RELATIONSHIP BETWEEN HIGH SERUM DIGOXIN LEVELS AND TOXICITY

A retrospective study of 1,269 patients on digoxin was done to determi ne the relationship between serum digoxin levels of 3.0 ng/ml or highe r and clinical toxicity. Of 1,269 patients, 58 (4.6%) had digoxin seru m levels of 3.0 ng/ml or higher. Clinical evidence of digoxin toxicity was present in only 11 of these patients and premature blood sampling accounted for the high levels in 10 other nontoxic patients. None of the patients with clinical toxicity died. The other 37 patients tolera ted the high digoxin levels without exhibiting toxic effect. Low cardi ac output, concomitant use of other drugs, and impaired renal function increased the serum digoxin levels in patients with and without clini cal toxicity. Appropriate therapeutic digoxin level monitoring and con firmatory laboratory-clinical relationship may have important influenc es on these results. Additional work on further definition of ''toxic' ' digoxin levels needs to be performed.