A patient with congestive heart failure was started on digoxin and diuretics. He later presents with bradycardia and GIT upset and visual disturbances. His K+ was found to be 2.5 The reason for these feature is
(B) Digoxin toxicity > Digitalis is effective in patients with systolic HF complicated by atrial flutter and fibrillation and a rapid ventricular rate, who benefit both from slowing of the ventricular rate and from the positive inotropic effect.> Although digitalis does not improve survival in patients with systolic HF and sinus rhythm, it reduces symptoms of HF and the need for hospitalization.> Digitalis is of little or no value in patients with HF, sinus rhythm, and the following conditions: hypertrophic cardiomyopathy, myocarditis, mitral stenosis, chronic constrictive pericarditis, and any form of diastolic HF.> Digoxin, which has a half-life of 1.6 days, is filtered n the glomeruli and secreted by the renal tubules. Significant reductions of the glomerular filtration rate reduce the elimination of digoxin and, therefore, may prolong digoxin's effect, allowing it to accumulate to toxic levels, unless the dose is reduced.> DIGITALIS INTOXICATION: This is a serious and potentially fatal complication. Advanced age, hypokalemia, hypomagnesemia, hypoxemia, renal insufficiency, hypercalcemia, and acute myocardial infarction all may reduce tolerance to digitalis. Chronic digitalis intoxication may be insidious in onset and is characterized by anorexia, nausea, and vomiting, exacerbations of HF, weight loss, cachexia, neuralgias, gynecomastia, yellow vision, and delirium. The most frequent disturbances of cardiac rhythm are ventricular premature beats, bigeminy, ventricular tachycardia, and, rarely, ventricular fibrillation. Atrioventricular block and nonparoxysmal atrial tachycardia with variable atrioventricular block are characteristic of digitalis intoxication; withdrawal of the drug and treatment with li-adrenocepior blocker or lidocaine are indicated. If hypokalemia is present, potassium should be administered cautiously by the oral route. Fab fragments of purified, intact digitalis antibodies are a potentially lifesaving approach to the treatment of severe intoxication.> The administration of quinidine, verapamil, amiodarone, and propafenone to patients receiving digoxin raises the serum concentration of the latter, increasing the propensity to digitalis intoxication.> The dose of digitalis should be reduced by half in patients receiving these drugs.
Left ventricular aneurysm
Digoxin toxicity
Viral gastroenteritis
Hypokalemia
Miscellaneous