Can a cross-taper between Lexapro (escitalopram) and citalopram cause sleep paralysis?

Cross-Taper Between Lexapro and Citalopram: Sleep Paralysis Risk

A cross-taper between escitalopram (Lexapro) and citalopram is unlikely to cause sleep paralysis, as these medications are essentially the same drug—escitalopram is simply the active S-enantiomer of citalopram—making this transition one of the safest antidepressant switches possible. 1

Why This Switch Is Low-Risk

Pharmacologic similarity minimizes risk:

• Escitalopram is the therapeutically active S-isomer of citalopram, while R-citalopram (the other half of citalopram) is approximately 30-fold less potent at the serotonin transporter 1
• Both medications have the least effect on CYP450 isoenzymes compared with other SSRIs, resulting in lower propensity for drug interactions 2
• The similar half-lives (27-32 hours for escitalopram) support once-daily dosing and smooth transitions 1

Sleep Paralysis and SSRIs: The Evidence

Sleep paralysis as an SSRI side effect is extremely rare but documented:

• One case report describes sertraline-induced sleep paralysis that resolved upon medication discontinuation 3
• Paradoxically, escitalopram has been successfully used to treat recurrent isolated sleep paralysis in two documented cases, as it generally improves subjective sleep quality 4
• In clinical trials of escitalopram for depression and anxiety (n=5,133 for MDD; n=2,052 for GAD), escitalopram significantly improved sleep problems compared to placebo, other SSRIs, and SNRIs 5

Safe Cross-Taper Approach

When switching between citalopram and escitalopram, use a direct substitution or minimal overlap:

• Given their pharmacologic similarity, a conservative approach involves tapering citalopram over 1-2 weeks while simultaneously starting escitalopram at a low dose 2
• Monitor for symptoms especially in the first 24-48 hours after dosage changes, though serotonin syndrome risk is minimal with this specific combination 2
• The most common adverse events with escitalopram include nausea, insomnia, diarrhea, dry mouth, and somnolence—but not sleep paralysis 1

Important Caveats

Watch for discontinuation syndrome rather than sleep paralysis:

• Citalopram is a shorter-acting SSRI that can cause discontinuation syndrome characterized by dizziness, fatigue, insomnia, sensory disturbances, and anxiety if stopped abruptly 2
• Gradual dose reduction over days to weeks reduces the risk and severity of withdrawal complications 6

Monitor for cardiac effects instead:

• Citalopram may cause QT prolongation at daily doses exceeding 40 mg/d and should be avoided in patients with long QT syndrome 2
• Both citalopram and escitalopram have had maximum dose restrictions imposed by FDA and EMA due to QT concerns 2