Digoxin-Like Immunoreactive Substance in Renal Failure

Saime Paydas, MD, Department of Internal Medicine, Faculty of Medicine, Çukurova University, TR-01330 Adana (Turkey) Table 1. Characteristics of patients and controls Table 2. Correlation of serum digoxin and digitoxin levels with urea, Cr, Ccr, blood pressure, heart failure and edema analysis by RIA (kit: Coat-A-Count Diagnostic Products Corporation, Los Angeles, Calif., USA). Student’s t test and Pearson correlation were used for statistical evaluation. Table 1 shows the characteristics of patients and controls. There was no significant difference in the mean serum digoxin level between the patients and healthy controls, but the mean serum digitoxin values were found Dear Sir, The cardiac glycosides digoxin and digi-toxin are important drugs in the management of heart failure and arrhythmias, and can be measured by radioimmunoassay (RIA) in serum and urine. It is known that cardiac glycosides have a high toxicity and narrow therapeutic ranges (usually 0.8-2.0 ng/ml) [1]. It has recently been reported that detectable levels of digoxin-like immunoreactive substance (DLIS) are found in third trimester pregnant women, neonates, patients with liver disease, patients with acute and chronic renal failure, hemodialysis patients and normal subjects [2-7]. These studies show that monitoring cardiac glycoside concentrations in serum is an important and useful measurement in patients with renal failure. We measured DLIS in the serum of renal failure patients and normal subjects. Patients, Methods and Results Serum samples were obtained from 51 patients (23 males, 28 females) and from 25 healthy controls (13 males, 12 females). None of the patients or controls were receiving any cardiac glycosides. Patients had various ne-phropathies: essential hypertension 38 cases; chronic glomerulonephritis 4 cases; chronic tubulointerstitial nephropathy 5 cases; diabetic nephropathy 3 cases, and amyloidosis 1 case. We assessed hematocrit, white blood cell, sedimentation, blood urea nitrogen, serum creatinine (Cr) and creatinine clearance (Ccr) in patients and healthy controls. We recorded whether patients had heart failure or not. Blood samples were stored at -20 °C until