Excessive Daytime Sleepiness (EDS)
Daytime sleepiness significantly decreased, as assessed by the Epworth Sleepiness Scale (ESS)[1][2]
Trial 3: From an 8-week, multicenter, randomized, double-blind, placebo-controlled, parallel-arm trial of narcolepsy patients (N=228) with moderate to severe EDS and cataplexy symptoms. Antidepressants were withdrawn prior to randomization, and stimulants were continued throughout the study at stable doses.
- A 37% reduction in ESS score seen with 9 g/night
- Patients taking XYREM® had scores closer to the normal range at end point
- Improvements in ESS scores demonstrated in a dose-dependent manner
- 78% of patients were being treated with CNS stimulants
- 41% of patients in the study were maintained on modafinil
The ESS is a subjective patient questionnaire that evaluates the extent of daytime sleepiness in everyday situations.
Scale: 0-8 normal, 9-12 mild, 13-16 moderate, ≥17 severe
Daytime wakefulness significantly increased, as assessed by the Maintenance of Wakefulness Test (MWT)[1][2]
Trial 4: From an 8-week, double-dummy trial that assessed 222 narcolepsy patients with moderate to severe symptoms. The patients enrolled in the study were randomized to 1 of 4 treatment groups: placebo, XYREM, modafinil, and XYREM plus modafinil. Patients were randomized to receive XYREM 6 g/night for 4 weeks and then 9 g/night for 4 weeks or placebo. The primary efficacy measure was objective change in EDS, as measured by MWT.
- The MWT is an objective measurement of latency to sleep onset (in minutes) following nocturnal polysomnography
- Higher scores indicate greater wakefulness
- XYREM and XYREM plus modafinil both provided significant improvements beyond baseline modafinil treatment when compared to placebo
- In this trial, patients had to be taking modafinil for 1 month and at stable doses of 200, 400, or 600 mg daily prior to randomization
- This trial was not designed to compare the effects of XYREM to modafinil, because patients receiving modafinil were not titrated to a maximally effective dose
The effective dose range of XYREM is 6 to 9 g/night
References:
- ^ The XYREM® International Study Group. A double-blind, placebo-controlled study demonstrates sodium oxybate is effective for the treatment of excessive daytime sleepiness in narcolepsy. J Clin Sleep Med. 2005;1:391–397.
- ^ XYREM® (sodium oxybate) [prescribing information]. Palo Alto, Calif: Jazz Pharmaceuticals; 2005.

