Plasma-digoxin and serum creatinine concentrations were determined on admission in 145 unselected patients previously digitalized as outpatients. Adequate digitalization was found in 62.7%, inadequate doses in 15.9% of patients. In the latter group the daily dosage reported by the patients failed to correlate with the plasma-digoxin concentration by radioimmunoassay. One-fifth of all patients had clinical evidence of digitalis intoxication. Of these, 69% had plasma-digoxin concentrations of more than 2.0 ng/ml and 31% less than 2.0 ng/ml. Mean digoxin concentration for all patients with signs of digitalis intoxication was 2.5+/-0.9 ng/ml. In patients simultaneously receiving spironolactone or canrenoate-K+ there was danger of falsely high values for digoxin because of interference of those drugs with the radioimmunoassay.
Ambulatory Care Canrenoic Acid