Which medication is NOT an SNRI?

• A. Venlafaxine (Effexor)
• B. Desvenlafaxine (Pristiq)
• C. Escitalopram (Lexapro)
• D. Duloxetine (Cymbalta)

Answer: (C)

The correct identification of escitalopram (Lexapro) as not being a serotonin-norepinephrine reuptake inhibitor (SNRI) is based on its pharmacological classification. Escitalopram is classified as a selective serotonin reuptake inhibitor (SSRI). SSRIs primarily focus on increasing levels of serotonin in the brain by inhibiting its reuptake into the presynaptic cell. This mechanism differs from that of SNRIs, which target both serotonin and norepinephrine neurotransmitters.

In contrast, the other medications listed, such as venlafaxine, desvenlafaxine, and duloxetine, are all recognized as SNRIs. They enhance the levels of both serotonin and norepinephrine by blocking their reabsorption into the nerve cells, which can lead to a different therapeutic profile and efficacy for conditions such as depression and anxiety. Thus, recognizing escitalopram’s distinct mechanism and classification is crucial to understanding its role compared to SNRIs.