digoxin and Hypothyroidism

Topics: Digitalis Glycosides; Digitoxin; Digoxin; Drug Interactions; Heart Failure; Humans; Hyperthyroidism; Hypothyroidism; Intestinal Absorption; Kidney Failure, Chronic; Molecular Conformation; Obesity

Cardiovascular diseases and their treatment in the aged are discussed under the headings of ischemic heart disease, hypertension, cardiac failure (with special reference to the use of diuretics and digoxin), infective carditis and thyroid disorders. Advanced age modifies the approach to treatment; the choice of drugs and the dosage must be adjusted accordingly. Possible drug interactions should also be considered. A rehabilitation program is of great benefit for many elderly cardiac patients. It should be planned individually and involve psychologic and environmental factors as well as medical therapy. After successful treatment of the acute episode, even the aged patient can undertake rewarding activities in his remaining lifetime.

Topics: Adrenergic beta-Antagonists; Aged; Anti-Bacterial Agents; Arrhythmias, Cardiac; Benzothiadiazines; Cardiac Rehabilitation; Cardiac Surgical Procedures; Cardiovascular Diseases; Coronary Disease; Delayed-Action Preparations; Digoxin; Diuretics; Endocarditis; Female; Heart Failure; Humans; Hypertension; Hypertension, Malignant; Hyperthyroidism; Hypothyroidism; Isosorbide Dinitrate; Male; Methyldopa; Middle Aged; Nitroglycerin; Sodium Chloride Symporter Inhibitors

Serum digoxin concentrations were measured by radioimmunoassay in 17 hyperthyroid and 16 hypothyroid patients after a seven-day course of oral digoxin. The significantly higher levels of serum digoxin in patients with hypothyroidism and lower levels in those with hyperthyroidism were closely related to the measured changes of glomerular filtration rate and digoxin serum half time in these two groups. Differences in serum digoxin concentration contribute to the altered sensitivity to digoxin shown by patients with thyroid disease.

Topics: Administration, Oral; Adult; Clinical Trials as Topic; Creatinine; Digoxin; Female; Glomerular Filtration Rate; Half-Life; Humans; Hyperthyroidism; Hypothyroidism; Male; Middle Aged; Thyroid Diseases; Time Factors

Topics: Adrenergic beta-Antagonists; Aged; Amiodarone; Atrial Fibrillation; Bisoprolol; Bradycardia; Calcium Channel Blockers; Cardiovascular Agents; Combined Modality Therapy; Digoxin; Diltiazem; Female; Humans; Hypothyroidism; Kidney Failure, Chronic; Myocardial Infarction; Pacemaker, Artificial; Renal Dialysis

The impact of thyroid dysfunction on the regulation, expression, and function of ABCB1 remains unclear. We therefore investigated ABCB1 mRNA expression and function in patients with thyroid dysfunction and studied the disposition of the ABCB1 substrate digoxin before and after treatment for thyroid disease. In patients with hypothyroidism, normalization of thyroid function was associated with a 1.8-fold increase in mRNA expression and a 26% increase in rhodamine efflux from CD56(+) cells. In hypothyroidism, digoxin clearance was significantly decreased, whereas bioavailability, volume of distribution, half-life time, and protein binding were unaltered. In hyperthyroidism, ABCB1 mRNA expression, rhodamine efflux, and disposition of digoxin were not significantly affected other than in relation to renal clearance. Experiments using the LS174T cell line indicated that the gene is a direct target of thyroid hormone receptors. In conclusion, thyroid abnormalities can exert significant effects on the expression of P-glycoprotein, thereby altering the disposition and action of drugs that are substrates of P-glycoprotein.

Topics: Administration, Oral; Adult; Aged; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Caco-2 Cells; Cardiotonic Agents; Digoxin; Enhancer Elements, Genetic; Female; Gene Expression Regulation; Humans; Hyperthyroidism; Hypothyroidism; Infusions, Intravenous; Male; Middle Aged; Rhodamines; RNA, Messenger; Thyroid Hormones; Transfection; Young Adult

The primary cause of cardiac dysfunction in thalassemia is believed to be myocardial iron overload. Besides iron, other factors may play a role in the impairment of myocardial contractility, including prolonged heart tissue hypoxia, pericardial involvement, arrhythmias, endocrine complications and vitamin D deficiency. We present the case of a 7 year-old boy with ?-thalassaemia major and cardiac dysfunction, pericardial effusion and associated endocrinopathies. His serum thyrotropin (TSH) level was increased, and total and free thyroxine (FT4) were low. In addition, biochemical results and serum PTH level were compatible with a diagnosis of hypoparathyroidism. Other laboratory findings were not consistent with rheumatic heart disease, viral myocarditis or autoimmune disease. The child was treated with digoxin, diuretics, oral calcium, vitamin D, L-thyroxine (25 microg daily, which was later gradually increased) and subcutaneous iron chelation therapy (45 mg/kg, six days/week). The patient was discharged from our Unit after 7 days and within 3 months he had appreciable myocardial improvement and disappearance of the pericardial effusion.

