Viibryd Drug Classification
Viibryd (vilazodone) is classified as a selective serotonin reuptake inhibitor (SSRI) and 5-HT1A receptor partial agonist—a dual-mechanism antidepressant approved for the treatment of major depressive disorder in adults. 1
Pharmacological Classification
Primary Mechanism:
- SSRI Component: Vilazodone selectively inhibits serotonin reuptake at the presynaptic transporter (Ki = 0.1 nM), enhancing serotonergic neurotransmission in the central nervous system 1
- 5-HT1A Partial Agonist: Vilazodone binds with high affinity to 5-HT1A receptors (IC50 = 2.1 nM) and acts as a partial agonist at these sites 1
Receptor Selectivity:
- Vilazodone demonstrates high selectivity for serotonin reuptake inhibition with minimal activity at norepinephrine (Ki = 56 nM) or dopamine (Ki = 37 nM) reuptake sites 1
- This dual mechanism distinguishes vilazodone from traditional SSRIs, potentially offering faster onset of action and improved tolerability 2, 3
Regulatory Classification
FDA Approval Status:
- Approved by the U.S. Food and Drug Administration in January 2011 for the treatment of major depressive disorder in adults 4
- Not a controlled substance under the Comprehensive Drug Abuse Prevention and Control Act 1
- Vilazodone has not demonstrated abuse or dependence potential in systematic animal studies 1
Clinical Classification Context
Antidepressant Category:
- The World Health Organization classifies similar dual-mechanism agents as N06AX antidepressants (other antidepressants) 3
- Vilazodone does not fit into traditional antidepressant classes (tricyclics, MAOIs, or standard SSRIs) due to its unique dual pharmacology 3, 5
Distinguishing Features:
- Unlike pure SSRIs, the 5-HT1A partial agonist activity may contribute to reduced sexual side effects and potentially faster therapeutic onset compared to traditional SSRIs 3, 4
- The combination of SSRI and 5-HT1A receptor modulation represents a novel approach to enhancing serotonergic activity beyond simple reuptake inhibition 5