How to taper citalopram (Celexa) while starting fluoxetine (Prozac)?

How to Taper Citalopram While Starting Fluoxetine

Gradually taper citalopram by reducing the dose by 25% of the current dose every 1-2 weeks until reaching the lowest available dose (typically 10 mg), then start fluoxetine at 10 mg every other morning after citalopram is completely discontinued or at a very low dose. 1

Citalopram Tapering Protocol

Reduction Schedule

• Reduce citalopram by 25% of the current dose every 1-2 weeks (for example: 40 mg → 30 mg → 22.5 mg → 17 mg → 12.5 mg → 10 mg) 1
• Continue tapering until reaching the lowest available dose, typically 10 mg for citalopram 1
• The taper rate must be determined by the patient's ability to tolerate reductions, not by a rigid schedule 2

Managing Withdrawal Symptoms

• If withdrawal symptoms occur (dizziness, nausea, fatigue, anxiety, sensory disturbances), slow the taper rate or temporarily return to the previous dose until symptoms subside 1, 3
• Withdrawal symptoms should be preempted and treated with liberal use of adjuvant agents (such as trazodone for insomnia) along with adequate clinician support 1
• Gradual tapering is necessary for all SSRIs except fluoxetine, which has an extended half-life 3

Important Considerations for SSRI Tapering

• Studies show that hyperbolic (exponential) tapering down to doses much lower than minimum therapeutic doses has shown greater success in reducing withdrawal symptoms compared to standard short tapers 4
• Withdrawal symptoms frequently emerge after abrupt discontinuation and are generally mild and self-limiting but can be distressing and lead to missed work days 3
• Symptoms may be somatic (dizziness, nausea, fatigue, flu-like symptoms, sensory disturbances) or psychological (anxiety, irritability, crying spells) 3

Initiating Fluoxetine

Starting Dose and Timing

• Start fluoxetine at 10 mg every other morning after citalopram is completely discontinued or at a very low dose 1
• Fluoxetine's very long half-life (4-6 days for the active metabolite) makes it less likely to cause withdrawal symptoms when eventually discontinued 1
• Increase fluoxetine gradually as needed up to 20 mg every morning 1

Monitoring for Side Effects

• Monitor for activation, nervousness, insomnia, and gastrointestinal disturbances 1
• Avoid starting fluoxetine at too high a dose, which may increase side effects 1

Monitoring During Transition

Follow-Up Schedule

• Schedule more frequent follow-up appointments during the tapering and switching period 1
• Follow up at least monthly during the taper, and more frequent contact may be needed during difficult phases 2
• Monitor for withdrawal symptoms, mood changes, and suicidal ideation 2
• Assess for return of original symptoms (depression/anxiety) and emergence of withdrawal symptoms 1

Common Pitfalls to Avoid

• Do not mistake withdrawal symptoms for relapse into depression, which may lead to unnecessary treatment changes 3
• Do not taper too quickly—standard 2-4 week tapers show minimal benefits over abrupt discontinuation and are often not tolerated 4
• Pauses in the taper are acceptable and often necessary when withdrawal symptoms emerge 2

Special Considerations

Why Fluoxetine is Advantageous for Switching

• Fluoxetine's extended half-life provides a "self-tapering" effect that minimizes withdrawal risk when eventually discontinued 1, 3
• This makes fluoxetine particularly useful as a destination SSRI when switching from shorter half-life agents like citalopram 3

Patient Education

• Educate patients that withdrawal symptoms are usually transient and not dangerous 3
• Reassure patients that mild symptoms can often be managed with simple reassurance 3
• Advise patients to report any concerning symptoms promptly rather than stopping medications abruptly 1