Yes, vilazodone can cause you to feel like you are going to pass out
Vilazodone is explicitly listed in the FDA drug label as causing dizziness, and more seriously, can cause fainting as part of serotonin syndrome or due to blood pressure changes. 1
Direct Evidence from FDA Labeling
The FDA-approved prescribing information for vilazodone specifically warns about:
- Dizziness as a symptom of serotonin syndrome, along with blood pressure changes 1
- Fainting listed explicitly as a severe symptom of hyponatremia (low sodium levels) 1
- Dizziness as a discontinuation syndrome symptom if the medication is stopped suddenly 1
The drug label instructs patients not to drive or operate heavy machinery until they know how vilazodone affects them, specifically because it "can cause sleepiness or may affect your ability to make decisions, think clearly, or react quickly" 1
Mechanism and Clinical Context
The sensation of impending syncope (presyncope) with vilazodone occurs through several pathways:
Serotonin syndrome is the most concerning mechanism. Vilazodone can trigger this potentially life-threatening condition, which includes:
- Blood pressure changes (both increases and decreases)
- Dizziness
- Fast heart rate
- Confusion and altered mental status 1
Research confirms that vilazodone, unlike typical SSRIs, frequently causes serotonin syndrome even in single-substance ingestions 2. This is particularly important because vilazodone acts both as a serotonin reuptake inhibitor AND a 5-HT1A partial agonist, potentially causing more rapid and severe serotonergic effects 3, 2.
Hyponatremia (low sodium) is another mechanism explicitly listed in the FDA label that can cause fainting. The label warns this can be serious and potentially fatal, with elderly patients at higher risk 1.
What to Watch For
If you experience a feeling like you're going to pass out while taking vilazodone, evaluate for these warning signs:
Immediate emergency symptoms (serotonin syndrome):
- Agitation or confusion
- Fast heartbeat
- Sweating or flushing
- High body temperature
- Muscle stiffness or twitching
- Nausea, vomiting, or diarrhea 1
Hyponatremia symptoms:
- Headache
- Confusion or memory changes
- Weakness and unsteadiness
- In severe cases: hallucinations, fainting, seizures 1
Clinical Action
Stop vilazodone immediately and seek emergency care if you experience presyncope symptoms along with any signs of serotonin syndrome or severe hyponatremia 1. The FDA label explicitly instructs patients to "go to the nearest hospital emergency room right away" if serotonin syndrome is suspected 1.
For isolated dizziness or presyncope without other concerning symptoms, contact your healthcare provider promptly. Do not stop the medication abruptly on your own, as sudden discontinuation can also cause dizziness as part of discontinuation syndrome 1.
Important Caveat
The risk increases substantially if you're taking vilazodone with other serotonergic medications (other antidepressants, triptans, St. John's Wort, tramadol) or medications affecting blood clotting 1. Always inform your provider of all medications you're taking.