Torsade de pointes tachycardias induced by overdosage of zimeldine.
Torsade de pointes tachycardias may occur in connection with overdoses, and more rarely with therapeutic doses, of tricyclic antidepressant agents and antiarrhythmic drugs, especially in the presence of hypokalemia. Zimeldine is a selective serotonin reuptake blocker, which according to studies in humans and animals, has no serious cardiovascular side effects in therapeutic doses. We report a patient who was admitted with repeated syncopal attacks resulting from prolonged QT intervals and torsade de pointes tachycardias. She also had hypokalemia, although she had had no treatment known to affect the potassium level. Correction of the potassium level rapidly prevented further tachycardias and led to normalization of the QT interval. Repeated blood samples verified high levels of zimeldine and its metabolites. We conclude that whenever torsade de pointes tachycardias occur, treatment with antidepressant or antiarrhythmic agents should be immediately suspected and verified. In addition, prompt initiation of potassium infusion may dramatically resolve the arrhythmias, even if the serum potassium level is within the lower normal range, and may also potentiate the effect of class I antiarrhythmic drugs such as lidocaine.
Liljeqvist
J A
JA
Medical Department I, Sahlgren's Hospital, Göteborg, Sweden.
Edvardsson
N
N
D000368:Aged; D004562:Electrocardiography; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D013610:Tachycardia / Q000139:chemically induced* / Q000503:physiopathology; D015031:Zimeldine / Q000506:poisoning*
D015031:Zimeldine