What side effect is commonly associated with the use of tricyclic antidepressants?

The commonly associated side effect with tricyclic antidepressants (TCAs) is their potential for fatal overdose. TCAs, due to their mechanism of action as norepinephrine and serotonin reuptake inhibitors, can lead to significant toxicity, particularly when taken in overdose situations. The narrow therapeutic index of these medications means that the difference between a therapeutic dose and a toxic dose is small. This makes the risk of overdose a serious concern, often resulting in life-threatening conditions such as cardiac arrhythmias and central nervous system depression.

In contrast, while nausea and sleep disturbances can also occur with TCAs, they are not as prominent or severe as the danger posed by overdose. Severe respiratory depression is not typical for TCAs, as this is more commonly associated with other classes of medications, such as opioids or benzodiazepines. Thus, the unique and serious nature of the overdose potential clearly establishes it as a key concern in the use of tricyclic antidepressants.