Medical emergency
Irregular heartbeat or fainting (QT prolongation)
Trazodone can affect the heart's electrical rhythm in a way that, in rare cases, leads to a dangerous or fainting-inducing arrhythmia.
Editorially reviewed
This can be a medical emergency. If you notice these signs in yourself or someone else, call 911 (US) or go to the nearest emergency room immediately. Do not wait to see if it passes.
Key points
- Risk rises with higher doses and other QT-prolonging drugs
- Mention any personal/family arrhythmia history before starting
- Irregular heartbeat with fainting needs prompt evaluation
Trazodone's Medication Guide specifically lists "irregular or fast heartbeat or faint (QT prolongation)" among the serious risks patients should know about. This risk is higher at higher doses, with other QT-prolonging medications, or in people with existing heart rhythm conditions or electrolyte imbalances.
Anyone who experiences a racing, irregular, or pounding heartbeat combined with dizziness or fainting while taking trazodone should seek prompt medical evaluation, and mention any personal or family history of heart rhythm problems before starting the medication.
Call your prescriber or seek care if you notice:
- Racing, pounding, or irregular heartbeat
- Fainting or near-fainting associated with heart palpitations
Not medical advice. This page describes general patterns reported for trazodone and does not replace individualized guidance from your prescriber or pharmacist.
