Interpretation of excessive serum concentrations of digoxin in children.
Between January 1981 and April 1984, excessive serum concentrations of digoxin (5 ng/ml or higher) were recorded in 47 children, aged 2 days to 16 years. In 10 patients, the high concentrations were measured 9.25 to 48 hours after death and were significantly higher than antemortem levels in all cases (8.3 +/- 2.4 (+/- standard deviation) postmortem vs 3.3 +/- 1.5 antemortem, less than 0.0001). In 15 patients (40.5% of the living patients) serum concentrations of 5 ng/ml or higher reflected sampling errors; drug levels were monitored too closely to the administration of a dose. None of these children had toxic manifestations of digoxin. In 10 patients, the excessive concentrations were associated with renal failure and a prolonged elimination half-life (T1/2) of digoxin; in 3 of these patients, there were signs of digoxin toxicity. Six cases were caused by digoxin overdose (accidental ingestions, pharmacy error and a suicide attempt). In 6 additional cases, the existence of an endogenous digoxin-like substance (EDLS) was shown to contribute to the excessive levels of the drug. One case could be attributed to digoxin-amiodarone interaction. In 10 of 37 living patients, digoxin toxicity was diagnosed. After excluding the 15 sampling errors and 6 cases with EDLS, this represents 63% of the cases. There was a good correlation between digoxin elimination T1/2 and serum creatine concentrations (r = 0.71, p less than 0.01). The above observations suggest that excessive serum concentrations of digoxin may not necessarily reflect potentially toxic levels.(ABSTRACT TRUNCATED AT 250 WORDS)
D000293:Adolescent; D000638:Amiodarone / Q000097:blood; D001798:Blood Proteins; D002298:Cardenolides; D004077:Digoxin / Q000009:adverse effects* / Q000097:blood / Q000506:poisoning; D004347:Drug Interactions; D005260:Female; D006207:Half-Life; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007676:Kidney Failure, Chronic / Q000378:metabolism; D008297:Male; D012503:Saponins
D001798:Blood Proteins; D002298:Cardenolides; D012503:Saponins; C034504:digoxin-like factors; D004077:Digoxin; D000638:Amiodarone