Découverte fortuite d'une intoxication aiguë par vérapamil forme à libération prolongée : intérêt du criblage toxicologique.

Objectives:A29-year oldmanwasadmitted in intensive care unit for resistant hypotensionandcardiacrhythm disturbances. Since a bisoprolol overdose was suspected, a toxicological screening was carried out on serum. This screening didn't show bisoprolol but revealed verapamil intoxication. To confirm the diagnosis, verapamil and its main metabolites were assayed on 6 serum samples taken over the period of hospitalization. Methods: Verapamil and metabolites were identified by LC-MS/MS. Metabolites have been previously recognized after mouse liver microsomal incubation and added to the data library. Results: Seven verapamil metabolites were identified after mouse liver microsomal incubation. Five of them were found in serum samples. Kinetics of verapamil and its main metabolites (norverapamil and N-desalkylverapamil) in serum samples revealed 3 stages: increase during the 1st day, stability during 3 days and decrease on 5th and 6th days. Conclusion: The present case demonstrates the importance of toxicological screening in the diagnosis of drugs overdose. The stagnation of serum levels during 3 days could be explained by intoxication with a sustained-release formulation of verapamil. [ABSTRACT FROM AUTHOR]