Comparison of single daily dose of methimazole and propylthiouracil in the treatment of Graves' hyperthyroidism

Methimazole-induced urticaria in hyperthyroid patients: A safe re-administration protocol

PURPOSE

The safety profile of methimazole (MMI) seems to be better than propylthiouracil in the management of hyperthyroidism. It is therefore advisable to use IMM as the first choice in Graves' patients. It is important to keep this drug in patients regardless of minor side effects. We report a case series of MMI-induced urticaria and provide a stepwise protocol for the safe re-administration of MMI.

METHODS

It was a retrospective case series including all patients having manifested urticaria following MMI intake for hyperthyroidism; notified to the Pharmacovigilance Unit of the Clinical Pharmacology Department (March 2013-January 2022).

RESULTS

We have included 11 patients (SR: 0.22). The median time interval between the start of MMI and the onset of urticaria averaged 14.5 days. The median daily dose of MMI was 40mg. MMI was interrupted in all patients. Urticaria has progressively resolved after drug interruption and antihistamine intake. Reintroduction of MMI was performed in 10/11 patients as follows: one quarter of the daily dose on the first day, half of the daily dose on the 4th day, the three quarters of the daily dose on the 7th day, to reach the scheduled total dose on the 10th day. Cetirizine was added at the time of reintroduction and withdrawn 2 weeks later. All the patients were successfully controlled.

CONCLUSION

Given the importance of this drug in the management of hyperthyroidism, MMI should not be withdrawn in cases of urticaria. After the resolution of urticaria, a gradual reintroduction of MMI should be attempted with concomitant antihistamine therapy.

Prospective study to evaluate radioactive iodine of 20 mCi vs 10-15 mCi in Graves' disease

OBJECTIVES

To assess whether increasing radioactive iodine dose can increase treatment efficacy in Graves' disease.

METHODS

A prospective study was conducted, including 106 patients receiving 20 mCi (740 MBq) radioactive iodine (RAI), compared with a retrospective data, including 113 patients receiving 10-15 mCi (370-555 MBq) RAI. Remission and failure rates were evaluated at 6 months post-RAI. Statistical analysis was performed using logistic regression and Kaplan-Meier curves.

RESULTS

Patients receiving 20 mCi RAI demonstrated a significantly higher remission rate compared to the 10-15 mCi group (82.1% vs 66.4%, p = 0.009). Median time to remission was shorter in the 20 mCI group (3 vs 4 months, p = 0.002). Hypothyroidism at 6 months was more prevalent in the 20 mCi group (67% vs 53%, p = 0.03). Larger thyroid size (> 60 g) was associated with treatment failure (p = 0.02).

CONCLUSIONS

Higher dosage (20 mCi) RAI showed superior efficacy in achieving remission compared to lower dosages (10-15 mCi) in Graves' disease treatment.

Methimazole, an Effective Neutralizing Agent of the Sulfur Mustard Derivative 2-Chloroethyl Ethyl Sulfide

Sulfur mustard (SM), designated by the military as HD, is a highly toxic and dangerous vesicant that has been utilized as a chemical warfare agent since World War I. Despite SM's extensive history, an effective antidote does not exist. The effects of SM are predominantly based on its ability to alkylate important biomolecules. Also, with the potential for a fraction of SM to remain unreacted up to days after initial contact, a window of opportunity exists for direct neutralization of unreacted SM over the days following exposure. In this study, we evaluated the structure-activity relationship of multiple nucleophilic molecules to neutralize the toxic effects of 2-chloroethyl ethyl sulfide (CEES), a monofunctional analogue of SM, on human keratinocyte (HaCaT) cells. Cell viability, relative loss of extracellular matrix adhesions, and apoptosis caused by CEES were measured via MTT, cell-matrix adhesion (CMA), and apoptosis protein marker assays, respectively. A set of five two-carbon compounds with various functional groups served as a preliminary group of first-generation neutralizing agents to survey the correlation between mitigation of CEES's toxic effects and functional group nucleophilicity. Apart from thioacids, which produced additive toxicity, we generally observed the trend of increasing protection from cytotoxicity with increasing nucleophilicity. We extended this treatment strategy to second-generation agents which contained advantageous structural features identified from the first-generation molecules. Our results show that methimazole (MIZ), a currently FDA-approved drug used to treat hyperthyroidism, effectively reduced cytotoxicity, increased CMA, and decreased apoptosis resulting from CEES toxicity. MIZ selectively reacts with CEES to produce 2-(2-(ethylthio)ethylthio)-1-methyl-1H-imidazole (EEMI) in media and cell lysate treatments resulting in the reduction of toxicity. Based on these results, future development of MIZ as an SM therapeutic may provide a viable approach to reduce both the immediate and long-term toxicity of SM and may also help mitigate slower developing SM toxicity due to residual intact SM.

