Is Viibryd an Amphetamine?
No, Viibryd (vilazodone) is definitively not an amphetamine—it is a selective serotonin reuptake inhibitor (SSRI) with 5-HT1A receptor partial agonist properties, approved exclusively for major depressive disorder in adults. 1, 2
Drug Classification and Mechanism
Vilazodone belongs to an entirely different pharmacological class than amphetamines:
Vilazodone is classified as an SSRI antidepressant that enhances serotonergic activity through selective inhibition of serotonin reuptake, with no significant effects on norepinephrine or dopamine reuptake 1, 3
It additionally acts as a partial agonist at 5-HT1A receptors, which theoretically enhances serotonergic neurotransmission and contributes to its antidepressant effects 1, 2
Vilazodone is NOT a controlled substance according to FDA labeling, whereas amphetamines are Schedule II controlled substances due to their high abuse potential 1
Chemical Structure and Properties
Vilazodone's molecular formula is C26H27N5O2·HCl with a molecular weight of 477.99 g/mol—chemically unrelated to amphetamine structures 1
The drug binds with high affinity to the serotonin reuptake site (Ki=0.1 nM) but has minimal affinity for norepinephrine (Ki=56 nM) or dopamine (Ki=37 nM) reuptake sites 1
Systematic studies in animals demonstrated no abuse or dependence potential, and clinical trials showed no evidence of drug-seeking behavior 1
Important Clinical Distinction: False-Positive Amphetamine Screening
A critical caveat: vilazodone overdose can cause false-positive amphetamine results on urine drug screens 4
In a documented case report, a toddler with confirmed vilazodone overdose tested positive on initial amphetamine screening (Amphetamines II assay), but confirmatory testing by gas chromatography-mass spectrometry was negative 4
This false-positive phenomenon should be investigated when vilazodone overdose is suspected to avoid misdiagnosis 4
Approved Indications
Vilazodone is FDA-approved exclusively for major depressive disorder in adults, with typical dosing of 40 mg once daily 1, 2
It has no approved or off-label use for ADHD, unlike amphetamines which are first-line stimulant treatments for ADHD 5, 6
Comparison to Actual Amphetamines
For context, amphetamines (like Adderall) work through completely different mechanisms:
Amphetamines are dopamine and norepinephrine releasing agents and reuptake inhibitors—not serotonin-focused medications 5, 6
They are Schedule IV controlled substances with significant abuse potential requiring careful monitoring 6, 7
Amphetamines are used primarily for ADHD and narcolepsy, not depression 5, 6