methimazole / Generic mfg. - LARVOL DELTA

Species-specific sensitivity to in vitro inhibition of the thyroperoxidase (TPO) enzyme by environmental pollutants for five fishes. (PubMed, Environ Toxicol Chem) - "The reference inhibitor, methimazole, and five environmentally relevant chemicals were evaluated to represent a range of potencies reported in the ToxCast mammalian-based assays...This sensitivity was consistent across phylogenetically diverse species and is supported by the high level of conservation of TPO structure and function across vertebrate taxa. Taken together, these findings suggest that toxicity data from model fishes can be extrapolated to native species and mammalian-based ToxCast data can confidently be used as a source for predicting relative potencies of chemicals for inhibiting TPO of fishes in support of more objective ecological risk assessments."

Journal • Preclinical

Beyond DILI: A Case of Secondary HLH Presenting as Refractory Cholestatic Liver Injury (ACG 2026) - "We report a case of suspected secondary HLH initially attributed to persistent methimazole-induced cholestatic drug-induced liver injury (DILI)...Given progressive clinical decline and persistent hyperinflammation, HLH-directed dexamethasone therapy was initiated...Figure: Figure 1. Clinical progression leading to the diagnosis of secondary HLH"

Clinical • Acute Kidney Injury • Dyslipidemia • Endocrine Disorders • Hematological Disorders • Hemophagocytic lymphohistiocytosis • Hepatology • Hypertriglyceridemia • Immunology • Inflammation • Liver Failure • Nephrology • Pruritus • Rare Diseases • Renal Disease • IL2

Fulminant Thyrotoxicosis-induced Cholestatic Liver Failure: Navigating Thyroid Management Amid Hepatotoxic Risk (ACG 2026) - "The patient was treated with methimazole, propranolol, corticosteroids, lactulose, rifaximin, antimicrobials, and hemodialysis...Management includes hemodynamic stabilization, beta-blockade, corticosteroids, and careful antithyroid selection, with methimazole preferred over propylthiouracil in significant liver dysfunction...Figure: Figure 2. Long-axis ultrasound of the right hepatic lobe showing gallbladder wall thickening and sludge without biliary ductal dilation, consistent with cholestatic changes."

Acute Kidney Injury • Atrial Fibrillation • Autoimmune Hepatitis • Cardiovascular • CNS Disorders • Endocrine Disorders • Hematological Disorders • Hepatology • Immunology • Infectious Disease • Inflammation • Liver Failure • Nephrology • Renal Disease • Respiratory Diseases • Thrombocytopenia

Acute Pancreatitis Following Methimazole Dose Escalation in Gravesâ Disease: A Rare Adverse Drug Reaction (ACG 2026) - "She was transitioned to propylthiouracil for management of hyperthyroidism with rapid clinical improvement. Application of the Naranjo Adverse Drug Reaction Probability Scale yielded a score of 6, consistent with a probable medicationârelated reaction. Clinicians should recognize methimazole as a rare cause of acute pancreatitis, particularly following recent initiation or dose escalation."

Adverse drug reaction • Dyslipidemia • Endocrine Disorders • Gastroenterology • Grave’s Disease • Hypertriglyceridemia • Infectious Disease • Inflammation • Mood Disorders • Pancreatitis • Severe Hypertriglyceridemia

Acute Liver Failure in Thyroid Storm: A Multifactorial Hepatic Injury in the Setting of Gravesâ Disease and Cardiogenic Shock (ACG 2026) - "Thyroid storm was diagnosed clinically, and treatment with methimazole, beta-blockade, glucocorticoids, and cholestyramine was initiated...She was managed supportively, including N-acetylcysteine...Thyroid storm should be considered in patients with unexplained ALF and cardiovascular instability, as early recognition and multidisciplinary management may improve outcomes even in severe multisystem disease. Figure: Timeline of Clinical Events"