The management and metabolic characterization: hyperthyroidism and hypothyroidism

Hyperthyroidism and hypothyroidism are common diseases resulting from thyroid dysfunction, and are simple to diagnose and treat. The traditional treatment for hypothyroidism is thyroid hormone replacement therapy. The traditional treatments for hyperthyroidism include antithyroid drug, iodine radiotherapy, and surgery. Thyroid disease can be fatal in severe cases if untreated. Current statistical reference ranges used for diagnosis based on relevant biochemical parameters have been debated, and insufficient treatment can result in long-term thyroid hormone deficiency, which is associated with increased risk of cardiovascular disease and persistent symptoms. In contrast, overtreatment can result in heart disease and osteoporosis, particularly in older people and pregnant women. Therefore, under- or over-treatment should be avoided and treatment regimens should be monitored closely. A significant proportion of patients who achieve biochemical treatment goals still complain of significant symptoms. Systematic literature review was performed through the Embase (Elsevier), PubMed and Web of Science databases, and studies summarized evidence regarding treatment and management of hypothyroidism and hyperthyroidism, and reviewed clinical practice guidelines. We also reviewed the latest research on the metabolic mechanisms of hyperthyroidism and hypothyroidism, which contributed to understanding of thyroid diseases in the clinic. A reliable algorithm is needed to management, assessment, and treatment patients with hyperthyroidism and hypothyroidism, which can not only improve management efficiency, but also providing a broad application. In addition, the thyroid disorder showed a lipid metabolism tissue specificity in the Ventromedial Hypothalamus, and effect oxidative stress and energy metabolism of whole body. This review summarizes an algorithm for thyroid disease and the latest pathogenesis that would be useful to generalist and subspecialty physicians and others providing care for patients with this condition.

Efficacy and adverse events related to the initial dose of methimazole in children and adolescents with Graves' disease

PURPOSE

The first-line antithyroid drug for children and adolescents with Graves' disease (GD) is methimazole (MMI). This study evaluated the relationship between the initial MMI dose and the clinical course of GD after treatment.

METHODS

We studied the efficacy of the initial MMI dose and the relationship between the initial MMI dose and adverse events (AEs). We retrospectively enrolled 22 males and 77 females and divided those subjects into 3 groups according to the initial dose of MMI: <0.4 mg/kg/day (group A; n=32); 0.4-0.7 mg/kg/day (group B; n=39); and >0.7 mg/kg/day (group C; n=28).

RESULTS

The mean time to the normalization of free thyroxine (fT4) levels upon initial treatment was 5.64, 8.61, and 7.98 weeks in groups A, B, and C, respectively (P=0.116). The incidence of liver dysfunction, neutropenia, and skin rash was 12.5%, 20.5%, and 42.9% in groups A, B, and C, respectively (P=0.018). Neutropenia, as a severe AE, was absent in group A, but its prevalence was 7.7% in group B and 21.4% in group C (P=0.015). When comparing only groups B and C, the incidences of liver dysfunction and neutropenia were higher in group C (P=0.04 and P=0.021, respectively).

CONCLUSION

The mean time to the normalization of fT4 levels did not differ among the 3 groups, but the incidence of AEs was higher in the groups that received high MMI doses. High doses of MMI (>0.7 mg/kg/day) should be reconsidered as an initial treatment for children and adolescents with GD.

The efficiency and safety of methimazole and propylthiouracil in hyperthyroidism: A meta-analysis of randomized controlled trials

PURPOSE

The aim of this study was to evaluate the efficiency and safety of methimazole (MMI) and propylthiouracil (PTU) in the treatment of hyperthyroidism.

METHODS

Articles were searched through the PubMed, EMBASE, Cochrane Library, Web of Science, CNKI, Wanfang, and QVIP. The primary outcomes were clinical efficacy and thyroid hormone levels in MMI and PTU groups. The secondary outcomes were liver function indexes and adverse reactions in MMI and PTU groups. Results were expressed as weighted mean difference (WMD) or odds ratio (OR) with 95% confidence intervals (CIs). The Begg test was applied to assess the publication bias.

