β2-Microglobulin adsorption column reduces digoxin trough level during hemodialysis: Three case reports

We have previously reported that a β 2 -microglobulin adsorption column for the treatment of dialysis-related amyloidosis decreased serum digoxin concentration in renal failure patients. Because the distribution volume of digoxin is high, it is uncertain whether the repetitive use of this column influences the pharmacokinetics of digoxin in renal failure patients. We have observed 3 renal failure patients whose trough serum digoxin concentrations were significantly reduced by the repetitive use of tandem β 2 -microglobulin adsorption columns for treatment of dialysis-related amyloidosis. These patients experienced symptomatic elevation oftheir heart rates in parallel with a significant reduction in serum digoxin concentrations. Termination of the use of the adsorption column improved the symptoms in I patient; however, severe arthritic pain caused by amyloidosis relapsed. Dosage of digoxin was increased in 2 other patients with continuous treatment by the column. Their digoxin concentrations increased, and their heart rates decreased without any deterioration of joint pain. We have demonstrated that the repetitive use of the β 2 -microglobulin adsorption column in tandem with standard hemodialysis actually decreases trough digoxin concentration in renal failure patients. Careful monitoring and alteration of digoxin dosage regimens are needed under these circumstances.