Full Prescribing Information Important Safety Information Medication Guide


XYREM Significantly Reduced Weekly Cataplexy Attacks

Two randomized, placebo-controlled trials demonstrated the efficacy of XYREM for the treatment of cataplexy in narcolepsy.

Trial 1 was a 4-week, double-blind, placebo-controlled trial of 136 narcolepsy patients with moderate-to-severe cataplexy (median of 21 attacks/week). At the end of week 4, a 69% reduction in attacks was seen with XYREM 9 g/night (P<0.005 vs placebo), and a 49% reduction was seen with XYREM 6 g/night (P<0.05 vs placebo). The greatest reduction was observed within 2 weeks.

However, additional improvements continued throughout the entire 4-week trial[1]. In XYREM clinical trials, ≈80% of patients maintained concomitant stimulant use[2].

  • Due to the rapid onset of its CNS depressant effects, XYREM should only be ingested at bedtime, and while in bed. For at least 6 hours after taking XYREM, patients must not engage in hazardous occupations or activities requiring complete mental alertness or motor coordination, such as operating machinery, driving a motor vehicle, or flying an airplane.
  • When patients first start taking XYREM, they should use extreme care while performing any task that could be dangerous or requires full mental alertness until they know whether XYREM will have some carryover effect on them the next day.
  • XYREM can cause serious adverse events, including confusion, other neuropsychiatric adverse events (psychosis, paranoia, hallucination, and agitation), loss of consciousness, urinary incontinence, and sleepwalking. Patients should call their doctor if they experience any of these events.

The effective dose range of XYREM is 6 to 9 g/night

Gradual Return of Cataplexy Upon XYREM Discontinuation

Trial 2 documented the continued efficacy of XYREM after long-term use. Patients in this trial had been receiving open-label XYREM for an average of 21 months prior to study enrollment. At the beginning of the trial, they were randomized in a double-blind fashion to continued XYREM use or to placebo[2]. At the end of the 2-week study period, those who continued XYREM experienced no median increase in the number of cataplexy attacks/week, while those in the placebo group experienced a gradual return of cataplexy[2].

It is important to note that, although cataplexy gradually returned in the placebo group, no rebound cataplexy was seen following abrupt discontinuation of XYREM[2].

In XYREM clinical trials, ≈80% of patients maintained concomitant stimulant use[2].

Gradual Return of Cataplexy

The reduction in cataplexy attacks was maintained after an average of 21 months of XYREM use[2][3].Patients who remained on XYREM showed no median increase in cataplexy attacks.

  • The emergence of depression when patients are treated with XYREM requires careful and immediate evaluation. Patients with a previous history of a depressive illness and/or suicide attempt should be monitored especially carefully for the emergence of depressive symptoms while taking XYREM.
  • Daily sodium intake should be considered in patients on salt-restricted diets or with heart failure, hypertension, or compromised renal function

To report an adverse event please call: 1-800-520-5568




  1. ^ The US XYREM® Multicenter Study Group. A randomized, double blind, placebo-controlled multicenter trial comparing the effects of three doses of orally administered sodium oxybate with placebo for the treatment of narcolepsy. Sleep. 2002;25:42–49.
  2. ^ XYREM® (sodium oxybate) [prescribing information]. Palo Alto, Calif: Jazz Pharmaceuticals, Inc.
  3. ^ The US XYREM® Multicenter Study Group. Sodium oxybate demonstrates long-term efficacy for the treatment of cataplexy in patients with narcolepsy. Sleep Med. 2004;5:119–123.
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