RESULTS

Totally, 16 randomized controlled trials were retained in this meta-analysis with 973 patients receiving MMI and 933 receiving PTU. The levels of triiodothyronine (T3) (WMD = -1.321, 95% CI: -2.271 to -0.372, P = .006), thyroxine (T4) (WMD = -37.311, 95% CI: -61.012 to -13.610, P = .002), Free T3 (FT3) (WMD = -1.388, 95% CI: -2.543 to -0.233, P = .019), Free T4 (FT4) (WMD = -3.613, 95% CI: -5.972 to -1.255, P = .003), and the risk of liver function damage (OR = 0.208, 95% CI: 0.146-0.296, P < .001) in the MMI group were lower than those in the PTU group. The thyroid-stimulating hormone level (WMD = 0.787, 95% CI: 0.380-1.194, P < .001) and the risk of hypothyroidism (OR = 2.738, 95% CI: 1.444-5.193, P = .002) were higher in the MMI group than those in the PTU group.

CONCLUSIONS

Although MMI might have higher risk of hypothyroidism than PTU, the efficacy of MMI may be better than PTU in patients with hyperthyroidism regarding reducing T3, T4, FT3, and FT4 levels, decreasing the risk of liver function damage and increasing the level of thyroid-stimulating hormone.

REGISTER NUMBER

osf.io/ds637 (https://osf.io/search/).

Variations in the Antithyroid Antibody Titre During Pregnancy and After Delivery

Background

Immunosuppression occurs during pregnancy, and the antithyroid antibody titre drops, rebounding after delivery. We aimed to determine variations in antithyroid antibody titres during pregnancy and after delivery.

Methods

This retrospective study was conducted in a single centre. Antibody titres of 142 patients were measured to assess variations in the levels of thyroid-stimulating hormone receptor antibodies (TRAbs), thyroid peroxidase antibodies (TPOAbs), and thyroid globulin antibodies (TgAbs). We compared the titres of each antibody between adjacent time periods (eg, first trimester (T1) vs second trimester (T2), T2 vs third trimester (T3), T3 vs the postpartum period (PP)) by paired t-test or the Wilcoxon test. Then, we analysed data from patients with complete laboratory examination results in all four periods with the Friedman test, performing comparisons among groups.

Results

In the TgAb group, significant differences existed between T1 and T2 and between T2 and T3 in the LT4 subgroup and between T1 and T2 in the no-medication subgroup. In the TRAb group, significant differences existed between T1 and T2 in the LT4 subgroup. In the TPOAb group, significant differences existed among each group in the LT4 subgroup, and there were significant differences between T1 and T2 and between T2 and T3 in the no-medication subgroup. The Friedman test showed that the P-values were 0.013 and 0.004 in the LT4 and no-medication subgroups of the TgAb group, respectively; 0.122 in the LT4 subgroup of the TRAb group; and <0.001 and 0.272 in the LT4 and no-medication subgroups of the TPOAb group, respectively. In the LT4 subgroup of the TgAb group, the P-values for comparisons of time periods were 0.602 between T1 and T2, 0.602 between T2 and T3, 0.006 between T1 and T3, and 0.602 between T3 and PP. In the no-medication subgroup of the TgAb group, the P-values were 0.078 between T1 and T2, 1.000 between T2 and T3, 0.011 between T1 and T3, and 0.078 between T3 and PP. In the LT4 subgroup of the TPOAb group, the P-values were 0.09 between T1 and T2, 0.014 between T2 and T3, <0.001 between T1 and T3, and 0.772 between T3 and PP.

Conclusion

We can conclude that the TgAb and TPOAb titres dropped during pregnancy.

Desensitization to Methimazole

OBJECTIVE

Thionamides (methimazole and propylthiouracil) have been associated with common side effects, such as rash and pruritus, and rare but serious adverse effects, such as agranulocytosis and hepatotoxicity. Methimazole is usually the preferred thionamide for the treatment of hyperthyroidism if the patient is not planning to conceive or not in the first trimester of pregnancy, given the less frequent dosing and lower risk of hepatotoxicity. In patients who experience rash or itching when treated with methimazole, switching them to propylthiouracil is one treatment option. Here we report our experience regarding desensitization to methimazole to allow continued treatment with methimazole as an alternative management option.

METHODS

We conducted a retrospective chart review of patients at a single institution who had side effects to methimazole and who were desensitized to methimazole under the supervision of an allergist. A total of 7 patients were included who experienced side effects to methimazole that did not include agranulocytosis or hepatotoxicity.

RESULTS

All 7 patients were able to take methimazole for treatment of their hyperthyroidism, either for continued medical therapy or as a bridge to definitive therapy, with either surgery or radioactive iodine treatment.

