What is the recommended tapering and washout protocol for switching from a selective serotonin reuptake inhibitor (SSRI) to a monoamine oxidase inhibitor (MAOI)?

Tapering Protocol for Switching from SSRI to MAOI

Concomitant administration of any SSRI with any MAOI is absolutely contraindicated due to the risk of potentially fatal serotonin syndrome, requiring a complete washout period before initiating MAOI therapy. 1

Mandatory Washout Protocol

Standard SSRIs (Sertraline, Citalopram, Escitalopram, Paroxetine, Fluvoxamine)

Discontinue the SSRI completely and wait a minimum of 2 weeks (14 days) before starting any MAOI. 2, 3 This washout period allows for:

• Complete elimination of the SSRI from the system
• Clearance of active metabolites
• Restoration of normal serotonin receptor function

Fluoxetine (Special Case)

Fluoxetine requires a minimum 5-week (35-day) washout period before initiating an MAOI due to its exceptionally long half-life and active metabolite (norfluoxetine). 2, 3 This extended washout is non-negotiable given fluoxetine's prolonged presence in the system.

Tapering the SSRI Before Washout

Gradually taper the SSRI over 1-2 weeks before the washout period begins to minimize discontinuation syndrome, particularly for:

• Paroxetine (highest risk)
• Fluvoxamine (moderate risk)
• Sertraline (moderate risk)

1, 4

The taper reduces risk of discontinuation symptoms including dizziness, nausea, paresthesias, anxiety, and flu-like symptoms. However, the washout clock does not start until the SSRI is completely stopped.

Critical Safety Monitoring

During the washout period, monitor for:

Discontinuation syndrome symptoms:

• Dizziness, vertigo, imbalance
• Nausea, vomiting, diarrhea
• Paresthesias, sensory disturbances
• Anxiety, irritability, agitation
• Headaches, myalgias, fatigue

1

Worsening depression: The patient will be without antidepressant coverage during washout. Close monitoring for suicidality and clinical deterioration is essential, especially in the first 2-4 weeks. 4

Why This Protocol is Non-Negotiable

Serotonin syndrome can be fatal and occurs when serotonergic medications are combined. 1 Symptoms include:

• Mental status changes (confusion, agitation)
• Neuromuscular hyperactivity (tremors, clonus, hyperreflexia, rigidity)
• Autonomic instability (hypertension, tachycardia, hyperthermia, diaphoresis)
• Advanced cases: seizures, arrhythmias, unconsciousness, death

Treatment requires hospitalization with discontinuation of all serotonergic agents and intensive supportive care. 1

Common Pitfalls to Avoid

1. Never attempt a direct switch or cross-taper between an SSRI and MAOI - this is the most dangerous switching scenario in psychopharmacology 2, 3

2. Do not count tapering time as washout time - the full washout period begins only after complete SSRI discontinuation

3. Do not underestimate fluoxetine's duration - its 5-week requirement is based on pharmacokinetics, not clinical judgment 2

4. Avoid all serotonergic medications during washout including tramadol, meperidine, dextromethorphan, St. John's wort, and triptans 1, 5

Clinical Algorithm

1. Week 1-2: Gradually taper SSRI (except fluoxetine, which can be stopped abruptly given its long half-life)
2. Week 2: Complete SSRI discontinuation - washout period begins
3. Week 2-4 (or 2-7 for fluoxetine): Medication-free washout with close monitoring
4. Week 4+ (or Week 7+ for fluoxetine): Safe to initiate MAOI at standard starting doses

This conservative approach prioritizes patient safety over treatment continuity, as the mortality risk of serotonin syndrome far outweighs the temporary gap in antidepressant coverage.