Serotonin and norepinephrine reuptake inhibitor (SNRI)

SNRIs function by inhibiting the reuptake of both serotonin and norepinephrine neurotransmitters in the brain. They block the transporters responsible for removing these neurotransmitters from the synaptic cleft, thereby increasing their concentration and prolonging their effects[1][2]. This dual action distinguishes SNRIs from SSRIs (selective serotonin reuptake inhibitors), which primarily affect serotonin. Different SNRIs have varying selectivity ratios for serotonin versus norepinephrine reuptake inhibition; for example, venlafaxine has a 30:1 ratio favoring serotonin, while levomilnacipran has greater potency for norepinephrine reuptake inhibition[3][4]. SNRIs work alongside their metabolites to achieve their therapeutic effects and may also indirectly increase dopamine neurotransmission in certain brain regions[3]. They are FDA-approved for treating depression and are also used for anxiety disorders and chronic pain conditions, particularly neuropathic pain[1][2]. The norepinephrine component is considered especially important for pain management, as medications that only affect serotonin (SSRIs) have not proven effective for pain disorders[4].

Other names

Serotonin-norepinephrine reuptake inhibitorSerotonin-noradrenaline reuptake inhibitorDual reuptake inhibitorDual-action antidepressant

Inhibition of presynaptic neuronal uptake of serotonin and norepinephrine[2] - Prolongation of monoamine effects in the synaptic cleft[2] - Increased postsynaptic receptor activation[2] - Enhanced neuronal activities[2] - Dose-dependent and agent-dependent reuptake inhibition[2][4] - Anti-inflammatory action on microglia[3]