CONCLUSION

Under the supervision of an allergist, desensitization to methimazole is an option for treating patients who experience side effects to methimazole (excluding agranulocytosis and hepatotoxicity).

The Putative Role of Thyroid Hormones and Vitamin D on Severity and Quality of Life in Psoriasis

Introduction:

Psoriasis is a chronic immune-mediated inflammatory skin disease. The thyroid hormone receptors are expressed in human skin and the hormones exert their effects on epidermal proliferation and differentiation; they have been hypothesized to play a role in the pathogenesis of psoriasis. Vitamin D is involved in the maintenance of cutaneous barrier homeostasis. Several studies identified an association between polymorphisms of Vitamin D receptor and psoriasis susceptibility.

Subjects and Methods:

Thirty clinically diagnosed psoriasis patients in the age group between 20 and 50 years of both genders attending the outpatient department of dermatology were included as cases. Thirty healthy subjects attending routine health checkup were included as controls. Serum 25 hydroxycholecalciferol was estimated in Mini Vidas autoanalyzer by immunofluorescence technique and Thyroid stimulating hormone (TSH), free T3, and free T4 were estimated by chemiluminescence technology in Cobas e411. Dermatology quality of life index (DLQI) and psoriasis area severity index (PASI) questionnaire was used to assess the quality of life and severity of psoriasis respectively.

Results:

TSH level was significantly increased in psoriasis cases when compared to healthy controls but within reference range (P < 0.05). There is a significant negative correlation between PASI and 25-hydroxycholecalciferol and significant negative correlation between PASI and DLQI.

Conclusion:

Our study emphasizes the relationship between biochemical markers, severity of psoriasis, and quality of life. A multimodal holistic approach is needed for the treatment of psoriasis. Psychological support for stress management, drug therapy, and biochemical markers assessment for severity of psoriasis are the need of the hour.

A Population-Based Cohort Study on the Association of Hyperthyroidism With the Risk of Hyperlipidemia and the Effects of Anti-thyroid Drugs on Hepatic Gene Expression

There have been no reports on the association of hyperthyroidism with hyperlipidemia in patients undergoing treatment especially in Asia. To determine the association between hyperthyroidism and the risk of hyperlipidemia in patients, we conducted a retrospective cohort study using Longitudinal Health Insurance Database (LHID) from Taiwan, R.O.C. We also evaluate the influence of 6-n-propyl-2-thiouracil (PTU) and methimazole (MMI) on hepatic genes to explain changes in blood lipid levels in a hepatic cell line model. The cohort study involved 13,667 patients with hyperthyroidism, and the corresponding comparison cohort had four times as many patients. Using Kaplan-Meier analysis method, the results showed that, compared to patients without hyperthyroidism, the overall incidence of hyperlipidemia was significantly higher in the hyperthyroidism patients (18.7 vs. 11.8 cases/1,000 persons-years; adjusted HR 1.5; 95% CI, 1.41–1.59). With only PTU or MMI/carbimazole (CBM) treatment, patients with hyperthyroidism showed a 1.78-fold (95% CI, 1.50–2.11) and 1.43-fold (95% CI, 1.27–1.60) higher risk of hyperlipidemia than those without hyperthyroidism, respectively. Additionally, hyperthyroidism patients that received surgery only or surgery with I¹³¹ therapy tended to have a higher risk of hyperlipidemia. Although PTU and MMI treatment decreased the expression levels of genes responsible for circulating remnant lipoproteins, they increased the levels of lipogenic gene expression in hepatic cells. Thus, treatment of hyperthyroid patients with anti-thyroid drugs (ATDs), I¹³¹, or surgery is likely to induce hyperlipidemia. ATDs downregulate the expression of genes involved in lipoproteins clearance; increases lipogenic genes expression, which may partly contribute to abnormal blood lipid profiles.

Novel thyroid hormone analogues, enzyme inhibitors and mimetics, and their action

Thyroid hormones (THs) play key roles in modulating the overall metabolism of the body, protein synthesis, fat metabolism, neuronal and bone growth, and cardiovascular as well as renal functions. In this review, we discuss on the thyroid hormone synthesis and activation, thyroid hormone receptors (TRs) and mechanism of action, applications of thyroid hormone analogues, particularly the compounds that are selective ligands for TRβ receptors, or enzyme inhibitors for the treatment of thyroidal disorders with a specific focus on thyroid peroxidase and iodothyronine deiodinases. We also discuss on the development of small-molecule deiodinase mimetics and their mechanism of deiodination, as these compounds have the potential to regulate the thyroid hormone levels.

