woman narcolepsy

“What clinical effects were seen for cataplexy in adult narcolepsy?”

XYREM, at the 6 g and 9 g per night dosages, significantly decreased the frequency of cataplexy in adults.1

The results of the XYREM Trial N1 showed...

  • Dosages of 6 g and 9 g per night significantly reduced the frequency of cataplexy attacks compared with placebo at week 4.1
  • The greatest reduction at week 4 was seen with the 9 g per night dosage.1
  • The 3 g per night dosage had little effect.1
  • Dosages higher than 9 g per night have not been studied and should not ordinarily be administered.1


Reductions in Cataplexy at Week 41

Xyrem n1 clinical trial reductions in cataplexy graph

BL = Baseline

*P<0.05 vs placebo.

P<0.005 vs placebo.

Median change from baseline in attacks per week:

XYREM 6 g per night = -10

XYREM 9 g per night = -16

Placebo = -4

Trial N1 Study Description

Study Design1,3

  • Randomized, double-blind, placebo-controlled, parallel-group, multicenter trial
  • Compared effects of 3 dosages of orally administered XYREM (3 g, 6 g, and 9 g per night) with placebo

Patients Studied1,3

  • 136 adult narcolepsy patients with moderate to severe cataplexy

Baseline Characteristics1,3,4

  • Mean age: 43.1 years
  • Median number of weekly cataplexy attacks: 21
    • Range: 3 to 249 per week
  • On average, partial attacks (about 25 per week) were more frequent than complete attacks (about 9 per week)
    • Partial attack range: 0 to 228 per week
    • Complete attack range: 0 to 117 per week
  • 85% were taking concomitant stimulant medications


  • Evaluate and compare the efficacy and safety of 3 dosages of XYREM with placebo for the treatment of cataplexy in narcolepsy

Primary Efficacy Measure3

  • Change from baseline in number of weekly cataplexy attacks

Trial N1 Study Design Flowchart1,3,4

Xyrem efficacy in cataplexy n1 study design flowchart
  • Prior to baseline measures, subjects discontinued anticataplectic agents (eg, SSRIs and tricyclic antidepressants).
    • Gradually withdrawn over a period of up to 4 weeks from medications previously used to treat cataplexy symptoms, followed by a washout period of 5 days or 5 times the half-life of the discontinued anticataplectic medication, up to 28 days (whichever option was longer).
  • Each patient was randomized to receive 3 g, 6 g, or 9 g of XYREM or placebo per night for 4 weeks, with the total nightly dosage administered as 2 equal doses. XYREM was not titrated in this clinical trial.
  • Patients were allowed to continue the concomitant use of stimulant medications.

It is recommended that XYREM be titrated at weekly intervals, by adding 1.5 g per night, from 4.5 g to the effective dosage range of 6 g to 9 g per night.1


The American Academy of Sleep Medicine (AASM) recommends sodium oxybate as a standard of care for the treatment of cataplexy in narcolepsy.2