The Influence of Hemodialysis on Concentration of Serum Digoxin-Like Substance

Abstract

INTRODUCTION:

The radioimmunoassay for measuring serum digoxin concentration have given clinicians a chance to study the pharmacokinetics of digoxin, its interactions with other drugs, the determina tion of the therapeutic range, and the document ation of high concentrations in the serum of patients with clinical signs of digoxin toxicity.In this work, we were interested in finding out whether hemodialysis has an influence on the false positive concentrations of digoxin in the serum of uremic patients. This fact has been reported in literature in a very small group of patients (9,10).

PATIENTS AND METHODS:
The investigation included all patients with acute and chronic renal failure who were treated with extracorporeal hemodialysis in our Hemo dialysis Centre during January and February 1984, and who had never received digoxin, or who had not received digoxin during at least the last year. Samples of 2 ml of blood were taken from all patients in supine position before and after hemodialysis.

Statistical analysis of the obtained results was expressed as the difference of the arythmetic means of the small dependent samples (11).

RESULTS:

In the control group of  five healthy subjects, concentrations of digoxin were at or hear zero. The age range of the group was 36 to 41 years, with an average of 38 years. In the group of 31 patients with renal failure, there were 10 females and 21 males, (18 to 63 years) with an average age of 43 years. Twenty-eight patients in this group were on the program of chronic maintenance hemodialysis for chronic renal failure, and three male patients had acute renal failure which had to be treated with hemodialysis.Patients who were negative before and after hemodialysis 1.75 kg (0.5 – 2.4 kg). The serum sodium concentration before hemodialysis was 122 – 142 nmol/L (average 136 + 4.2 nmol/L) and potassium between 3.5 -5.2 nmol/L (average 5.2 + 0.8 nmol/L).

DISCUSSION:

Circulatory endogenous plasma substance, which reacts with antibodies against digoxin, has been of scientific interest from the first observationin experiments on dogs (1) and monkeys (2). It was assumed that it could be a natriburetic hormone-like substance.In wide’s stuy (10), a very small number of uremic patients on hemodialysis had digoxin-like immunoreacting activity concentrations before hemodialysis, with 0.091 and 0.079 mg/ml after hemodialysis, suggesting that they can not relate to the theoretical removal of an uremic toxin and or endogenous inhibition of the Na, K pump.