Antithyroid Drug Therapy for Graves' Disease and Implications for Recurrence

Graves' disease (GD) is the most common cause of hyperthyroidism worldwide. Current therapeutic options for GD include antithyroid drugs (ATD), radioactive iodine, and thyroidectomy. ATD treatment is generally well accepted by patients and clinicians due to some advantages including normalizing thyroid function in a short time, hardly causing hypothyroidism, and ameliorating immune disorder while avoiding radiation exposure and invasive procedures. However, the relatively high recurrence rate is a major concern for ATD treatment, which is associated with multiple influencing factors like clinical characteristics, treatment strategies, and genetic and environmental factors. Of these influencing factors, some are modifiable but some are nonmodifiable. The recurrence risk can be reduced by adjusting the modifiable factors as much as possible. The titration regimen for 12-18 months is the optimal strategy of ATD. Levothyroxine administration after successful ATD treatment was not recommended. The addition of immunosuppressive drugs might be helpful to decrease the recurrence rate of GD patients after ATD withdrawal, whereas further studies are needed to address the safety and efficacy. This paper reviewed the current knowledge of ATD treatment and mainly focused on influencing factors for recurrence in GD patients with ATD treatment.

Guidelines for the treatment of childhood-onset Graves' disease in Japan, 2016

Purpose behind developing these guidelines: Over one decade ago, the “Guidelines for the Treatment of Graves’ Disease with Antithyroid Drug, 2006” (Japan Thyroid Association (JTA)) were published as the standard drug therapy protocol for Graves’ disease. The “Guidelines for the Treatment of Childhood-Onset Graves’ Disease with Antithyroid Drug in Japan, 2008” were published to provide guidance on the treatment of pediatric patients. Based on new evidence, a revised version of the “Guidelines for the Treatment of Graves’ Disease with Antithyroid Drug, 2006” (JTA) was published in 2011, combined with the “Handbook of Radioiodine Therapy for Graves’ Disease 2007” (JTA). Subsequently, newer findings on pediatric Graves’ disease have been reported. Propylthiouracil (PTU)-induced serious hepatopathy is an important problem in pediatric patients. The American Thyroid Association’s guidelines suggest that, in principle, physicians must not administer PTU to children. On the other hand, the “Guidelines for the Treatment of Graves’ Disease with Antithyroid Drug, 2011” (JTA) state that radioiodine therapy is no longer considered a “fundamental contraindication” in children. Therefore, the “Guidelines for the Treatment of Childhood-Onset Graves’ Disease with Antithyroid Drug in Japan, 2008” required revision.

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum

BACKGROUND

Thyroid disease in pregnancy is a common clinical problem. Since the guidelines for the management of these disorders by the American Thyroid Association (ATA) were first published in 2011, significant clinical and scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid disease in women during pregnancy, preconception, and the postpartum period.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations. The guideline task force had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid disease in pregnancy include recommendations regarding the interpretation of thyroid function tests in pregnancy, iodine nutrition, thyroid autoantibodies and pregnancy complications, thyroid considerations in infertile women, hypothyroidism in pregnancy, thyrotoxicosis in pregnancy, thyroid nodules and cancer in pregnant women, fetal and neonatal considerations, thyroid disease and lactation, screening for thyroid dysfunction in pregnancy, and directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid disease in pregnant and postpartum women. While all care must be individualized, such recommendations provide, in our opinion, optimal care paradigms for patients with these disorders.

Efficacy of Once Daily versus Divided Daily Administration of Low Daily Dosage (15 mg/Day) of Methimazole in the Induction of Euthyroidism in Graves' Hyperthyroidism: A Randomized Controlled Study

BACKGROUND

Previous studies used unequal or high daily dosages of methimazole (MMI) to compare the efficacy of once daily dose regimen (OD-MMI) with that of divided daily doses regimen (DD-MMI) in inducing euthyroidism.

OBJECTIVES

To compare the efficacy of OD-MMI to that of DD-MMI using low daily dosage of MMI in inducing euthyroidism.

METHODS

Fifty patients with clinically nonsevere Graves' hyperthyroidism were randomized to be treated with 15 mg/day OD-MMI or 15 mg/day DD-MMI.

RESULTS

21 cases (84%) in OD-MMI and 23 cases (92%) in DD-MMI were eligible for analyses. During the treatment, there was no difference in baseline characteristics, serum FT3 and FT4 reductions, and cumulative rate of achieving euthyroidism (4.8% versus 4.3%, 28.6% versus 34.8%, 71.4% versus 82.6%, and 85.7% versus 87.0% at 2, 4, 8, and 12 weeks, resp.) between both regimens. Hypothyroidism developed in DD-MMI significantly more than in OD-MMI (17.4% versus 0%, p < 0.05).

