To the Editor.
—Regarding the article by Lai et al on "Hemofiltration in Digoxin Overdose" that appeared in the June issue of the Archives,1 I should like to point out that only about 15% to 20% (0.15 to 0.25) of digoxin is protein bound, contrary to the figure quoted by the authors.2 This should make possible the hemoperfusion of even more digoxin. I adopt the view that despite the modest fall in serum digoxin level, the amount of digoxin removed from the body was minute compared with total body stores of the drug. The major reservoir for the drug is skeletal muscle. Cardiac muscle contains about 30 times the amount present in serum.3,4 One hundred fifty billionths of a gram per minute removed for two days would result in a total removal of 720 000 ng of digoxin—a very small amount. Clinical improvement in this patient probably