Cardiovascular • Chronic Kidney Disease • CNS Disorders • Congestive Heart Failure • Coronary Artery Disease • Endocrine Disorders • Grave’s Disease • Heart Failure • Hepatic Encephalopathy • Hepatology • Inflammation • Liver Failure • Myocardial Infarction • Renal Disease

Graves disease complicated by agranulocytosis and thrombocytopenia in a 12-year-old girl. (PubMed, JCEM Case Rep) - "Blood cell counts remained within the normal range thereafter, and thyroid function has remained well controlled with methimazole monotherapy. This case suggests that thyrotoxicosis itself is associated with cytopenia and provides valuable insight for clinicians when selecting a therapeutic strategy for Graves disease complicated by cytopenia."

Journal • Agranulocytosis • Endocrine Disorders • Granulocytopenia • Grave’s Disease • Hematological Disorders • Neutropenia • Pediatrics • Thrombocytopenia

Refractory Graves' Disease With Propylthiouracil-Induced Hemophagocytic Lymphohistiocytosis and Multiple Drug Allergies Treated With Total Thyroidectomy: A Case Report. (PubMed, Cureus) - "Methimazole (MMI) and propylthiouracil (PTU) are commonly used, sometimes with adjunctive agents such as potassium iodide (KI), β-blockers, or corticosteroids...Due to multiple drug allergies, a drug-induced lymphocyte stimulation test was performed preoperatively and was positive for levothyroxine (LT4), although patch and oral provocation tests were negative, confirming LT4 safety...The course was uneventful, without allergic manifestations, and she was discharged in good condition. This case highlights the risk of severe hematologic complications from PTU and demonstrates that, with careful preoperative evaluation and individualized perioperative management, safe surgical treatment of refractory Graves' disease is possible."

Journal • Allergy • Endocrine Disorders • Fatigue • Grave’s Disease • Hematological Disorders • Hemophagocytic lymphohistiocytosis • Immunology • Rare Diseases

Targeting glioma stem cells with thyroid hormone suppression: Phase 1/2 trial of methimazole in patients with progressive grade 4 gliomas. (ASCO 2024) - P2 | "Patients may have had unlimited prior regimens including bevacizumab. In this early cohort, it appears methimazole treatment in recurrent GBM patients enhances HPC on a systemic level. Next steps will be to measure sulfide signaling and sulfhydration alterations in patient tumor samples. The protocol is being modified to allow earlier addition (2 weeks) of post-op chemotherapy."

Clinical • P1/2 data • Brain Cancer • CNS Tumor • Endocrine Disorders • Glioblastoma • Glioma • Oncology • Solid Tumor

Pazopanib-associated destructive thyroiditis mimicking thyroid malignancy on ultrasound (ETA 2026) - "Antithyroid treatment with methimazole was briefly initiated; however, thyroid function rapidly evolved towards hypothyroidism, leading to treatment withdrawal...Thyroid function stabilised under levothyroxine replacement therapy, which is currently maintained...This case highlights the importance of recognising drug-associated destructive thyroiditis as a potential mimic of thyroid cancer. Careful correlation between clinical context, biochemical findings and serial imaging may support a conservative management strategy and help avoid unnecessary invasive diagnostic procedures."

Anorexia • Endocrine Disorders • Genito-urinary Cancer • Musculoskeletal Pain • Oncology • Papillary Renal Cell Carcinoma • Renal Cell Carcinoma • Solid Tumor • Thyroid Gland Carcinoma

A smartphone-assisted colorimetric sensor for sensitive and portable sensing of methimazole based on high-entropy Prussian blue nanozymes. (PubMed, Spectrochim Acta A Mol Biomol Spectrosc) - "Moreover, this colorimetric sensor has been successfully applied for MMI detection in commercial cosmetic samples, demonstrating its potential practicality. This work not only provides a cheap, user-friendly, and portable sensing platform for visual detection of MMI in resource-limited settings, but also offers a rational design strategy for HEzymes."

