Sodium oxybate demonstrates long-term efficacy for the treatment of cataplexy in patients with narcolepsy

Background and purpose: This study was conducted to demonstrate the long-term efficacy of sodium oxybate for the long-term treatment of cataplexy in patients with narcolepsy. Patients and methods: Fifty-five (55) narcoleptic patients with cataplexy who had received continuous treatment with sodium oxybate for 7-44 months (mean 21 months) were enrolled in a double-blind treatment withdrawal paradigm. A 2-week single-blind sodium oxybate treatment phase established a baseline for the weekly occurrence of cataplexy. This was followed by a 2-week double-blind phase in which patients were randomized to receive unchanged drug therapy or placebo. Patients recorded the incidence of cataplexy attacks and adverse events in daily diaries. Results: During the 2-week double-blind phase, the abrupt cessation of sodium oxybate therapy in the placebo patients resulted in a significant increase in the number of cataplexy attacks (median = 21; P < 0.001) compared to patients who remained on sodium oxybate (median = 0). Cataplexy attacks returned gradually with placebo patients reporting a median of 4.2 and 11.7 cataplexy attacks during the first and second weeks, respectively. There were no symptoms of frank withdrawal. Conclusions: This controlled trial provides evidence supporting the long-term efficacy of sodium oxybate for the treatment of cataplexy. In contrast with antidepressant drug therapy, there is no evidence of rebound cataplexy upon abrupt discontinuation of treatment. (C) 2004 Elsevier B.V. All rights reserved.