Do serotonin reuptake inhibitors worsen outcome of patients referred to the emergency department for deliberate multi-drug exposure?

Abstract

Incidence of poisonings with serotonin reuptake inhibitors (SRIs) is growing. SRI toxicity is considered low, but its actual impact in multi-drug poisonings remains unclear. Our objective was to evaluate the consequences of SRI exposure in patients referred to the emergency department (ED) for deliberate multi-drug exposure. Patients admitted for multi-drug exposure involving at least one SRI were matched with patients who did not ingest any SRI, according to age, gender, type of drug and ingested doses. Features of serotonin syndrome according to Sternbach's criteria and Hunter's serotonin toxicity criteria were evaluated from records. In 4 years, 148 SRI-exposed patients were included and compared to 296 matched controls. The SRIs mainly involved were escitalopram (22%), venlafaxine (20%), fluoxetine (19%), citalopram (15%) and paroxetine (11%). Serotonin syndrome was diagnosed in one patient, but actually occurred in five SRI-exposed patients based on the retrospective evaluation of records. Twenty patients (14%) exhibited one or more serotonin syndrome criteria. At least two of 11 of Sternbach's criteria and two of nine of Hunter's serotonin toxicity criteria were missing in each chart. Using a conditional logistic regression analysis, seizures (p = 0.04) and serotonin syndrome (p = 0.01 based on Sternbach's criteria and p = 0.004 based on Hunter's serotonin toxicity criteria) more frequently occurred in SRI-exposed patients. Requirement for mechanical ventilation was significantly increased (p = 0.03), although admission to the intensive care unit was not. In multi-drug-poisoned patients admitted to the ED, exposure to SRIs significantly increases the risk of seizures and requirement for mechanically ventilation. Diagnosis of serotonin syndrome remains insufficient justifying improved training.