Benefits and risk of sodium oxybate in idiopathic hypersomnia versus narcolepsy type 1: a chart review

Abstract

Background: Few stimulants have been evaluated for the treatment of idiopathic hypersomnia (IH). Sodium oxybate (indicated in narcolepsy type 1, NT1) has not been tested in IH patients.

Objective: The aim of this study is to retrospectively evaluate the benefit/risk ratio of sodium oxybate in IH versus NT1 using a chart review.

Methods: We reviewed the files of 46 patients with IH (35.7 ± 12.6 years old, 78% women) and 47 patients with NT1 (44.1 ± 18 years old, 47% women) and evaluated the benefits of sodium oxybate using the Epworth sleepiness scale (ESS) and a four-point scale assessing the global benefit, sleep inertia, sleepiness, sleep duration, and sleep onset latency. The spontaneously reported side effects were collected.

Results: Sodium oxybate was prescribed at a lower dose in IH than in NT1 (4.3 ± 2.2 vs. 6.6 ± 2.8 g/night, p <0.0001) patients after having tried more (3.2 ± 1.4 vs. 2.2 ± 1, p <0.0001) stimulants, but it produced a similar ESS change (-3.5 ± 4.5 vs. -3.2 ± 4.2 points) in the IH and NT1 groups. Severe morning inertia was improved in 24/34 (71%) patients with IH. During the follow-up period (15.8 months in IH vs. 35 months in NT1 groups), 53% IH and 68% NT1 patients dropped out. The side effects were as frequent in the IH group as in the NT1 group (67% vs. 52%), but nausea (40% vs. 13%) and dizziness (34.3% vs. 4.3%) were more frequent in the IH group.

Conclusion: The benefit/risk ratio of sodium oxybate in IH- was similar to NT1-associated sleepiness, with additional benefits on severe morning inertia, despite using smaller doses in more refractory patients.

Keywords: Gamma-OH butyrate; Idiopathic hypersomnia; Narcolepsy type 1; Sleep inertia; Sleepiness; Sodium oxybate.