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

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.

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

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.

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.

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.