SSRI Safety in Overdose

Background: The morbidity and mortality caused by tricyclic antidepressant (TCA) overdose arewell recognized. Among newer antidepressants, the selective serotonin reuptake inhibitors (SSRIs)are thought to be safer in overdose. This study was designed to describe the signs, symptoms, andmortality associated with SSRI overdose. Method: English-language articles identified throughMEDLINE (1985 through 1997), and case reports from the American Association of Poison ControlCenters (AAPCC) (1987 through 1996) and United States Food and Drug Administration (FDA) adverseevent database (through 1997) that describe findings of fatal and nonfatal overdoses involvingSSRIs alone or in combination with other ingestants were reviewed. Results: SSRI antidepressantsare rarely fatal in overdose when taken alone. During the 10 years that SSRI antidepressants havebeen marketed, there have been remarkably few fatal overdoses reported in the literature or to theAAPCC or FDA involving ingestion only of an SSRI. Moderate overdoses (up to 30 times the commondaily dose) are associated with minor or no symptoms, while ingestions of greater amounts typicallyresult in drowsiness, tremor, nausea, and vomiting. At very high doses (> 75 times the commondaily dose), more serious adverse events, including seizures, electrocardiogram (ECG) changes, anddecreased consciousness may occur. SSRI overdoses in combination with alcohol or other drugs areassociated with increased toxicity, and almost all fatalities involving SSRIs have involved coingestionof other substances. Conclusion: The SSRI antidepressants are far safer than the TCAs in overdose.There is no apparent difference among SSRIs with respect to overdose safety.