Digoxin arrhythmia with

DIGOXIN CALCIUM Risk of cardiac arrhythmias with large intravenous doses of calcium Uncertain it is known that calcium levels directly correlate with the action of digoxin therefore, high levels, even if transient, may t the chance of toxicity It is recommended that parenteral administration of calcium should be avoided in patients taking digoxin. If this is not possible, administer calcium slowly and in small aliquots... 

Supraventricular tachycardia is the major arrhythmia indication for verapamil. Adenosine or verapamil are preferred over older treatments (propranolol, digoxin, edrophonium, vasoconstrictor agents, and cardioversion) for termination. Verapamil can also reduce the ventricular rate in atrial fibrillation and flutter. It only rarely converts atrial flutter and fibrillation to sinus rhythm. Verapamil is occasionally useful in ventricular arrhythmias. However, intravenous verapamil in a patient with sustained ventricular tachycardia can cause hemodynamic collapse. 

Digoxin (see p. 158) shortens the refractory period in atrial and ventricular myocardial cells while prolonging the effective refractory period and diminishing conduction velocity in Purkinje fibers. Digoxin is used to control the ventricular response rate in atrial fibrillation and flutter. At toxic concentrations, digoxin causes ectopic ventricular beats that may result in ventricular tachycardia and fibrillation. [Note This arrhythmia is usually treated with lidocaine or phenytoin.]... 

Medications such as P-blockers, calcium channel blockers, digoxin, and amiodarone can be used to control cardiac conduction abnormalities (arrhythmias), and a pacemaker may be inserted to combat heart failure. The general supportive care measures used in acute stroke syndromes also should be followed. Death in patients with MELAS is usually the result of cardiac failure, pulmonary embolus, or renal failure. 

Digoxin at high levels can cause confusion and sedation in the elderly but Mrs GG does not present with confusion. Also digoxin toxicity can cause arrhythmias or bradycardia which can result in a drop in cardiac output leading to a fall. Again she does not presently exhibit any symptoms of digoxin toxicity so this is unlikely. A digoxin serum level may be useful to confirm this. 

DIGOXIN PARASYMPATHOMIMETICS Cases reports of AV block and bradycardia when edrophonium was co-administered with digoxin Uncertain at present Avoid edrophonium in patients with atrial arrhythmias who are also taking digoxin... 

Acute digoxin poisoning causes initial nausea and vomiting and hyperkalaemia because inhibition of the Na, K" -ATPase pump prevents intracellular accumulation of potassium. The ECG changes (see Table 24.1) of prolonged use of digoxin may be absent. There may be exaggerated sinus arrhythmia, bradycardia and ectopic rhythms with or without heart block. 

Digoxin and Diuretics. One of the problems associated with the use of most of the commonly employed diuretics [e.g., the thiazides furosemide (e.g.,Lasix)], is excessive loss of potassium. Particular caution is necessary in patients also being treated with digoxin, many of whom are also candidates for diuretic therapy. If potassium depletion remains uncorrected, the heart may become more sensitive to the effects of digoxin and arrhythmia may result. 

Because of digoxin s narrow therapeutic range, toxicity can often occur, especially in those who have predisposing factors, such as hypokalemia, concurrent therapy with potassium wasting diuretics, age (elderly and pediatrics), small body size, and drug interactions. Common signs of toxicity include Gl complaints (nausea, vomiting, and anorexia), arrhythmias, and CNS effects (i.e., confusion, hallucinations, and visual disturbances). 

JP is a 35-year-old woman who presents with an uncomplicated UTI. She has a history of cardiac arrhythmias for which she takes amiodarone and digoxin. Her allergies include anaphylaxis to sulfa medications. Which of the following medications would be the best choice to treat her UTI ... 

B Because this patient has asthma and is wheezing, calcium channel blockers are the drug class of choice. Unlike beta-blockers and adenosine, they do not cause bronchospasm. Beta-blockers and adenosine should be used cautiously in patients with obstructive lung disease, and use should be avoided in patients with asthma. Digoxin is not contraindicated, but it is not the drug of choice due to its slow onset. Amiodarone is indicated for ventricular arrhythmias, but not PSVT. 

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