What is the protocol for switching from citalopram (Selective Serotonin Reuptake Inhibitor - SSRI) to sertraline (SSRI)?

Protocol for Switching from Citalopram to Sertraline

When switching between SSRIs like citalopram and sertraline, use a direct cross-taper approach: start sertraline at 25 mg/day while maintaining the current citalopram dose, then gradually taper citalopram by 50% after 3-7 days, and discontinue citalopram completely after another 3-7 days of overlap. 1

Initial Cross-Taper Strategy

Begin sertraline at 25 mg/day while continuing the current citalopram dose for 3-7 days. 2 This overlap period allows sertraline to begin reaching therapeutic levels while maintaining antidepressant coverage and minimizing withdrawal symptoms. 1

• The starting dose of 25 mg for sertraline is the recommended initial dose in adolescents and is appropriate for adults as well 2
• Continue both medications simultaneously during this initial overlap period to prevent treatment gaps 1

Citalopram Taper Phase

After 3-7 days of overlap, reduce citalopram by 50% while maintaining sertraline at 25 mg/day. 1 Continue this reduced citalopram dose for another 3-7 days before complete discontinuation.

• All SSRIs must be slowly tapered when discontinued due to risk of withdrawal effects 2
• Citalopram has a shorter half-life than fluoxetine, making gradual tapering essential to avoid discontinuation syndrome 2
• Abrupt discontinuation can cause withdrawal symptoms including dizziness, fatigue, nausea, headaches, sensory disturbances, and anxiety 2

Sertraline Titration

After citalopram is fully discontinued, maintain sertraline at 25 mg/day for at least 1-2 weeks before considering dose increases. 2

• Increase sertraline in increments of 12.5-25 mg at 1-2 week intervals as tolerated 2
• The effective dose range for sertraline is typically 50 mg/day, with a maximum of 200 mg/day 2
• Evidence from the STAR*D trial shows that switching between SSRIs (including from citalopram to sertraline) produces similar efficacy outcomes 2

Critical Monitoring During the Switch

Monitor closely for serotonin syndrome during the overlap period, particularly in the first 24-48 hours after starting sertraline. 2, 1 Watch for:

• Mental status changes: confusion, agitation, anxiety 2, 1
• Neuromuscular hyperactivity: tremors, clonus, hyperreflexia, muscle rigidity 2
• Autonomic hyperactivity: hypertension, tachycardia, tachypnea, diaphoresis 2, 1

Assess for early adverse effects from sertraline including nausea, headache, insomnia, nervousness, and gastrointestinal symptoms. 1 Sertraline is associated with discontinuation syndrome if stopped abruptly, so plan for gradual tapering if future medication changes are needed. 2

Safety Considerations and Contraindications

Never combine either citalopram or sertraline with MAOIs due to severe risk of serotonin syndrome. 2, 1 A minimum washout period is required when switching to or from MAOIs.

• Monitor for abnormal bleeding, especially if the patient takes aspirin or NSAIDs, as both SSRIs increase bleeding risk 2, 1
• Be aware that citalopram can cause QT prolongation at doses exceeding 40 mg/day, while sertraline has less QT risk 2
• Both medications may interact with drugs metabolized by CYP2D6 2

Follow-Up Schedule

Maintain close contact (in-person or telephone) during the first 4 weeks of the switch to monitor for clinical worsening, suicidality, and unusual behavioral changes. 2, 1

• Contact should occur within the first week after initiating the switch 2
• Monitor particularly closely during dose changes, either increases or decreases 2
• Assess adherence to the switching protocol and patient understanding of the treatment plan 2
• Younger patients require especially vigilant monitoring for behavioral activation and suicide-related events 2, 1

Expected Outcomes

Approximately 20-30% of patients who switch from one SSRI to another after inadequate response will achieve remission. 2, 3 The STAR*D trial found no significant differences in efficacy between switching to sertraline versus other SSRIs like bupropion or venlafaxine. 2

• Allow at least 6 weeks to assess response, though up to 12 weeks may be needed to capture all potential responders 3
• Patients showing at least 20% symptom reduction by week 2 are 6 times more likely to ultimately respond or remit 3
• If switching due to tolerability issues rather than lack of efficacy, success rates are higher, with 87% completing treatment and 56-62% responding 4