Digoxin and digitoxin elimination in man by charcoal hemoperfusion

Summary Since there is no widely used causal means of reducing the severity of massive digitalis intoxication the capability of hemoperfusion with coated activated charcoal to remove toxicologically relevant amounts of digoxin and digitoxin was evaluated in vitro and in man. At a blood flow rate of 100 ml/min the digoxin clearance by hemoperfusion in vitro was 51±8 ml/min in comparison to 24.3±11.3 ml/min by hemodialysis. The average hemoperfusion clearance of digitoxin was 31.7±13.4 ml/min, whereas almost no digitoxin was removed by hemodialysis. These clearance values point to the ability of hemoperfusion of eliminating digitalis glycosides from the blood. They do not clarify the essential question whether it is possible to lower the toxic concentrations in the tissues.In two patients being on hemoperfusion for other reasons, 0.5 mg digoxin were injected intravenously as a bolus 1 h prior to the beginning of hemoperfusion and 0.125 mg/h were infused continuously over 4h simultaneously with hemoperfusion. By an average digoxin clearance of 77 ml/min, only 5 and 4.5% of the dose given were removed by this procedure. In 2 patients receiving digitoxin under the same trial conditions an average of 24% of the digitoxin load were eliminated by 4 to 6 h hemoperfusion period although the clearance values obtained were below the clearance for digoxin.The lack of effectiveness in eliminating toxicological relevant amounts of digoxin is due to the quite high distribution volume which results in high tissue concentrations and low blood concentrations of the drug. On the other hand the effective removal of digitoxin is due to the appreciably smaller distribution volume and suggests that hemoperfusion may be a valuable method of rapid reversal of advanced digitoxin toxicity in man.Supported by a grant of Deutsche Forschungsgemeinschaft