CONCLUSIONS

Treatment with MMI at a low daily dosage of 15 mg/day OD-MMI is as effective as DD-MMI in the reduction of serum thyroid hormone levels and induction of euthyroidism. The OD-MMI regimen is preferable to the DD-MMI regimen in the treatment of clinically nonsevere Graves' hyperthyroidism. This trial is registered with Thai Clinical Trials Registry: TCTR20170529001.

2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis

BACKGROUND

Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This document describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspecialty physicians and others providing care for patients with this condition.

METHODS

The American Thyroid Association (ATA) previously cosponsored guidelines for the management of thyrotoxicosis that were published in 2011. Considerable new literature has been published since then, and the ATA felt updated evidence-based guidelines were needed. The association assembled a task force of expert clinicians who authored this report. They examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to update the 2011 text and recommendations. The strength of the recommendations and the quality of evidence supporting them were rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group.

RESULTS

Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' orbitopathy; and management of other miscellaneous causes of thyrotoxicosis. New paradigms since publication of the 2011 guidelines are presented for the evaluation of the etiology of thyrotoxicosis, the management of Graves' hyperthyroidism with antithyroid drugs, the management of pregnant hyperthyroid patients, and the preparation of patients for thyroid surgery. The sections on less common causes of thyrotoxicosis have been expanded.

CONCLUSIONS

One hundred twenty-four evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice.

Sudden onset agranulocytosis and hepatotoxicity after taking methimazole

Agranulocytosis is a rare adverse effect of methimazole. The usual duration of treatment prior to the onset of agranulocytosis is approximately 1 to 4 months, and can be as long as 1 year. Agranulocytosis together with hepatotoxicity is an extremely rare idiosyncratic side effect of methimazole treatment. We present an unprecedented case of a Grave's disease patient who showed a strong reaction to methimazole with obvious agranulocytosis and hepatotoxicity which developed only six days after administration. This case, along with a literature review, is offered with the aim to increase the awareness of physicians of sudden onset agranulocytosis and hepatotoxicity from methimazole.

Hyperthyroidism

Hyperthyroidism is a pathological syndrome in which tissue is exposed to excessive amounts of circulating thyroid hormone. The most common cause of this syndrome is Graves' disease, followed by toxic multinodular goitre, and solitary hyperfunctioning nodules. Autoimmune postpartum and subacute thyroiditis, tumors that secrete thyrotropin, and drug-induced thyroid dysfunction, are also important causes.<br /> <br />

Methimazole-induced hypothyroidism inhibits the panic-like behaviors produced by electrical stimulation of dorsal periaqueductal gray matter of rats

Conflicting clinical data on the relationship of panic disorder and thyroid diseases illustrate the need for a simpler approach using animal models. Defensive behaviors evoked by electrical or chemical stimulation of dorsal periaqueductal gray matter (DPAG) have been proposed as a model of panic attack. Therefore, the present study examined the effects of the anti-thyroid agent methimazole (MTZ) either on the panic-like behaviors induced by electrical stimulation of DPAG or the anxiety-like behaviors of rats exposed to the elevated plus-maze (EPM). Male Wistar rats bearing electrodes in the DPAG were stimulated with stepwise increased currents. Rats which displayed galloping at intensities below 60muA were retested following 5- and 10-day treatments with MTZ (0.6mg/kg/day, i.p.) or 10- and 15-day washout periods. MTZ effects on EPM performance were assessed in separate groups. MTZ-treated groups were compared to saline-treated controls. In other experiments, rats were similarly treated with MTZ and the blood was collected for hormone assays. The 10-day treatment with MTZ produced marked increases in the thresholds of exophthalmus (65%), immobility (75%), trotting (63%), galloping (56%), jumping (47%), defecation (114%) and micturition (85%). Effects outlasted the drug discontinuation. In contrast, MTZ had variable effects in the EPM, significantly increasing the open-arm exploration in 5-day treated and 10-day washout groups. Biochemical data revealed a small but significant decrease (13%) in free thyroxine in MTZ-treated groups. Although not significant, thyrotrophin levels showed a 111% increase following the 10-day treatment with MTZ. Selective attenuation by MTZ of DPAG-evoked defensive behaviors supports attenuation of panic attacks in hypothyroidism.

