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Sodium Channel Blockade With QRS Widening After an Escitalopram Overdose

Schreffler, Susan M. MD; Marraffa, Jeanna M. PharmD; Stork, Christine M. PharmD; Mackey, Jennifer MD

doi: 10.1097/PEC.0b013e3182a314b7
Illustrative Cases

Introduction: Escitalopram is rarely associated with prolongation of the QTc interval; however, there are no reported cases of QRS complex widening associated with escitalopram overdose. We report a case of a patient who presented with both QRS complex widening and QTc interval prolongation after an escitalopram overdose.

Case: A 16-year-old girl presented to the emergency department after ingestion of escitalopram, tramadol/acetaminophen, and hydrocodone/acetaminophen. Laboratory results were significant for 4-hour acetaminophen 21.1 μg/mL. Serum electrolytes including potassium, magnesium, and calcium were all normal. Initial electrocardiogram (ECG) revealed a widened QRS with an incomplete right bundle branch pattern. After administration of 100-mEq sodium bicarbonate, a repeat ECG revealed narrowing of the QRS complex and a prolonged QTc interval. Magnesium sulfate 2 g intravenous and sodium bicarbonate drip were initiated. A repeat ECG, 1 hour after the second, revealed normalization of the QRS complex and QTc interval.

Discussion: Prolongation of the QTc interval is an expected effect of escitalopram. Both escitalopram and citalopram are metabolized to the cardiotoxic metabolite S-didesmethylcitalopram and didesmethylcitalopram, respectively, which have been implicated in numerous cardiac abnormalities including widening of the QRS complex. Although never previously described with escitalopram, this mechanism provides a reasonable explanation for the QRS complex widening and incomplete right bundle branch block that occurred in our patient.

Conclusions: Both QRS complex widening and QTc interval prolongation should be monitored in cases of escitalopram and citalopram overdoses.

From the Department of Emergency Medicine, Upstate Medical University, Syracuse NY.

Disclosure: The authors declare no conflict of interest.

Reprints: Susan M. Schreffler, MD, 550 E. Genesee St, Syracuse, NY 13202 (e-mail: schreffs@upstate.edu).

© 2013 Lippincott Williams & Wilkins, Inc.