Are Trazodone, Buspirone, Namenda (Memantine), Trintellix (Vortioxetine), and Ativan (Lorazepam) contraindicated in patients with bradycardia?

Medication Safety with Bradycardia

Trazodone is the only medication in your list that is potentially problematic with bradycardia, as it is specifically contraindicated in patients with symptomatic bradycardia according to its FDA label. The other medications (Namenda XR, Trintellix, Buspirone, and Ativan) do not have specific contraindications for bradycardia.

Detailed Analysis of Each Medication

Trazodone (150 mg PO QHS)

• Safety concern: Trazodone is contraindicated in patients with symptomatic bradycardia 1
• The FDA label specifically states: "Trazodone Hydrochloride Tablets should be avoided in patients with a history of cardiac arrhythmias, as well as other circumstances that may increase the risk of the occurrence of torsade de pointes and/or sudden death, including symptomatic bradycardia" 1
• Trazodone can be arrhythmogenic in patients with pre-existing cardiac disease, with reported cases of torsade de pointes at doses of 100 mg or less 1
• Older studies suggested trazodone may have less cardiotoxicity than tricyclic antidepressants, but caution is still advised in patients with ventricular irritability 2

Namenda XR (Memantine 28 mg PO QAM)

• No specific contraindications or warnings related to bradycardia in available guidelines
• Primarily excreted renally, with minimal metabolism through the cytochrome P450 system
• Not known to significantly affect cardiac conduction or heart rate

Trintellix (Vortioxetine 20 mg PO QAM)

• No specific contraindications for bradycardia in available guidelines
• Vortioxetine is an antagonist at 5-HT3, 5-HT1D, and 5-HT7 receptors, an agonist at 5-HT1A receptors, and a partial agonist at 5-HT1B receptors 3
• Common adverse effects include nausea, constipation, and vomiting, but not cardiac conduction abnormalities 3

Buspirone (15 mg PO TID)

• No specific contraindications for bradycardia in available guidelines
• Not known to significantly affect cardiac conduction or heart rate
• Has a favorable cardiovascular profile compared to many other psychotropic medications

Ativan (Lorazepam 0.5 mg PO TID)

• No specific contraindications for bradycardia in available guidelines
• Benzodiazepines generally have minimal direct effects on cardiac conduction
• May cause sedation and CNS depression but not typically associated with bradycardia

Risk Factors and Considerations

1. Pre-existing cardiac conditions: Patients with pre-existing cardiac disease, conduction disorders, or sinus node dysfunction are at higher risk for medication-induced bradycardia 4

2. Drug interactions: The combination of medications that affect heart rate can increase the risk of bradycardia. For example:

   • If the patient is also taking beta-blockers, calcium channel blockers, or digoxin, the risk of bradycardia with trazodone may be increased 5, 6
   • The European Society of Cardiology notes that bradyarrhythmias are common pharmacological effects of digoxin, verapamil, diltiazem, and beta-blockers 5

3. Age: Advanced age increases susceptibility to drug-induced bradycardia due to decreased drug metabolism and clearance 4

Recommendations

1. Consider alternative to trazodone if the patient has symptomatic bradycardia or is at high risk for cardiac arrhythmias

2. Monitor cardiac function:

   • Baseline ECG before starting trazodone
   • Follow-up ECG after initiating treatment
   • Monitor for symptoms of worsening bradycardia (dizziness, lightheadedness, syncope, fatigue)

3. Dose considerations:

   • If trazodone must be used, consider starting at a lower dose (50-100 mg)
   • The current dose of 150 mg may increase risk in susceptible patients

4. Drug interaction precautions:

   • Avoid adding other medications that can cause or worsen bradycardia
   • Be particularly cautious with any antiarrhythmic medications

Summary

Among the medications listed (Namenda XR, Trintellix, Buspirone, Trazodone, and Ativan), only trazodone carries a specific contraindication for use in patients with symptomatic bradycardia according to its FDA label. The other medications do not have specific warnings regarding bradycardia in the available evidence. If the patient has bradycardia, consider alternatives to trazodone or close monitoring if trazodone must be continued.