What is a common side effect of an antidepressant overdose?

A common side effect of an antidepressant overdose is urinary retention. In particular, tricyclic antidepressants (TCAs) are known to cause anticholinergic effects, which can lead to urinary retention as a result of decreased bladder contractility. This can occur because these medications block the action of acetylcholine, a neurotransmitter involved in bladder function, leading to the inability to urinate effectively.

Understanding the mechanism behind this side effect is essential, as urinary retention can lead to significant complications, including urinary tract infections and bladder distension. The presentation of urinary retention in the context of an overdose would typically be accompanied by other symptoms related to anticholinergic toxicity, such as dry mouth, constipation, and confusion.

In contrast, the other mentioned options have different associations with antidepressant overdoses. Hypertension can occur with certain stimulant medications but is not a primary concern with typical antidepressants. Bradycardia is not commonly associated with antidepressant overdose and would more likely be seen with other drug categories like opioids. Excessive salivation is not typically a side effect; rather, it might indicate other neurological or systemic issues unrelated to the effects of antidepressants.