Levothyroxine Sodium

About: Levothyroxine Sodium is a research topic. Over the lifetime, 235 publications have been published within this topic receiving 4827 citations.

Rapid Cycling Bipolar Affective Disorder: II. Treatment of Refractory Rapid Cycling With High-Dose Levothyroxine: A Preliminary Study

Abstract: • Eleven patients with rapid cycling bipolar affective disorder whose symptoms were refractory to their current medication regimen were entered into an open trial of high-dose levothyroxine sodium added to a stable regimen of those medications. At baseline, all patients exhibited a rapid cycling pattern and were evaluated prospectively through at least one affective episode. Levothyroxine was added to the baseline medication regimen, and the dosage was increased until clinical response occurred or until side effects precluded further increase. While patients were taking levothyroxine, scores on both depressive and manic symptom rating scales decreased significantly compared with baseline. This improvement was due to the clear-cut response of depressive symptoms in 10 of 11 patients, with manic symptoms responding in five of the seven patients who exhibited them during baseline evaluation. Four patients then underwent singleor double-blind placebo substitution; three patients relapsed into either depression or cycling. Treatment response did not depend on previous thyroid status. In 9 of 10 responsive patients, supranormal circulating levels of free thyroxine were necessary to induce clinical response. Side effects were minimal, and there were no signs or symptoms of levothyroxine-induced hypermetabolism.

Levothyroxine treatment of subclinical hypothyroidism, fatal and nonfatal cardiovascular events, and mortality

Abstract: Background Subclinical hypothyroidism (SCH) has been associated with ischemic heart disease (IHD); however, it is unknown whether treatment of SCH with levothyroxine sodium will reduce the risk of IHD. The aim of this study was to investigate the association between levothyroxine treatment of SCH with IHD morbidity and mortality. Methods We used the United Kingdom General Practitioner Research Database to identify individuals with new SCH (serum thyrotropin levels of 5.01-10.0 mIU/L and normal free thyroxine levels) recorded during 2001 with outcomes analyzed until March 2009. All analyses were performed separately for younger (40-70 years) and older (>70 years) individuals. Hazard ratios (HRs) for IHD events (fatal and nonfatal) were calculated after adjustment for conventional IHD risk factors, baseline serum thyrotropin levels, and initiation of levothyroxine treatment as a time-dependent covariate. Results Subclinical hypothyroidism was identified in 3093 younger and 1642 older individuals. For a median follow-up period of 7.6 years, 52.8% and 49.9% of younger and older patients with SCH were treated with levothyroxine, respectively. There were 68 incident IHD events in 1634 younger patients treated with levothyroxine (4.2%) vs 97 IHD events in 1459 untreated individuals (6.6%) (multivariate-adjusted HR, 0.61; 95% CI, 0.39-0.95). In contrast, in the older group there were 104 events in 819 treated patients (12.7%) vs 88 events in 823 untreated individuals (10.7%) (HR, 0.99; 95% CI, 0.59-1.33). Conclusions Treatment of SCH with levothyroxine was associated with fewer IHD events in younger individuals, but this was not evident in older people. An appropriately powered randomized controlled trial of levothyroxine in SCH examining vascular outcomes is now warranted.

Bioequivalence of Generic and Brand-name Levothyroxine Products in the Treatment of Hypothyroidism

Abstract: Objective. —To compare relative bioavailability of Synthroid, Levoxine (Levoxine has been renamed Levoxyl), and 2 generic levothyroxine sodium preparations. Design. —Single-blind (primary investigators blinded), randomized, 4-way crossover trial. Setting. —Ambulatory care. Patients. —Twenty-Two women with hypothyroidism who were clinically and chemically euthyroid and were receiving levothyroxine sodium, 0.1 or 0.15 mg. Interventions. —All patients received each of the 4 levothyroxine products for 6-week periods in the same dosage as their prestudy regimen with no washout period. The order of the drug sequences was randomly determined before study initiation. Main Outcome Measures. —Area under the curve, time to peak serum concentrations, and peak serum concentrations of thyroxine, triiodothyronine, and free thyroxine index for all 4 products. Results. —All data analyses were completed prior to unblinding of the product codes. No significant differences between the 4 products were found in area under the curve or peak serum concentrations of total thyroxine, total triiodothyronine, or free thyroxine index. Although Synthroid produced a more rapid rise in total serum triiodothyronine concentration and a higher total peak serum triiodothyronine concentration than the other products, these differences were not statistically significant ( P =.08). The Food and Drug Administration criterion for relative bioequivalence within 90% confidence intervals (0.8-1.25) was demonstrated ( P Conclusions. —The 4 generic and brand-name levothyroxine preparations studied are different but are bioequivalent by current Food and Drug Administration criteria and are interchangeable in the majority of patients receiving thyroxine replacement therapy. Further investigation is required to determine whether our results are equally applicable to all existing levothyroxine preparations.

Combined levothyroxine plus liothyronine compared with levothyroxine alone in primary hypothyroidism: a randomized controlled trial.

Abstract: ContextStandard therapy for patients with primary hypothyroidism is replacement with synthetic thyroxine, which undergoes peripheral conversion to triiodothyronine, the active form of thyroid hormone. Within the lay population and in some medical communities, there is a perception that adding synthetic triiodothyronine, or liothyronine, to levothyroxine improves the symptoms of hypothyroidism despite insufficient evidence to support this practice.ObjectiveTo evaluate the benefits of treating primary hypothyroidism with levothyroxine plus liothyronine combination therapy vs levothyroxine monotherapy.Design, Setting, and PatientsRandomized, double-blind, placebo-controlled trial conducted from May 2000 to February 2002 at a military treatment facility that serves active duty and retired military personnel and their family members. The trial included a total of 46 patients aged 24 to 65 years with at least a 6-month history of treatment with levothyroxine for primary hypothyroidism.InterventionPatients received either their usual dose of levothyroxine (n = 23) or combination therapy (n = 23), in which their usual levothyroxine dose was reduced by 50 µg/d and substituted with liothyronine, 7.5 µg, taken twice daily for 4 months.Main Outcome MeasuresScores on a hypothyroid-specific health-related quality-of-life (HRQL) questionnaire, body weight, serum lipid levels, and 13 neuropsychological tests measured before and after treatment.ResultsSerum thyrotropin levels remained similar and within the normal range in both treatment groups from baseline to 4 months. Body weight and serum lipid levels did not change. The HRQL questionnaire scores improved significantly in both the control group (23%; P<.001) and the combination therapy group (12%; P = .02), but these changes were statistically similar (P = .54). In 12 of 13 neuropsychological tests, outcomes between groups were not significantly different; the 1 remaining test (Grooved Peg Board) showed better performance in the control group.ConclusionCompared with levothyroxine alone, treatment of primary hypothyroidism with combination levothyroxine plus liothyronine demonstrated no beneficial changes in body weight, serum lipid levels, hypothyroid symptoms as measured by a HRQL questionnaire, and standard measures of cognitive performance.