Journal

Hypokalemic paralysis complicated by Takotsubo cardiomyopathy in an euthyroid elderly male with Graves' disease during methimazole dose reduction. (PubMed, J Geriatr Cardiol) - No abstract available

Journal • Cardiomyopathy • Cardiovascular • Endocrine Disorders • Grave’s Disease

Antibody Negative Thyrotoxicosis Treated with Methimazole: A Diagnostic Pitfall of Destructive Thyroiditis (ATA 2026) - No abstract available

Endocrine Disorders

Methimazole-associated antithyroid arthritis syndrome a rare side effect: A Case Report (ATA 2026) - No abstract available

Adverse events • Case report • Clinical • Immunology • Rheumatology

Persistent Severe Thyrotoxicosis despite High-Dose Methimazole in Graves Disease: When Medical Therapy Fails (ATA 2026) - No abstract available

Endocrine Disorders • Grave’s Disease

Infection Associated Transient Neutropenia Mimicking Methimazole Induced Agranulocytosis (ATA 2026) - No abstract available

Agranulocytosis • Granulocytopenia • Hematological Disorders • Infectious Disease • Neutropenia

Poly-Etiology Liver Injury in an Elderly Woman: Interplay of Methimazole Toxicity, Autoimmune Markers, Iron Deposition, and Cardiac Hepatopathy (ATA 2026) - No abstract available

Clinical • Hepatology • Immunology • Liver Failure

JAUNDICE AND JUDICIOUS DOSING: A CASE OF METHIMAZOLE-INDUCED LIVER FAILURE (CHEST 2026) - No abstract available

Clinical • Hepatology • Liver Failure

Comparative transcriptomics reveals a core molecular signature of hypothyroid testis development across three TPO inhibitors. (PubMed, Ecotoxicol Environ Saf) - "Here, we build on previous work to define a molecular signature in testes from hypothyroid rats induced by three thyroperoxidase (TPO)-inhibiting chemicals: the pharmaceuticals propylthiouracil (PTU), and methimazole (MMI), and the pesticide amitrole (AMI). The shared transcriptional changes were associated with biological processes related to cell cycle regulation, developmental growth, and pathways involved in Sertoli cell proliferation, germ cell development, and testis morphogenesis. Collectively, these findings support the existence of a TH-mediated molecular signature that aligns with the classical morphologic phenotype of hypothyroid testis and underscores its potential value for the development of alternative, mechanism-based test methods for regulatory purposes."

Journal • Endocrine Disorders

TRPV1-STAT3 signaling as a driver of lethal pathology during pneumococcal nose-to-brain invasion. (PubMed, Microbiol Spectr) - "A murine intranasal infection model using Streptococcus pneumoniae was established with methimazole-induced olfactory epithelial damage and/or resiniferatoxin-mediated trigeminal TRPV1 ablation...These findings suggest that targeting host responses, rather than the bacteria alone, may mitigate severe complications of pneumococcal infection. This study provides new insight into the contribution of sensory systems to infection outcomes and highlights potential strategies for therapeutic intervention."

Journal • Infectious Disease • Inflammation • Otorhinolaryngology • Pneumococcal Infections • Pneumonia • Respiratory Diseases • TRPV1

Transition from Hashimoto's Thyroiditis to Graves' Disease: A Case Report (ETA 2026) - "Treatment with methimazole (20 mg/day) was initiated, leading to clinical improvement and normalization of FT4 and FT3 after eight weeks. Conversion from Hashimotos thyroiditis to Graves disease is an uncommon but clinically important phenomenon. This case highlights the need to consider this transition in patients with autoimmune hypothyroidism who require progressive reduction or discontinuation of levothyroxine therapy. Measurement of TRAb may help establish the diagnosis and guide appropriate management."

Case report • Clinical • Cardiovascular • Developmental Disorders • Endocrine Disorders • Genetic Disorders • Grave’s Disease • Immunology

Methimazole-Induced Agranulocytosis: A Case Report (ETA 2026) - "Treatment was initiated with piperacillin/tazobactam, filgrastim, and propylthiouracil (PTU) 200 mg every 8h, and methimazole was discontinued...PTU was discontinued, and propranolol 10 mg every 8h, hydrocortisone 100 mg every 8h, and cholestyramine 4 g every 8h were initiated... Routine monitoring of leukocyte counts is not recommended, as agranulocytosis occurs abruptly. Given its potential severity, it is essential to inform patients about warning signs and symptoms at the initiation of treatment with thionamides."

