Name a common SNRI and identify a key pharmacologic difference from SSRIs.

Name a common SNRI and identify a key pharmacologic difference from SSRIs.

• A. Fluoxetine; SNRI increases serotonin only.
• B. Venlafaxine; SNRIs increase both serotonin and norepinephrine.
• C. Duloxetine; SNRIs decrease dopamine.
• D. Sertraline; SNRIs primarily affect GABA.

Answer: (B)

SNRIs differ from SSRIs by blocking the reuptake of two monoamines rather than one. A common SNRI is venlafaxine. The key difference is that SSRIs selectively inhibit serotonin reuptake, increasing only serotonin in the synapse. SNRIs, on the other hand, inhibit reuptake of both serotonin and norepinephrine, boosting their levels in the brain. Venlafaxine exemplifies this through a dose-dependent pattern: at lower doses it mainly increases serotonin, but at higher doses it also substantially enhances norepinephrine reuptake inhibition, giving it the dual monoaminergic effect characteristic of SNRIs.

SNRIs differ from SSRIs by blocking the reuptake of two monoamines rather than one. A common SNRI is venlafaxine. The key difference is that SSRIs selectively inhibit serotonin reuptake, increasing only serotonin in the synapse. SNRIs, on the other hand, inhibit reuptake of both serotonin and norepinephrine, boosting their levels in the brain. Venlafaxine exemplifies this through a dose-dependent pattern: at lower doses it mainly increases serotonin, but at higher doses it also substantially enhances norepinephrine reuptake inhibition, giving it the dual monoaminergic effect characteristic of SNRIs.