Which antidepressant class is known for being lethal in overdose?

Tricyclic antidepressants (TCAs) are particularly known for their potential lethality in overdose situations. This is largely due to their pharmacological properties, which include anticholinergic effects and the ability to inhibit cardiac conduction. When taken in high doses, TCAs can lead to serious cardiac arrhythmias and other critical symptoms that can complicate treatment and increase the risk of death.

In contrast, selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) tend to have a much wider therapeutic index, which makes them less dangerous in an overdose scenario. Monamine oxidase inhibitors (MAOIs), while they can also have serious interactions and side effects, typically don't have the same acute cardiotoxic risks associated with overdose as TCAs do. This makes TCAs uniquely hazardous in terms of overdose potential, which is why they are recognized for their lethality when misused.