oleandrin and Poisoning

Cardiac glycosides of plant origin are implicated in toxic ingestions that may result in hospitalization and are potentially lethal. The utility of commonly available digoxin serum assays for detecting foxglove and oleander ingestion has been demonstrated, but no studies have evaluated the structurally similar convallatoxin found in Convallaria majalis (lily of the valley) for rapid laboratory screening, nor has digoxin immune Fab been tested as an antidote for this ingestion.. We aimed to (1) evaluate multiple digoxin assays for cross-reactivity to convallatoxin, (2) identify whether convallatoxin could be detected in vivo at clinically significant doses, and (3) determine whether digoxin immune Fab could be an effective antidote to convallatoxin.. Cross-reactivities of purified convallatoxin and oleandrin with five common digoxin immunoassays were determined. Serum from mice challenged with convallatoxin was tested for apparent digoxin levels. Binding of convallatoxin to digoxin immune Fab was determined in vitro.. Both convallatoxin and oleandrin were detectable by a panel of commonly used digoxin immunoassays, but cross-reactivity was variable between individual assays. We observed measurable apparent digoxin levels in serum of convallatoxin intoxicated mice at sublethal doses. Convallatoxin demonstrated no binding by digoxin immune Fab.. Multiple digoxin immunoassays detect botanical cardiac glycosides including convallatoxin and thus may be useful for rapid determination of severe exposures, but neutralization of convallatoxin by digoxin immune Fab is unlikely to provide therapeutic benefit.

Topics: Animals; Animals, Outbred Strains; Cardenolides; Cardiotonic Agents; Convallaria; Cross Reactions; Digoxin; Dose-Response Relationship, Drug; Female; Immunoassay; Immunoglobulin Fab Fragments; Lethal Dose 50; Mice; Plant Poisoning; Poisoning; Strophanthins; Vasodilator Agents

The study presents a case of non-fatal poisoning with oleander blooms in a 47-year-old female, with emphasis on the importance of toxicological service in a clinical emergency. After repeated vomiting at home, the patient was admitted at the hospital with cardiac symptoms more than 18 h after the ingestion. Serum samples were assayed immunochemically for digitoxin-related compounds by electrochemiluminescent immunoassay, and using HPLC/MS/MS analysis for oleandrin, the main cardiac glycoside of Nerium oleander. Confirming the non-specific immunoassay results, which are often clinically over-interpreted, oleandrin was detected by HPLC/MS/MS in the serum sample in a concentration of 1.6 ng/ml upon admission. Comparison with previous reports indicates that single compound analysis only permits a toxicological assessment for oleander poisoning and results in the proposal to classify an oleandrin level between 1.0 and 2.0 ng/ml as toxic blood plasma/serum concentration.

Topics: Cardenolides; Chromatography, High Pressure Liquid; Female; Humans; Immunoassay; Luminescent Measurements; Mass Spectrometry; Middle Aged; Nerium; Poisoning; Sensitivity and Specificity