Introduction: The safety of antidepressants following overdose is critical because of the high risk of suicide attempts in depressed patients. This study was conducted to decrease the fatality rate of antidepressant overdoses by providing data to shift prescribing toward safer antidepressants.

Methods: US poison control data for 2000-2004 were analyzed by 25 antidepressant types. Medical outcome differences were quantified using a hazard index (number of major or fatal outcomes per 1000 reported antidepressant ingestions).

Results: Of 82,802 suicidal single-agent ingestions of identifiable antidepressants approved for use in the US, cases occurred predominantly in females and peaked in teens. Fatal cases peaked at 40 to 49 years of age. Suicidal ingestions of the SSRIs, SNRIs, and other antidepressants peaked in teens, lithium in the twenties, tricyclics and tetracyclics in the thirties, and MAO inhibitors in the forties. There were 40 major or fatal outcomes per 1000 cases. Weighted by antidepressant type, the mean hazard index for the 25 antidepressants was 79 (range: 0 to 292). Amoxapine (292), maprotiline (211), and desipramine (187) had the highest hazard indices. The tricyclic antidepressants, MAO inhibitors, maprotiline, and bupropion were in the more severe half of antidepressants, ranked by hazard index. All SSRIs had low hazard indices. Hazard index and exposure frequency were inversely correlated (R = -0.423, p = 0.035), while hazard index and use of critical care were positively correlated for the 25 antidepressant types (R = 0.797, p < 0.001). Clinical effect profiles for each antidepressant type are presented.

Conclusion: Suicidal overdose severity varied considerably by antidepressant type. Prescribing decisions should be informed by regularly updated comparative overdose severity data.