methimazole and Cardiovascular-Diseases

Topics: Aged; Aged, 80 and over; Antithyroid Agents; Cardiovascular Diseases; Case-Control Studies; Cross-Over Studies; Diabetes Mellitus; Female; Gallstones; Graves Disease; Humans; Liver Diseases, Alcoholic; Male; Methimazole; Middle Aged; Pancreatitis; Prognosis; Risk Factors

Patients suffering from hypothyroidism tend to develop diastolic hypertension. 5-Hydroxytryptamine (5-HT) is an amine that contributes to the maintenance of the blood pressure through central and peripheral 5-HT receptors. Curiously, the hypothyroidism alters the density of the 5-HT receptors in rodent brains.. Analyze the effect of the methimazole-induced hypothyroidism on the peripheral cardiovascular responses elicited by 5-HT.. The vasopressor and tachycardic responses to 5-HT (3-300 μg/kg), and the vasodepressor responses to 5-HT, 5-carboxamidotryptamine (5-CT, 0.001-0.1 μg/kg), isoprenaline (0.03-1 μg/kg) and acetylcholine (ACh, 0.03-3 μg/kg), during an infusion of methoxamine, were determined in pithed hypothyroid rats.. The tachycardic and vasopressor responses to 5-HT and the vasodepressor responses to 5-CT and ACh remained unaffected, the vasodepressor response to 5-HT reduced, and the vasodepressor response to isoprenaline enhanced and reduced at the lowest and highest dose, respectively.. These results suggest that hypothyroidism impairs the vasodepressor response to 5-HT, which could contribute to hypothyroidism-induced hypertension.

Topics: Animals; Cardiovascular Diseases; Hypothyroidism; Male; Methimazole; Rats; Rats, Wistar; Serotonin

Thyroid hormones have many effects on cardiovascular function, and deficiency or excess of thyroid hormones can result in cardiac dysfunction. Abnormalities of the cardiovascular system are often identified during examination of hyperthyroid and hypothyroid patients. This article addresses the effects of thyroid hormones on the cardiovascular system and the clinical relevance of the cardiovascular response to thyroid dysfunction. In addition, treatment recommendations are presented.

Topics: Animals; Antithyroid Agents; Cardiovascular Diseases; Cat Diseases; Cats; Dog Diseases; Dogs; Hyperthyroidism; Hypothyroidism; Methimazole; Thyroxine

A case is reported of neoplastic TSH hypersecretion in a 62-year-old man with severe hyperthyroidism and cardiovascular disease. He had been known to be hyperthyroid for 14 yr, and had been treated by thyreostatic drugs and subtotal thyroidectomy without satisfactory results. When he was referred to our Center, he was frankly hyperthyroid with both TSH (14 microU/ml) and thyroid hormone serum levels (TT4 24 micrograms/dl, TT3 370 ng/dl, FT41 7.9) above the normal range. alpha-subunit serum level was markedly increased (7.2 ng/ml), while beta-subunit was only 0.3 ng/ml. Skull X-ray showed an enlarged sella turcica with destruction of the dorsum and an intrasellar tumor was visualized on conventional and computer tomography. TSH response was absent after TRH and domperidone, while TSH serum levels decreased by 25% after bromocriptine. Methimazole therapy temporarily decreased serum thyroid hormones to normal levels, while TSH levels rose to 34 microU/ml, thus indicating that pituitary-thyroid feed-back was maintained at a higher set point. Surgical attempt failed because of cardiac problems during anesthesia. Radiotherapy plus methimazole was begun and TSH serum levels first increased markedly, up to 140 microU/ml, and then progressively decreased without reaching normal values. After methimazole withdrawal hyperthyroidism recurred.

Topics: Bromocriptine; Cardiovascular Diseases; Humans; Hyperthyroidism; Male; Methimazole; Middle Aged; Pituitary Gland; Pituitary Neoplasms; Thyrotropin; Thyroxine; Triiodothyronine