Pristiq Classification
Pristiq (desvenlafaxine) is a serotonin-norepinephrine reuptake inhibitor (SNRI), a class of second-generation antidepressants that inhibit the presynaptic reuptake of both serotonin and norepinephrine. 1
Mechanism and Pharmacology
- Desvenlafaxine is the major active metabolite of venlafaxine, but is marketed as a distinct medication with its own FDA approval 1, 2
- The drug binds to both serotonin and norepinephrine transporters with relatively low potency but balanced activity (approximately 10:1 ratio for serotonin to norepinephrine) 2, 3
- Unlike SSRIs (selective serotonin reuptake inhibitors), SNRIs like desvenlafaxine affect both neurotransmitter systems, which distinguishes them as a separate pharmacologic class 4
Clinical Classification Context
- The American College of Physicians categorizes desvenlafaxine among second-generation antidepressants, specifically within the SNRI subclass alongside venlafaxine, duloxetine, milnacipran, and levomilnacipran 4
- SNRIs are distinguished from SSRIs (like fluoxetine, sertraline, paroxetine) and other second-generation antidepressants (like bupropion and mirtazapine) based on their dual mechanism of action 4
- The FDA label explicitly states that desvenlafaxine "belongs to a class of medicines known as serotonin and norepinephrine reuptake inhibitors (SNRIs)" 1
Important Clinical Distinction
- While desvenlafaxine is chemically the active metabolite of venlafaxine, it is formulated and approved as a separate SNRI medication with its own dosing recommendations (50-100 mg daily) 1, 5
- The SNRI classification carries specific clinical implications, including potential for blood pressure elevation, different side effect profile compared to SSRIs, and risk of serotonin syndrome when combined with other serotonergic agents 4, 1, 2