Topics: beta-Thalassemia; Calcium; Cardiomyopathies; Cardiotonic Agents; Child; Digoxin; Diuretics; Humans; Hypoparathyroidism; Hypothyroidism; Iron Chelating Agents; Iron Overload; Male; Pericardial Effusion; Thyroxine

Topics: Adult; Amiodarone; Anti-Arrhythmia Agents; Child; Cranial Nerve Neoplasms; Digoxin; Down Syndrome; Ductus Arteriosus, Patent; Facial Nerve; Facial Paralysis; Female; Heart Defects, Congenital; Heart Septal Defects, Atrial; Humans; Hypothyroidism; Infant, Newborn; Male; Neurilemmoma; Transposition of Great Vessels

We present a case of persistent fetal supraventricular tachycardia where transplacental and direct fetal treatment with amiodarone caused an iatrogenic hypothyroidism. This condition was successfully managed with the intra-amniotic instillation of 250 micrograms of L-thyroxine weekly, for 3 weeks. A male infant was delivered at 32 weeks by Caesarean section. The neonatal electrocardiogram showed Wolf-Parkinson-White (WPW) syndrome, which was controlled by digoxin alone. Thyroid function normalized quickly and the baby is developing normally.

Topics: Adult; Amiodarone; Digoxin; Female; Fetal Diseases; Humans; Hypothyroidism; Infant, Newborn; Male; Pregnancy; Tachycardia, Supraventricular; Thyroxine; Wolff-Parkinson-White Syndrome

Topics: Aged; Digoxin; Female; Humans; Hypothyroidism; Medication Errors; Patient Compliance; Self Administration; Thyroxine

Topics: Aged; Atrial Flutter; Digoxin; Female; Humans; Hypothyroidism; Poisoning; Risk Factors

1. Urinary excretion of digoxin-like immunoreactive factor and arginine-vasopressin and other parameters related to salt and water metabolism were studied in hyper- and hypo-thyroid rats after different tests. 2. Urinary excretion of arginine-vasopressin was increased in hyperthyroid and reduced in hypothyroid rats with respect to controls, in response to water deprivation or a hypertonic saline load. 3. Control and hypothyroid rats showed the highest urinary excretion of digoxin-like immunoreactive factor after a hypertonic saline load. However, hyperthyroid rats had the highest urinary levels of digoxin-like immunoreactive factor under normal conditions. 4. From these results it is suggested that: (a) hyper- and hypo-thyroid rats exhibit hyper- and hypo-responsiveness of arginine-vasopressin secretion to osmotic stimuli, respectively; (b) an unidentified digoxin-like immunoreactive factor measured in unextracted rat urine may be related to diuresis and natriuresis in control and hypothyroid rats; however, dissociation between this factor and natriuresis is observed in hyperthyroid rats.

Topics: Animals; Arginine Vasopressin; Blood Proteins; Cardenolides; Digoxin; Hyperthyroidism; Hypothyroidism; Kidney; Male; Methimazole; Rats; Rats, Inbred Strains; Saline Solution, Hypertonic; Saponins; Sodium-Potassium-Exchanging ATPase; Thyroxine; Water Deprivation

The problem of a possible interaction between amiodarone and digoxin is still unsettled. We have recently treated two patients with digoxin intoxication who had received amiodarone for eight and 36 months respectively. Both developed extreme bradycardia requiring temporary pacemakers. The presence of hypothyroidism was confirmed in both cases by laboratory data. Judging by present knowledge concerning the interaction between amiodarone, thyroid function, and digoxin, it is suggested that digoxin intoxication was not the result of its direct interaction with amiodarone. The possibility that amiodarone-induced hypothyroidism precipitated digoxin intoxication seems to be more plausible. Prevention of digitalis toxicity in amiodarone-treated patients would therefore require monitoring of thyroid function every three to six months. Frequent monitoring of digitalis blood levels is also indicated in patients with amiodarone associated hypothyroidism. Early detection of hypothyroidism and digitalis intoxication is necessary in view of the severity of the course of the disease.

