Can trazodone (antidepressant) cause tachycardia?

Can Trazodone Cause Tachycardia?

Yes, trazodone can cause tachycardia, though it more commonly causes bradycardia or other cardiac arrhythmias including QT prolongation, ventricular tachycardia, and torsades de pointes, particularly in overdose situations or patients with cardiac risk factors. 1

Cardiac Arrhythmia Profile

Tachycardia as a Direct Effect

• Tachycardia is a recognized adverse effect of trazodone, occurring as part of serotonin syndrome when autonomic instability develops, manifesting as tachycardia, labile blood pressure, diaphoresis, and hyperthermia 1
• In clinical trials, tachycardia/palpitations occurred in <2% of patients taking therapeutic doses of trazodone 1
• Post-marketing surveillance has documented tachycardia as an adverse cardiac event, though less frequently than other arrhythmias 1
• In a large poison center database analysis of 118,773 trazodone exposures, tachycardia occurred in 7.0% of cases, making it one of the more common cardiac manifestations 2

More Common Cardiac Effects

• The FDA label explicitly warns that trazodone may be arrhythmogenic in patients with preexisting cardiac disease, with identified arrhythmias including isolated PVCs, ventricular couplets, ventricular tachycardia with syncope, and torsades de pointes 1
• Bradycardia is actually more commonly reported than tachycardia in long-term studies, with symptomatic bradycardia documented even after single low doses (50 mg) 1, 3
• QT/QTc prolongation is a significant concern, with torsades de pointes reported at doses as low as 100 mg or less 1

High-Risk Clinical Scenarios

Overdose Situations

• Trazodone has been implicated in torsades de pointes specifically in overdose situations, as documented by the American Heart Association 4, 5
• In severe overdose cases, patients can develop a progression of arrhythmias including ventricular tachycardia, right bundle-branch block, left anterior fascicular block, and variable degrees of AV nodal blocks occurring 12-24 hours post-ingestion 6
• The median ingested dose associated with ICU admission was 1500 mg compared to 600 mg for emergency department treatment and release 2

Serotonin Syndrome

• When tachycardia occurs with trazodone, it is most commonly part of serotonin syndrome, which presents with autonomic instability including tachycardia as a cardinal feature 1
• Risk increases substantially with concomitant use of other serotonergic drugs (triptans, SSRIs, SNRIs, fentanyl, tramadol, lithium) or MAOIs 1

Patients Requiring Caution

Cardiac Risk Factors

• Trazodone should be avoided in patients with:
  • History of cardiac arrhythmias 1
  • Known QT prolongation or congenital long QT syndrome 1
  • Symptomatic bradycardia 1
  • Hypokalemia or hypomagnesemia 1
  • Recent myocardial infarction (not recommended during initial recovery phase) 1
  • Preexisting cardiac disease requiring close monitoring 1

Drug Interactions Increasing Arrhythmia Risk

• Avoid trazodone with CYP3A4 inhibitors (itraconazole, clarithromycin, voriconazole) which increase trazodone levels and arrhythmia risk 1
• Avoid combination with other QT-prolonging drugs including Class IA antiarrhythmics (quinidine, procainamide), Class III antiarrhythmics (amiodarone, sotalol), certain antipsychotics (ziprasidone, chlorpromazine, thioridazine), and certain antibiotics (gatifloxacin) 1

Clinical Monitoring Recommendations

• Baseline ECG is mandatory before initiating trazodone in patients with any cardiac risk factors 7
• Follow-up ECG within 30 days of initiation for high-risk patients 7
• Monitor electrolytes (potassium and magnesium) particularly in patients at risk for disturbances 7
• Close cardiac monitoring is essential for patients with preexisting cardiac disease, as antidepressant drugs including trazodone may cause cardiac arrhythmias 1

Comparative Safety Context

• Among antidepressants, SNRIs demonstrate the lowest cardiac risk and should be considered first-line when cardiac safety is a concern, while trazodone carries moderate risk particularly in overdose 7
• Trazodone's cardiac effects are generally less severe than tricyclic antidepressants at therapeutic doses, but can be significant in overdose or high-risk patients 8, 2