Can I start Lexapro (escitalopram) 10mg daily in a patient on Wellbutrin SR (bupropion) 150mg BID with a history of atrial fibrillation (A-Fib)?

Can You Start Lexapro 10mg Daily in This Patient?

Yes, you can start Lexapro (escitalopram) 10mg daily in a patient on Wellbutrin SR 150mg BID with atrial fibrillation, but you must monitor for serotonin syndrome and ensure the patient's A-Fib is adequately rate-controlled before initiating treatment.

Key Drug Interaction Considerations

There is no absolute contraindication to combining bupropion (Wellbutrin) and escitalopram (Lexapro). These medications work through different mechanisms—bupropion primarily affects norepinephrine and dopamine, while escitalopram is a selective serotonin reuptake inhibitor 1. However, you should:

• Monitor for serotonin syndrome when combining any antidepressants, though the risk is lower with this combination than with multiple serotonergic agents 1
• Watch for increased anxiety or insomnia initially, as both medications can cause these side effects 2, 3
• Counsel the patient about potential additive CNS effects and avoid alcohol 1

Atrial Fibrillation Management Considerations

Before starting Lexapro, verify that the patient's A-Fib is adequately rate-controlled:

• Ensure resting heart rate is controlled (target <110 bpm for lenient control) using beta-blockers or calcium channel antagonists as first-line agents 4
• Assess if the patient is on appropriate anticoagulation based on CHA₂DS₂-VASc score, as this is independent of antidepressant therapy 4

Escitalopram does not directly interact with common A-Fib medications (beta-blockers, calcium channel blockers, digoxin, or anticoagulants), but you should:

• Avoid combining with QT-prolonging agents like certain antiarrhythmics (dofetilide, ibutilide, quinidine) due to additive QT prolongation risk 4
• Check baseline ECG if the patient is on multiple QT-prolonging medications 1

Cardiovascular Safety Profile

Bupropion has been studied in patients with cardiac disease and shows a favorable cardiovascular profile:

• Does not cause significant conduction complications or exacerbate ventricular arrhythmias 5
• May cause mild supine blood pressure elevation but has low rates of orthostatic hypotension 5
• Monitor blood pressure as bupropion can exacerbate baseline hypertension in some patients 5

Escitalopram is generally cardiovascularly safe but requires monitoring for:

• QT prolongation (avoid use with pimozide per FDA labeling) 1
• Bleeding risk if combined with anticoagulants—counsel about increased bruising/bleeding 1

Practical Implementation Algorithm

Follow this sequence:

1. Verify A-Fib rate control is adequate (resting HR <110 bpm or <80 bpm if symptomatic) 4
2. Review current medications for QT-prolonging agents and anticoagulation status 1
3. Start Lexapro 10mg daily (can be taken with or without food, morning or evening) 1
4. Schedule follow-up in 1-2 weeks to assess for side effects, particularly insomnia, anxiety, or GI upset 1
5. Monitor for serotonin syndrome symptoms (agitation, confusion, rapid heart rate, muscle rigidity) especially in first 2 weeks 1

Critical Pitfalls to Avoid

• Do not combine with MAOIs or start within 2 weeks of MAOI discontinuation 1
• Do not use with pimozide due to serious cardiac arrhythmia risk 1
• Do not assume A-Fib is controlled—verify rate control before adding any medication that could affect cardiovascular stability 4
• Do not ignore bleeding risk if patient is on warfarin or DOACs—counsel about increased bleeding tendency with SSRIs 1

Monitoring Parameters

• Week 1-2: Assess for insomnia, anxiety, nausea, and serotonin syndrome symptoms 1
• Week 4: Evaluate therapeutic response and side effect tolerability 1
• Ongoing: Monitor heart rate control if patient reports palpitations or worsening A-Fib symptoms 4
• If on anticoagulation: Counsel about increased bleeding risk and monitor for bruising 1