Association Between Thionamides and Acute Pancreatitis: A Case-Control Study

Background: Thionamides have been extensively used to treat patients with hyperthyroidism worldwide. Recent pharmacovigilance studies have revealed a safety signal between carbimazole or methimazole and pancreatitis. The associated risk remains unclear. Methods: We identified patients with newly diagnosed acute pancreatitis from 2000 to 2013 as the case group from the Taiwan Longitudinal Health Insurance Database 2000, which contains data from 1996 to 2013. Each patient with acute pancreatitis was matched for age, sex, comorbidities, and cancer with four controls through propensity score matching. A total of 52 patients without matched controls were excluded. Sensitivity analyses including the 52 excluded patients were performed using a matching ratio of 1:2. Odds ratios (ORs) along with 95% confidence intervals (CIs) for the association were estimated using multivariate logistic regression. Results: We included 9204 and 36,816 patients in the case and control groups, respectively. The proportions of patients who had used thionamides, carbimazole, methimazole, and propylthiouracil were similar in these two groups. In addition, the adjusted OR (CI) for the association of acute pancreatitis with thionamides was 1.03 (0.86-1.24), with carbimazole it was 0.90 (0.63-1.30), with methimazole it was 1.05 (0.84-1.31), and with propylthiouracil it was 1.00 (0.74-1.34). The sensitivity analysis results were unchanged. Conclusions: We were unable to demonstrate an association between acute pancreatitis and usage of thionamides.

Oral TNFα Modulation Alters Neutrophil Infiltration, Improves Cognition and Diminishes Tau and Amyloid Pathology in the 3xTgAD Mouse Model

Cytokines such as TNFα can polarize microglia/macrophages into different neuroinflammatory types. Skewing of the phenotype towards a cytotoxic state is thought to impair phagocytosis and has been described in Alzheimer’s Disease (AD). Neuroinflammation can be perpetuated by a cycle of increasing cytokine production and maintenance of a polarized activation state that contributes to AD progression. In this study, 3xTgAD mice, age 6 months, were treated orally with 3 doses of the TNFα modulating compound isoindolin-1,3 dithione (IDT) for 10 months. We demonstrate that IDT is a TNFα modulating compound both in vitro and in vivo. Following long-term IDT administration, mice were assessed for learning & memory and tissue and serum were collected for analysis. Results demonstrate that IDT is safe for long-term treatment and significantly improves learning and memory in the 3xTgAD mouse model. IDT significantly reduced paired helical filament tau and fibrillar amyloid accumulation. Flow cytometry of brain cell populations revealed that IDT increased the infiltrating neutrophil population while reducing TNFα expression in this population. IDT is a safe and effective TNFα and innate immune system modulator. Thus small molecule, orally bioavailable modulators are promising therapeutics for Alzheimer’s disease.

Comparison of mortality in hyperthyroidism during periods of treatment with thionamides and after radioiodine

CONTEXT

Hyperthyroidism is common, but opinions regarding optimal therapy with antithyroid drugs or radioiodine (131-I) differ. There are no randomized trials comparing these options in terms of mortality.

OBJECTIVE

The aim of the study was to determine whether mortality associated with hyperthyroidism varies with treatment administered or other factors.

DESIGN, SETTING, AND PATIENTS

We conducted a prospective observational population-based study of 1036 subjects aged ≥ 40 years presenting to a single specialist clinic from 1989-2003 with a first episode of hyperthyroidism who were followed until June 2012.

INTERVENTIONS

Antithyroid drugs or radioiodine (131-I) were administered.

MAIN OUTCOME MEASURES

We compared causes of death with age-, sex-, and period-specific mortality in England and Wales and used within-cohort analysis of influence of treatment modality, outcome, disease etiology, severity and control, and comorbidities.

