Prolonged QTc interval due to escitalopram overdose

Drugs most commonly responsible for the acquired form of long QT syndrome are antibiotics and antidepressants. Escitalopram overdose leading to prolongation of the QTc interval has only twice been previously described in the literature.

We report a 33-year-old Caucasian woman who attempted suicide by ingesting 15-20 pills of lithium (300 mg each), 15-20 pills of escitalopram (20 mg each), and alcohol. An electrocardiogram (ECG) on admission to the medicine telemetry unit showed a QTc prolongation of 491 ms and normal sinus rhythm. Repeat ECG 18 hours after admission showed a QTc of 502 ms and sinus bradycardia. Serial ECGs were continued with the following results of QTc/hours after admission: 499 ms/2, 485 ms/25 (> 1 day), 469 ms/41, 461 ms/71, 476 ms/97 (> 4 days). After the QTc interval had declined to 461 ms after more than 2 days (71 hours), the patient was transferred to the inpatient psychiatry ward service.

Prescribers may wish to exercise caution when administering escitalopram to patients who have suicidal ideations and depression. In the event of an overdose, QT prolongation can occur and ECG monitoring should take place for at least 2 days after ingestion in order to prevent life-threatening arrhythmias such as torsades de pointes (tdp). Other factors and drugs that could contribute to prolongation of the QT interval should be taken into account when determining the time period needed for ECG monitoring in the individual patient.