Can bupropion (Wellbutrin) be added to a regimen of citalopram 40 mg?

Can Bupropion (Wellbutrin) Be Added to Citalopram 40 mg?

Yes, bupropion can be safely added to citalopram 40 mg as an augmentation strategy for treatment-resistant depression, and this combination is supported by both FDA drug labeling data and clinical evidence.

Key Safety Considerations from FDA Labeling

The FDA label for Wellbutrin specifically addresses this combination 1. Bupropion increased citalopram levels by 30% (Cmax) and 40% (AUC) in pharmacokinetic studies 1. However, importantly, citalopram did not affect bupropion pharmacokinetics 1. This is a manageable interaction that does not contraindicate combination use.

Critical Safety Points:

• Monitor for serotonin syndrome: While the risk is lower than with MAOIs, combining two serotonergic agents requires vigilance for symptoms (confusion, agitation, tremors, tachycardia, diaphoresis) especially in the first 24-48 hours after starting bupropion 2
• Seizure risk: Bupropion lowers seizure threshold; avoid in patients with seizure disorders or eating disorders 3
• Cardiovascular monitoring: Monitor blood pressure and heart rate, as both medications can affect these parameters 4
• QT prolongation: Citalopram at 40 mg is at the maximum FDA-approved dose and carries QT prolongation risk; avoid additional QT-prolonging drugs 2

Clinical Evidence Supporting This Combination

Augmentation Strategy Evidence

The STAR*D trial—the largest and highest-quality study on treatment-resistant depression—directly compared augmentation strategies 5, 6. Augmenting citalopram with bupropion showed similar efficacy to augmenting with buspirone or cognitive therapy 5. Critically, discontinuation due to adverse events was significantly lower with bupropion (12.5%) compared to buspirone (20.6%; P < 0.001) 5.

A smaller naturalistic study found that combining citalopram and bupropion-SR was superior to switching to monotherapy, with better SIGH-SAD change scores (-14.8 vs -10.1, p <.04) and higher remission rates (28% vs 7%, p <.05) 7. The combination was well-tolerated with no greater side effect burden than monotherapy 7.

Mechanism and Rationale

This combination targets multiple neurotransmitter systems: citalopram inhibits serotonin reuptake while bupropion inhibits dopamine and norepinephrine reuptake 8. Bupropion is particularly effective for symptoms of hypersomnia, increased appetite, weight gain, and fatigue—symptoms that may persist despite SSRI treatment 9.

Practical Dosing Algorithm

Starting bupropion augmentation:

1. Continue citalopram 40 mg (patient is already at maximum dose)
2. Start bupropion SR 150 mg once daily in the morning 3
3. After 3-7 days, increase to 150 mg twice daily (second dose before 3 PM to minimize insomnia) 3
4. Maximum dose: 300 mg/day (150 mg twice daily) for augmentation purposes

Monitoring schedule:

• Week 1-2: Assess for activation symptoms, insomnia, anxiety, tremor
• Week 2-4: Monitor blood pressure, heart rate, and emerging serotonergic symptoms
• Week 4-8: Assess antidepressant response using standardized scales
• Ongoing: Monitor for seizure risk factors, cardiovascular parameters

Common Pitfalls to Avoid

1. Don't give the second bupropion dose after 3 PM—this significantly increases insomnia risk 3
2. Don't use in agitated patients—bupropion is activating and can worsen agitation 3
3. Don't combine with MAOIs—must wait 14 days after MAOI discontinuation 1
4. Don't ignore the increased citalopram levels—the 30-40% increase in citalopram exposure means monitoring for SSRI side effects (GI symptoms, sexual dysfunction, activation) is essential 1
5. Screen for eating disorders—bupropion is contraindicated due to seizure risk 4, 10

When This Combination Is Particularly Appropriate

Based on recent evidence, prioritize this combination for patients with 9:

• Hypersomnia or excessive daytime sleepiness
• Increased appetite or weight gain on citalopram
• Persistent fatigue or low energy
• SSRI-induced sexual dysfunction (bupropion can ameliorate this) 8
• Comorbid smoking cessation needs 4

Alternative Consideration

If the patient has prominent insomnia, decreased appetite, or weight loss, mirtazapine would be a more appropriate augmentation choice than bupropion 9. The symptom profile should guide augmentation selection.