SNRI

SNRI stands for serotonin-norepinephrine reuptake inhibitor. It's a class of antidepressant medications that adjust two brain chemicals at once and is used for depression, anxiety, and some pain conditions.

Definition from Shrinktionary, reviewed by Shariq Refai, MD, MBA, FAPA (last reviewed 2026-06-26). Shrinktionary is the network's language layer and carries the canonical short definition; this page adds the research-context detail below. Full definition on Shrinktionary →

SNRIs act on two brain messengers, serotonin and norepinephrine. Common SNRIs include venlafaxine and duloxetine. Like SSRIs, they're antidepressants that are well studied for anxiety, and they take several weeks to reach a clear effect.

SNRIs are a first-line option for generalized anxiety disorder and are also used for social anxiety disorder and panic disorder. Meta-analyses place their effect size in a similar small-to-moderate range as SSRIs. They're often considered when an SSRI hasn't worked or wasn't tolerated, though either class can be a first choice.

A person whose anxiety didn't improve on an SSRI is switched to an SNRI, which acts on an additional brain messenger.

SNRIs carry the same FDA boxed warning about suicidal thoughts in patients under 25 as other antidepressants. Venlafaxine in particular leaves the body quickly, which makes discontinuation syndrome more likely if it's stopped abruptly. SNRIs can also raise blood pressure at higher doses.