A patient with major depressive disorder is started on an SNRI. The mechanism by which SNRIs are effective involves:

• A Inhibition of serotonin and norepinephrine reuptake transporters (SERT and NET) ✓
• B Antagonism at 5-HT2A and dopamine D2 receptors
• C Irreversible inhibition of monoamine oxidase A and B
• D Blockade of presynaptic alpha-2 heteroreceptors and autoreceptors

Explanation

SNRIs (serotonin-norepinephrine reuptake inhibitors) such as venlafaxine, duloxetine, and desvenlafaxine inhibit both SERT and NET, increasing synaptic concentrations of both serotonin and norepinephrine. The norepinephrine component is thought to contribute to analgesic effects (useful in neuropathic pain) and to address energy and motivation deficits. Mirtazapine (option D) enhances both monoamines via presynaptic alpha-2 blockade. MAO inhibitors work by option C. Atypical antipsychotics work by option B.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.