Cataplexy Without Treatment
Orexin loss lets strong emotions collapse muscle tone instantly.
- 15–25: Cataplexy episodes/week (untreated baseline)
- ~8%: Slow-wave sleep (fragmented, low)
- 10–14: Nighttime awakenings (per night)
- >90%: Orexin neuron loss (hypothalamic destruction)
Orexin deficiency
Autoimmune loss of orexin neurons destabilizes REM-wake boundaries.
Emotional triggers
Laughter, surprise, or anger can trigger sudden collapse.
Cataplexy is REM-atonia intruding directly into wakefulness.
Fragmented nights
Frequent awakenings prevent restorative deep sleep from building.
First Bedtime Dose
Sodium oxybate at bedtime rapidly induces deep sedation.
- 5–15: Onset of sedation (minutes)
- ~0.5–1: Elimination half-life (hours, short)
- GABA-B: Receptor mechanism (direct agonist)
- ~30–60: Peak plasma level (minutes post-dose)
Rapid absorption
Oral solution absorbs quickly when taken on an empty stomach.
GABA-B agonism
Drug binds GABA-B receptors, deepening sedation quickly.
Short half-life
Fast clearance means the first dose fades before morning.
Deep Sleep Enhancement
Sodium oxybate expands slow-wave sleep across the night.
- 18–24%: Slow-wave sleep (up from baseline)
- Increased: EEG delta power (slow-wave amplitude)
- 6–8: Nighttime awakenings (per night, falling)
- Improved: REM consolidation (less fragmented)
Slow-wave boost
Drug increases delta-wave EEG activity substantially.
Fewer arousals
Deeper sleep reduces microarousals and awakenings.
More slow-wave sleep tracks with fewer next-day cataplexy attacks.
Hormonal restoration
Slow-wave sleep also restores growth-hormone rhythms.
Second Dose, 2.5–4 Hours Later
A repeat dose maintains GABA-B effect through the night.
- 2.5–4: Redosing interval (hours after first dose)
- Extended: Plasma coverage (through early morning)
- Critical: Adherence importance (timing must be precise)
- Sustained: Sleep continuity (second half of night)
Why redose
Short half-life requires a second dose to sustain benefit.
Timing precision
Missed or late second doses weaken overnight control.
Patient burden
Waking to redose mid-sleep challenges long-term adherence.
Reduced Cataplexy Frequency
Consolidated sleep and steady dosing sharply cut cataplexy attacks.
- 1–4: Cataplexy episodes/week (with adherent dosing)
- 22–28%: Slow-wave sleep (near-normal levels)
- 2–4: Nighttime awakenings (per night)
- ~8–12: Weeks to full effect (titration period)
Sustained control
Weeks of adherent dosing yield stable cataplexy suppression.
Daytime benefit
Better nights reduce sleepiness and emotional triggering.
Adherence matters
Skipped doses quickly erode cataplexy control.
Consistent split-dosing is the strongest predictor of control.