Case report • Clinical • Agranulocytosis • Dysphonia • Endocrine Disorders • Febrile Neutropenia • Gastrointestinal Disorder • Granulocytopenia • Grave’s Disease • Hematological Disorders • Infectious Disease • Leukopenia • Mood Disorders • Neutropenia • Otorhinolaryngology

Refractory Amiodarone-Induced Thyrotoxicosis Treated with Total Thyroidectomy: A Case Report (ETA 2026) - "Initial treatment included methimazole 20 mg/day, prednisolone 20 mg/day, and propranolol. This case illustrates the clinical challenge of refractory type 2 AIT. Although glucocorticoids usually restore euthyroidism, some cases have a prolonged course, particularly those with severe thyrotoxicosis at presentation. Restoration of sinus rhythm is unlikely until euthyroidism is achieved, and prolonged exposure to thyroid hormone excess increases cardiovascular morbidity."

Case report • Clinical • Atrial Fibrillation • Cardiovascular • CNS Disorders • Depression • Endocrine Disorders • Hypertension • Movement Disorders

Skin Rash Following Initiation of Methimazole Therapy: A Diagnostic and Management Challenge in Graves’ Disease (ETA 2026) - "Treatment with methimazole, propranolol and insulin were initiated, and the patient was subsequently followed in the endocrinology clinic with progressive adjustment of insulin and methimazole dosages...Suspecting a hypersensitivity reaction to methimazole, treatment was switched to propylthiouracil until October 2025. During this period, she reported persistent pruritus without maculopapular lesions, leading to the switch back to methimazole with concomitant therapy with bilastine... Chronic spontaneous urticaria is commonly linked to underlying autoimmune conditions, particularly autoimmune thyroid disease, and may resemble antithyroid drug hypersensitivity, complicating the management of Graves disease. Therefore, the onset of urticaria after starting antithyroid drug therapy should not be automatically interpreted as drug hypersensitivity, and alternative diagnoses should be considered. This case emphasizes the importance of a multidisciplinary approach to ensure..."

Chronic Spontaneous Urticaria • Dermatology • Diabetes • Endocrine Disorders • Grave’s Disease • Immunology • Metabolic Disorders • Pruritus • Urticaria

Painless subacute Thyroiditis During treatment of Graves deasese Mimicking antithyroid Therapy (ETA 2026) - "Case Report: A 41-year-old woman with Graves disease started Methimazole therapy, showing initial clinical and biochemical improvement... Subacute thyroiditis can occur during treatment of Graves disease and may mimic treatment failure due to worsening thyrotoxicosis. Atypical presentations without neck pain can complicate diagnosis. Awareness of this overlap is critical for timely recognition, avoiding misdiagnosis, and ensuring appropriate management."

Endocrine Disorders • Grave’s Disease • Infectious Disease • Musculoskeletal Pain

Dual Etiology of Hyperthyroidism: A Case of Marine–Lenhart Syndrome (ETA 2026) - "The patient was started on methimazole and beta-blocker therapy... This case demonstrates Graves disease with a concomitant toxic adenoma, a rare form of hyperthyroidism known as MarineLenhart syndrome. Recognition of MLS can be challenging because of its overlapping clinical and biochemical features with other causes of hyperthyroidism. However, accurate diagnosis is crucial, as patients often exhibit a suboptimal response to antithyroid drug therapy and frequently require definitive treatment options such as surgery or RAI, underscoring the importance of comprehensive diagnostic evaluation to guide appropriate management and optimize patient outcomes."

Clinical • Alopecia • Cardiovascular • Endocrine Disorders • Grave’s Disease • Hypertension • Movement Disorders