300, 95% CI: 0.0044 to 0.0556). For LVEF, a statistically significant increase was found in the 12-week follow-up subgroup (MD = -7.9300, 95% CI: -14.4844 to -1.3756) and the overt hypothyroidism subgroup (MD = -7.9300, 95% CI: -14.4844 to -1.3756). The effect of L-T4 on Mitral E and Mitral A velocities varied significantly across disease types (p=0.0304 for both), with a significant increase noted in the congenital hypothyroidism subgroup for both. No significant change was observed in the E/A ratio (MD = -0.0058, 95% CI: -0.0360 to 0.0244, p=0.7058), with no significant subgroup differences.ConclusionL-T4 exerts differential effects on echocardiographic measures of cardiac function, with specific improvements influenced by follow-up duration and underlying etiology.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/view/, CRD420251274519.

Abstract licence: CC BY