Medication Discontinuation Before MSLT
Clomipramine 50 mg should be discontinued at least 2 weeks before MSLT, and Adderall (mixed amphetamine salts) should be discontinued at least 2 weeks before MSLT.
Rationale for Discontinuation Timeline
Clomipramine (REM-Suppressing Antidepressant)
Clomipramine is a tricyclic antidepressant that significantly suppresses REM sleep and can profoundly affect MSLT results. Based on the FDA pharmacokinetic data, steady-state plasma levels are not achieved until 2-3 weeks after dosage changes due to the long elimination half-lives of both clomipramine (mean 32 hours, range 19-37 hours) and its active metabolite desmethylclomipramine (mean 69 hours, range 54-77 hours) 1.
The research evidence strongly supports this timeline: patients who discontinued REM-suppressing antidepressants (REMS-ADs) prior to MSLT were 12 times more likely to have ≥2 SOREMs (sleep-onset REM periods) compared to those who remained on these medications during testing 2. Additionally, they demonstrated:
- Shorter mean sleep latency (8.77 vs 10.21 minutes, p = 0.009)
- Higher odds of ≥2 SOREMs (OR: 2.22) compared to patients not taking REMS-ADs at all 2
At Mayo Clinic's protocol (which generated this evidence), all antidepressants are discontinued 2 weeks prior to MSLT 2. Given clomipramine's long half-life and the 2-3 week period needed to reach steady-state (or conversely, to clear), a minimum 2-week washout is appropriate for the 50 mg dose.
Adderall (Mixed Amphetamine Salts)
Amphetamines are potent stimulants that promote wakefulness and can significantly alter sleep architecture. A 2-week discontinuation period is recommended to ensure complete clearance and normalization of sleep patterns before testing.
While the provided evidence doesn't specify exact washout periods for stimulants before MSLT, the research demonstrates that stimulants affect sleep patterns 3 and can influence cognitive and physiological measures 4. The standard practice is to discontinue all REM-suppressing and wake-promoting medications at least 2 weeks before MSLT to avoid false-negative results.
Critical Clinical Considerations
Important caveat: If clomipramine cannot be safely discontinued due to severe OCD or depression, the MSLT results must include a statement that the medication may have suppressed REM sleep and artificially prolonged sleep latency, potentially masking narcolepsy 2. The test interpretation becomes limited and may require repeat testing after medication discontinuation if clinically feasible.
For both medications: Abrupt discontinuation should be avoided. Clomipramine requires gradual tapering to prevent withdrawal symptoms 1. Coordinate with the prescribing psychiatrist to ensure safe discontinuation, particularly for clomipramine given its use in OCD treatment.