1269 Off-Label Use of Solriamfetol In Idiopathic Hypersomnia

Abstract

Introduction Solriamfetol is a new daily dopamine and norepinephrine reuptake inhibitor indicated for improving daytime wakefulness in adults with obstructive sleep apnea (OSA) and narcolepsy. It was FDA-approved on 3/20/2019. In this report, we present a patient with refractory idiopathic hypersomnia (IHS) who benefitted from off-label use of solriamfetol at a private sleep center. Report of Case A 37-year-old non-obese female previously diagnosed with IHS vs narcolepsy, presented in 2015 with excessive daytime sleepiness since her mid-teens. She also had a history of periodic limb movement (PLM) and anxiety and trialed clonazepam, which caused daytime hangover effects. At her previous office, she began sodium oxybate but had psychiatric side effects, and was thus started on methylphenidate. Modafinil was added due to build-up of tolerance. Three separate polysomnographies (PSG) over 9 years revealed similar findings of mild snoring without OSA, PLM with variable arousals. Multiple sleep latency testing (MSLT) showed very rapid sleep onset <4 min and no sleep-onset REM periods. The patient never had cataplexy but occasional hypnogogic hallucinations and sleep paralysis. All studies to-date suggested IHS, less likely narcolepsy without cataplexy, and at her initial visit, the patient trialed armodafinil instead of modafinil, and methylphenidate was weaned down. When seen again in 2017, the patient reported persistent daytime sleepiness on methylphenidate and modafinil (PSG-MSLT showed sleep latencies ~3.5 min on 5/5 nap opportunities), without cataplexy. When seen 9/2019, patient continued to have daytime sleepiness and fatigue. She was then weaned off methylphenidate and modafinil, and started on solriamfetol. Since then, she has been doing well solely on solriamfetol 75mg BID. Conclusion Off-label use of solriamfetol for IHS has been demonstrated to be effective in a treatment-resistant patient at a private sleep center. More data and further discussion in support of its off-label use are warranted for this patient population.