Serum Levels of Digoxin in Thai Patients: A Preliminary Report

Abstract

Seven patients with congestive heart failure admitted to Maharaj Nakorn Chiang Mai Hospital were used in this study. Every patient was treated with various doses of digoxin. Their serum levels of digoxin were measured by the method of fluorescence polarization immunoassay (FPIA). Serum levels of digoxin in five patients correlated well with clinical responses while the other two did not. Two patients with serum levels below 0.9 ng/ml correlated with poor responses to digoxin treatment while serum levels of 1.39 and 1.58 ng/ml in two patients agreed with good clinical findings. Among three patients diagnosed to be digoxin intoxication. Only one exhibited serum level (3.3 ng/ml) of toxic range, serum levels of the other two patients were too low to be toxic. These latter two patients were elderly, thin with underlied chronic obstructive pulmonary disease. The results of this preliminary study suggest that FPIA may be a potentially useful tool for quantitating serum levels of digoxin.