Should a patient on escitalopram (Lexapro) stop the SSRI before undergoing a Multiple Sleep Latency Test (MSLT)?

Should Lexapro Be Stopped Before MSLT?

Yes, escitalopram (Lexapro) must be discontinued at least 2 weeks before the Multiple Sleep Latency Test (MSLT) to ensure valid results. 1

Why SSRIs Like Lexapro Must Be Stopped

Antidepressants that suppress REM sleep—including all SSRIs like escitalopram—directly alter MSLT outcomes and can mask narcolepsy. 1 The evidence is compelling:

• Patients who discontinued REM-suppressing antidepressants (REMS-ADs) before MSLT were 12 times more likely to demonstrate ≥2 sleep-onset REM periods (SOREMPs) compared to those who remained on these medications (odds ratio: 12.20; 95% CI: 1.60-92.94). 1

• Patients who tapered off REMS-ADs had significantly shorter mean sleep latencies (8.77 vs 10.21 minutes, P = 0.009) and more than double the odds of meeting diagnostic criteria for narcolepsy (≥2 SOREMPs) compared to those not taking antidepressants at all (odds ratio: 2.22; 95% CI: 1.23-3.98). 1

• The American Geriatrics Society explicitly recommends that sedating medications—which include antidepressants with sedating properties—should be discontinued before MSLT. 2

Specific Taper Timeline for Lexapro

Discontinue escitalopram 2 weeks prior to MSLT. 1 This is the standard protocol used at major sleep centers:

• Most antidepressants require a 2-week washout period 1
• Fluoxetine is the exception, requiring 6 weeks due to its long half-life 1
• Escitalopram has a half-life of approximately 27-32 hours, making 2 weeks adequate for complete clearance

Additional Critical Pre-MSLT Requirements

Beyond stopping Lexapro, several other steps are mandatory:

Discontinue Other Interfering Medications

All stimulants (amphetamines, methylphenidate, modafinil) and sedating agents (benzodiazepines, hypnotics, antihistamines) must also be stopped before MSLT. 2, 3

Document Adequate Sleep for 7-14 Days

Use wrist actigraphy for 7-14 days before MSLT to objectively verify adequate sleep duration and resolve chronic sleep debt. 2, 4, 3 This is critical because:

• Chronic sleep deprivation is the most common cause of false-positive MSLT results 3, 5
• Sleep logs overestimate sleep time by approximately 1.5 hours per night; only actigraphy shows a significant relationship between nighttime sleep duration and MSLT outcomes 4, 3
• Adults require ≥6 hours total sleep time on the overnight polysomnography immediately before MSLT 4

Verify Compliance with Urine Drug Screen

Perform urinary drug screening following overnight polysomnography, as 16% of patients test positive for undisclosed substances that invalidate MSLT interpretation. 6 Patients frequently do not self-report medication use. 6

Common Pitfall: Inadequate Washout Period

If escitalopram is not discontinued or the washout period is insufficient, the MSLT interpretation must include a statement that REM-suppressing medication may have affected the results and potentially masked narcolepsy. 1

• In one study, 30% of patients remained on REMS-ADs during MSLT, leading to potentially missed diagnoses 1
• Five patients in a case series had false-positive results from accumulated sleep debt alone, which would have led to inappropriate psychostimulant prescriptions 5

Clinical Context

The MSLT should only proceed after:

1. Lexapro tapered off for ≥2 weeks 1
2. Actigraphy confirms 7-14 days of adequate sleep (≥6 hours/night for adults) 2, 4, 3
3. Overnight polysomnography documents ≥6 hours total sleep time 4
4. All other REM-suppressing and alertness-altering medications discontinued 2, 3
5. Urine drug screen performed 6

Failure to meet these conditions will compromise diagnostic accuracy and may result in misdiagnosis of narcolepsy or idiopathic hypersomnia. 1, 6