Current and emerging treatment options for Graves' hyperthyroidism

Radioiodine, antithyroid drugs and surgery have been well established therapies for Graves' hyperthyroidism for several decades. However there remain large variations in practice among physicians in the preferred modality and the method of administration. Patient choice and perceptions also play a big role in the choice of treatment. Radioiodine may be given using fixed high doses or by calculated doses following uptake studies. The risks of radioiodine including eye disease and the role of prophylactic steroid therapy are discussed. The commonly used antithyroid drugs include carbimazole, methimazole and propylthiouracil; however a number of other agents have been tried in special situations or in combination with these drugs. The antithyroid drugs may be given in high (using additional levothyroxine in a block-replace regimen) or low doses (in a titration regimen). This review examines the current evidence and relative benefits for these options as well as looking at emerging therapies including immunomodulatory treatments such as rituximab which have come into early clinical trials. The use of antithyroid therapies in special situations is also discussed as well as clinical practice issues which may influence the choices.

Antithyroid drug regimen for treating Graves' hyperthyroidism

BACKGROUND

Antithyroid drugs are widely used in the therapy of hyperthyroidism. There are wide variations in the dose, regimen or duration of treatment used by health professionals.

OBJECTIVES

To assess the effects of dose, regimen and duration of antithyroid drug therapy for Graves' hyperthyroidism.

SEARCH STRATEGY

We searched seven databases and reference lists.

SELECTION CRITERIA

Randomised and quasi-randomised trials of antithyroid medication for Graves' hyperthyroidism.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. Pooling of data for primary outcomes, and select exploratory analyses were undertaken.

MAIN RESULTS

Twenty-six randomised trials involving 3388 participants were included. Overall the quality of trials, as reported, was poor. None of the studies investigated incidence of hypothyroidism, changes in weight, health-related quality of life, ophthalmopathy progression or economic outcomes. Four trials examined the effect of duration of therapy on relapse rates, and when using the titration regimen 12 months was superior to six months, but there was no benefit in extending treatment beyond 18 months. Twelve trials examined the effect of block-replace versus titration block-regimens. The relapse rates were similar in both groups at 51% in the block-replace group and 54% in the titration block-group (OR 0.86, 95% confidence interval (CI) 0.68 to1.08) though adverse effects (rashes (10% versus 6%) and withdrawing due to side effects (16% versus 9%)) were significantly higher in the block-replace group. Three studies considered the addition of thyroxine with continued low dose antithyroid therapy after initial therapy with antithyroid drugs. There was significant heterogeneity between the studies and the difference between the two groups was not significant (OR 0.58, 95% CI 0.05 to 6.21). Four studies considered the addition of thyroxine alone after initial therapy with antithyroid drugs. There was no significant difference in the relapse rates between the groups after 12 months follow-up (OR 1.15, 95% CI 0.79 to 1.67). Two studies considered the addition of immunosuppressive agents. The results which were in favour of the interventions would need to be validated in other populations.

AUTHORS' CONCLUSIONS

The evidence suggests that the optimal duration of antithyroid drug therapy for the titration regimen is 12 to 18 months. The titration (low dose) regimen had fewer adverse effects than the block-replace (high dose) regimen and was no less effective. Continued thyroxine treatment following initial antithyroid therapy does not appear to provide any benefit in terms of recurrence of hyperthyroidism. Immunosuppressive therapies need further evaluation.

Hyperthyroidism

Thyrotoxicosis is a condition resulting from elevated levels of thyroid hormone. In this article, the authors review the presentation, diagnosis, and management of various causes of thyrotoxicosis.

Comparison of methimazole and propylthiouracil in patients with hyperthyroidism caused by Graves' disease

CONTEXT

Although methimazole (MMI) and propylthiouracil (PTU) have long been used to treat hyperthyroidism caused by Graves' disease (GD), there is still no clear conclusion about the choice of drug or appropriate initial doses.

OBJECTIVE

The aim of the study was to compare the MMI 30 mg/d treatment with the PTU 300 mg/d and MMI 15 mg/d treatment in terms of efficacy and adverse reactions.

DESIGN, SETTING, AND PARTICIPANTS

Patients newly diagnosed with GD were randomly assigned to one of the three treatment regimens in a prospective study at four Japanese hospitals.

MAIN OUTCOME MEASURES

Percentages of patients with normal serum free T(4) (FT4) or free T(3) (FT3) and frequency of adverse effects were measured at 4, 8, and 12 wk.