Topics: Aged; Amiodarone; Benzofurans; Bradycardia; Digoxin; Drug Interactions; Electrocardiography; Female; Heart Block; Humans; Hypothyroidism; Male

Topics: Amiodarone; Benzofurans; Digoxin; Drug Interactions; Humans; Hypothyroidism

In a comparative prospective study the serum levels of digoxin and digitoxin and the glomerular filtration of the kidneys were determined radioimmunologically in thyroid function disorders using the endogenous creatinine clearance and the 51Cr-EDTA clearance. Compared to a euthyroid control group 17 patients with hyperthyroidism showed a decreased and 5 patients with hypothyroidism showed a largely toxic digoxin level, both groups being on a maintenance therapy of 0.25 mg digoxin b. i. d. During an oral maintenance therapy of daily 0.1 mg digitoxin unchanged therapeutic serum levels were found in 35 hyperthyroid and 18 hypothyroid patients when compared to a euthyroid control group. Assessment of clearances showed that glomerular filtration rates were clearly increased in the hyperthyroid and lowered in the hypothyroid patients. Renewed assessment of the clearance in four hyperthyroid patients and three with hypothyroidism after thyroid recompensation showed a marked decrease of clearance values in hyperthyroidism and an increase in hypothyroidism. Increased clearance values in hyperthyroidism were associated with lowered digoxin serum levels. In contrast, lowered clearance values in hypothyroidism were accompanied by increased serum digoxin levels. There was no such association detectable for digitoxin.

Topics: Adult; Aged; Creatinine; Digitoxin; Digoxin; Glomerular Filtration Rate; Humans; Hyperthyroidism; Hypothyroidism; Middle Aged

Topics: Animals; Digoxin; Dogs; Female; Hyperthyroidism; Hypothyroidism; Kidney; Kinetics; Radioimmunoassay

The response to a single oral dose of 0.5 mg digoxin has been studied in eight patients, of whom four were hyperthyroid and four were hypothyroid, both before and after treatment for their thyroid dysfunction. The post-dose plasma digoxin levels were significantly lower in the hyperthyroid patients when they were thyrotoxic than when they became euthyroid. In only one hypothyroid patient was the post-dose plasma digoxin level significantly higher before treatment than it was after and in the others the digoxin values reached were either the same as, or lower than, before treatment. There was a significant correlation between the creatinine clearance and the urinary concentrations of digoxin and these both altered with change in thyroid status. Total urinary digoxin excretion did not change. Pharmacokinetic analysis suggested that digoxin was distributed in a way compatible with a two-compartment model and that the volume of the central compartment was high in thyrotoxic patients and low in hypothyroid patients. In both cases it reverted to a median value after treatment. It is recommended that plasma digoxin levels should be monitored in all patients with thyroid dysfunction who require therapeutic digoxin.

Topics: Aged; Digoxin; Female; Humans; Hyperthyroidism; Hypothyroidism; Iodine Radioisotopes; Middle Aged; Models, Biological

Topics: Administration, Oral; Adult; Aged; Creatinine; Digoxin; Female; Glomerular Filtration Rate; Humans; Hyperthyroidism; Hypothyroidism; Injections, Intravenous; Kinetics; Male; Metabolic Clearance Rate; Middle Aged; Models, Biological; Thyroid Diseases

Topics: Digoxin; Humans; Hypothyroidism; Male; Middle Aged

The radioimmunoassay of digoxin is one of the most important services of the nuclear medicine laboratory. Precision and accuracy in the performance of the test are especially critical. A number of commerical kits are available and reliable. Pitfalls to be avoided includelimited availability or delay in performance of the assay; failure to consider senitizing factors; drawing the blood sample too soon after a digoxin dose; failure to consider desensitizing factors; forgetting that renal function is a major determinant of blood and tissue digoxin levels; assuming patient compliance and uniform intestinal absorption (bioavailiability with all digoxin preparations in all patients; attempting to interpret digoxin levels without the necessary clinical information; and failure to deliver the result to the proper person. If one avoids these pitfalls, and important service will be rendered in the evaluation of the patient requiring digitalis therapy.

Topics: Administration, Oral; Aged; Biopharmaceutics; Calcium; Digoxin; Drug Interactions; Female; Heart Diseases; Humans; Hypothyroidism; Hypoxia; Kidney Failure, Chronic; Magnesium; Male; Middle Aged; Potassium; Procainamide; Propranolol; Quinidine; Radioimmunoassay

Topics: Administration, Oral; Adult; Age Factors; Aged; Arrhythmias, Cardiac; Coronary Disease; Digoxin; Electrocardiography; Female; Humans; Hypothyroidism; Male; Middle Aged; Nausea; Potassium; Radioimmunoassay; Rheumatic Heart Disease; Urea; Vomiting

Topics: Adult; Aged; Basal Metabolism; Blood Urea Nitrogen; Digoxin; Female; Humans; Hyperthyroidism; Hypothyroidism; Male; Middle Aged; Thyroid Function Tests; Tritium