Symptoms of digitalis toxicity include anorexia, nausea, headache, blurring or yellowing of vision, and disorientation. Cardiac toxicity may take the form of atrioventricular conduction or sinus node depression; junctional, atrial, or ventricular premature beats or tachycardias; or ventricular fibrillation. Serum potassium level should be maintained in the high normal range. 

Lidocaine or phenytoin may be useful for ventricular arrhythmias, as is overdrive pacing. But quinidine, amiodarone, and propafenone should be avoided because they will increase digoxin levels.  

Electrical cardioversion should be avoided if possible, since it may cause intractable ventricular fibrillation or cardiac standstill. Pacing is indicated for complete heart block and symptomatic or severe AV block (heart rate <40/min) if they persist after treatment with atropine.  

Digoxin immune fab are available for life-threatening toxicity or large overdoses, but it should be remembered that their half-life is shorter than that of digoxin and so repeat administration may be required.