RESULTS

In 12 868 person-years of follow-up, 334 died vs 290.6 expected (standardized mortality ratio [SMR], 1.15 [95% confidence interval (CI),1.03-1.28]; P = .01). Increased all-cause mortality largely reflected increased circulatory deaths (SMR, 1.20 [95% CI, 1.01-1.43]; P = .04). All-cause mortality was increased for the person-years accumulated during thionamide treatment (SMR, 1.30 [95% CI, 1.05-1.61]; P = .02) and after 131-I not associated with hypothyroidism (SMR, 1.24 [95% CI, 1.04-1.46]; P = .01) but not during T₄ replacement for 131-I-induced hypothyroidism (SMR, 0.98 [95% CI, 0.82-1.18]; P = .85). Within-cohort analysis comparing mortality during thionamide treatment showed a similar hazard ratio (HR) for all-cause mortality when 131-I did not result in hypothyroidism (HR, 0.95 [95% CI, 0.70-1.29]), but reduced mortality with 131-I-induced hypothyroidism (HR, 0.70 [95% CI, 0.51-0.96]). Reduced mortality associated with hypothyroidism was seen only in those without significant comorbidities and not in those with other serious diseases. Atrial fibrillation at presentation (P = .02) and an increment of 10 pmol/L in serial free T₄ concentration during follow-up (P = .009) were independently associated with mortality.

CONCLUSIONS

Among hyperthyroid subjects aged 40 years or older, mortality was increased during periods of thionamide treatment and after radioiodine not resulting in hypothyroidism, but not during follow-up after radioiodine-induced hypothyroidism. Independent associations of mortality with atrial fibrillation and incomplete biochemical control during treatment indicate potential causative links with poor outcome.

Extrathyroidal actions of antithyroid thionamides

Some compounds having thionamide structure inhibit thyroid functions. Such antithyroid thionamides include mercaptomethylimidazole (methimazole), thiourea and propylthiouracil, of which mercaptomethylimidazole is widely used to treat hyperthyroidism. Undesirable side effects develop from these drugs due to extrathyroidal actions. Antithyroid thionamides inhibit lactoperoxidase which contributes to the antibacterial activities of a number of mammalian exocrine gland secretions that protect a variety of mucosal surfaces. These drugs stimulate both gastric acid and pepsinogen secretions, thereby augmenting the severity of gastric ulcers and preventing wound healing. Increased gastric acid secretion is partially due to the H2 receptor activation, and also through the stimulation of the parietal cell by intracellular generation of H2O2 following inactivation of the gastric peroxidase-catalase system. Severe abnormalities may develop in blood cells and the immune system after thionamide therapy. It causes agranulocytosis, aplastic anemia, and purpura along with immune suppression. Olfactory and auditory systems are also affected by these drugs. Thionamide affects the sense of smell and taste and also causes loss of hearing. It binds to the Bowman's glands in the olfactory mucosa and causes extensive lesion in the olfactory mucosa. Thionamides also affect gene expression and modulate the functions of some cell types. A brief account of the chemistry and metabolism of antithyroid thionamides, along with their biological actions are presented.

Hepatitis in leprosy patients treated by a daily combination of dapsone, rifampin, and a thioamide

A 13% incidence of hepatitis was observed among 54 cases of multibacillary leprosy treated daily with the three-drug combination of dapsone, rifampin, and a thioamide (ethionamide or prothionamide). No hepatitis was observed among 109 cases of paucibacillary leprosy treated daily with the two-drug combination of dapsone and rifampin. Symptoms were jaundice in five cases and nausea plus vomiting associated with a significant increase of transaminase levels in two cases. In five cases, the symptoms appeared during the first two months of therapy and in two cases, later. Discontinuing treatment with rifampin and the thioamide but not dapsone resulted in recovery. When rifampin was resumed without the thioamide, the hepatitis did not recur. Viral etiology could be eliminated in six cases. Neither sex, age, weight nor the fact that the patient was a new case or a relapse case appeared to be a contributing factor. Hepatotoxicity caused by administration of a thioamide might have been potentiated by the concurrent administration of rifampin.