What augmentation options can be added to mirtazapine (Remeron) for a severely depressed, suicidal patient?

Augmentation of Mirtazapine for Severe Depression with Suicidal Ideation

Primary Recommendation: Bupropion SR Augmentation

Add bupropion SR 150 mg once daily, increasing to 150 mg twice daily (300 mg total) after 3 days if tolerated, as this provides complementary norepinephrine-dopamine reuptake inhibition to mirtazapine's noradrenergic and serotonergic enhancement. 1, 2

Evidence Supporting Bupropion Augmentation

• In the STAR*D trial, bupropion augmentation of citalopram achieved remission rates of approximately 30% in treatment-resistant depression, with significantly lower discontinuation rates (12.5%) compared to buspirone augmentation (20.6%; P < 0.001). 1, 3

• Bupropion augmentation decreases depression severity more effectively than buspirone augmentation in patients who failed initial antidepressant monotherapy. 3

• The combination addresses both motivational deficits (via dopamine/norepinephrine) and mood symptoms (via mirtazapine's serotonergic activity) through complementary mechanisms without significant pharmacokinetic interactions. 3, 4

Dosing Protocol

• Start bupropion SR at 150 mg once daily for 3 days, then increase to 150 mg twice daily (300 mg total). 2

• Administer the second dose before 3 PM to minimize insomnia risk, as bupropion has activating properties. 2

• Maximum dose should not exceed 450 mg/day to maintain seizure risk at approximately 0.1%. 3, 2

Critical Safety Monitoring for Suicidal Patients

• Assess suicidal ideation at every patient contact during the first 1-2 months after augmentation, as suicide risk is greatest during the initial treatment period and after medication changes. 3

• Evaluate treatment response every 2-4 weeks using standardized depression rating scales (PHQ-9 or HAM-D) to objectively track symptom change. 3

• Allow 6-8 weeks at the optimized bupropion dose before declaring treatment failure, as full antidepressant response may require this duration. 1, 3

Absolute Contraindications to Bupropion

• History of seizure disorders or any condition predisposing to seizures (head trauma, brain tumor, stroke). 2

• Current or recent MAOI use (within 14 days). 2

• Eating disorders (bulimia or anorexia nervosa) due to increased seizure risk. 2

• Uncontrolled hypertension, as bupropion can elevate blood pressure and heart rate. 3, 2

• Abrupt discontinuation of alcohol, benzodiazepines, or antiepileptic drugs. 2

Alternative Augmentation Strategy: Aripiprazole

If bupropion is contraindicated, add aripiprazole as the next evidence-based augmentation option. 3

• One trial (high risk of bias) reported higher remission rates with aripiprazole augmentation (55.4%) versus bupropion (34.0%; P = 0.031), though discontinuation rates were similar (0% vs 0%). 1

• Aripiprazole is particularly effective for patients with persistent motivational deficits and apathy despite optimized mirtazapine dosing. 3

Adjunctive Psychotherapy (Initiate Immediately)

Add individual cognitive-behavioral therapy (CBT) immediately while optimizing medication, as combination pharmacologic-psychologic treatment demonstrates superior efficacy compared to medication alone. 1, 3

• CBT can be started without waiting for medication optimization, providing early psychological support for patients with suicidal ideation. 3

• The STAR*D trial demonstrated similar efficacy between bupropion augmentation, buspirone augmentation, and cognitive therapy augmentation of citalopram. 1

Switching Strategy (If Augmentation Fails After 8 Weeks)

If adequate response is not achieved after 8 weeks of optimized augmentation therapy, switch to an SNRI—either venlafaxine extended-release (150-225 mg daily) or duloxetine (40-120 mg daily). 3

• SNRIs demonstrate statistically significant superior response and remission rates compared to SSRIs in treatment-resistant depression. 3

• The American College of Physicians found no significant difference between switching and augmenting strategies overall, with approximately 25% of patients achieving remission after a switch. 1, 3

Mirtazapine-Specific Considerations

• Mirtazapine demonstrates rapid onset of action compared to SSRIs, with superior efficacy at weeks 1-2 versus paroxetine and citalopram, and weeks 3-4 versus fluoxetine. 5, 6

• Mirtazapine is particularly beneficial for patients with depression accompanied by anxiety symptoms, sleep disturbance, or low appetite, due to its antihistaminic and anxiolytic properties. 4, 5, 6

• Ensure mirtazapine is optimized to 30-45 mg daily before adding augmentation, as therapeutic doses are required for full noradrenergic and serotonergic effects. 6

Duration of Continuation Therapy

• After achieving satisfactory response, continue treatment for 4-9 months for a first episode of major depressive disorder. 3

• For patients with recurrent depression (≥2 episodes), consider maintenance therapy for years to lifelong to prevent relapse. 3

Critical Pitfalls to Avoid

• Do not switch medications before completing an adequate 6-8 week trial at therapeutic doses, as premature changes delay recovery and miss opportunities for response. 1, 3

• Do not continue ineffective treatment beyond 8 weeks; guideline-recommended reassessment occurs at 6-8 weeks. 1, 3

• Do not exceed bupropion 450 mg/day, as seizure risk increases markedly above this threshold. 3, 2

• Do not combine bupropion with MAOIs or initiate within 14 days of MAOI discontinuation. 2