RESULTS

MMI 30 mg/d normalized FT4 in more patients than PTU 300 mg/d and MMI 15 mg/d for the whole group (240 patients) at 12 wk (96.5 vs. 78.3%; P = 0.001; and 86.2%, P = 0.023, respectively). When patients were divided into two groups by initial FT4, in the group of the patients with severe hyperthyroidism (FT4, 7 ng/dl or more, 64 patients) MMI 30 mg/d normalized FT4 more effectively than PTU 300 mg/d at 8 and 12 wk and MMI 15 mg/d at 8 wk, respectively (P < 0.05). No remarkable difference between the treatments was observed in patients with initial FT4 less than 7 ng/dl. Adverse effects, especially mild hepatotoxicity, were higher with PTU and significantly lower with MMI 15 mg/d compared with MMI 30 mg/d.

CONCLUSIONS

MMI 15 mg/d is suitable for mild and moderate GD, whereas MMI 30 mg/d is advisable for severe cases. PTU is not recommended for initial use.

Treatment for childhood-onset Graves' disease in Japan: results of a nationwide questionnaire survey of pediatric endocrinologists and thyroidologists

OBJECTIVE AND DESIGN

To determine the present condition of treatment of childhood-onset Graves' disease in Japan, a nationwide questionnaire survey was conducted among councilors of the Japanese Society for Pediatric Endocrinology and the Japan Thyroid Association.

MAIN OUTCOME

Responses were received from 125 individuals, and the rate of collection of questionnaires was 47%. Methimazole was selected for first-line initial antithyroid drug therapy by 92% of respondents. Antithyroid drugs tended to be given at larger initial doses and over longer periods of time to childhood-onset patients than to adult patients, and these tendencies were more pronounced for pediatric endocrinologists. Combination therapy with an antithyroid drug and thyroxine was used more frequently by pediatric endocrinologists. Thyroidologists had more experience with radioiodine therapy than pediatric endocrinologists. Opinions regarding preparation of guidelines for the initial dose of methimazole in childhood-onset Graves' disease were almost equally divided among the following: the dose of methimazole should be adjusted according to the severity of disease as in adult cases, methimazole should be started at a dose of 1mg/kg per day in all patients, and the dose should be determined based on results of a randomized study.

CONCLUSIONS

The present condition of treatment of childhood-onset Graves' disease in Japan was clarified.

Pharmacokinetics and Pharmacotherapy of Thionamides in Pregnancy

Hyperthyroidism occurs in approximately 1 in every 1000 to 2000 pregnancies. Although the signs and symptoms of the disease are similar in the pregnant and nonpregnant patient, the complications of hyperthyroidism can have even more profound consequences for the mother and fetus during gestation. These include maternal heart failure, preeclampsia, miscarriage, and preterm labor; as well as fetal loss and low birth weight. Furthermore, thyroid function and laboratory testing for hyperthyroidism are altered in pregnancy. The gestational increase in thyroid size, increased thyroid-binding globulin levels, increased serum total T4 and total T3 levels, and decreased thyroid stimulating hormone levels often confuses the evaluation of the thyroid status in pregnancy. Worldwide, the thionamides-propylthiouracil, methimazole, and carbimazole-have been used in pregnancy for the treatment of hyperthyroidism. However, propylthiouracil has been the drug of choice in the United States because it is believed to have less potential to induce fetal/neonatal hypothyrodism, to cross the placenta and into breast milk to a lesser degree, and to be less teratogenic than methimazole or carbimazole. None of the above have been substantiated in more recent studies. The pharmacokinetics of the thionamides in the pregnant and nonpregnant states, as well as the pharmacotherapeutic recommendation for hyperthyroidism will be reviewed.

The safety and efficacy of antithyroid drugs

Thionamides, selective inhibitors of thyroid peroxidase-mediated iodination by tyrosine residues in thyroglobulin, have been effectively used in the treatment of hyperthyroidism. The choices for initial treatment of patients with Graves' disease differ in various countries, and many physicians around the world prefer to administer thionamide drugs as the first choice of treatment for patients with hyperthyroidism. Although some thyroidologists more often consider radioiodine to be the treatment of choice because of its safety and ease of administration, thionamides remain the mainstay of treatment in thyrotoxic children and adolescents and in hyperthyroid women during pregnancy, postpartum period and lactation. A recent study with continuous thionamide treatment for patients with Graves' disease shows its efficacy, safety and cost-benefit properties. Further studies of the effectiveness of continuous thionamide therapy in patients with thyrotoxicosis need to be designed and implemented to determine indications for such therapy in children, adolescents and adults with diffuse toxic goiter, in particular, in those who have had recurrence of hyperthyroidism after discontinuation of one complete course of treatment.