Cataplexy-Like Episodes Following Suvorexant Use in a Non-Narcoleptic Patient: A Brief Report

Dual orexin receptor antagonists (DORAs) such as suvorexant are effective treatments for insomnia but are associated with rapid eye movement (REM) sleep-related adverse effects. While sleep paralysis and hypnagogic hallucinations are recognised, cataplexy is not typically reported. We describe a 39-year-old male US Navy Veteran with chronic pain, long-standing insomnia and anxiety who developed recurrent, emotionally triggered episodes of bilateral ptosis, slurred speech, unsteadiness and subjective "euphoric" sensations shortly after initiating suvorexant. Neurologic evaluation, electroencephalography, electromyography and brain imaging were unrevealing. Multiple sleep latency testing demonstrated normal mean sleep latency without sleep-onset REM periods, excluding narcolepsy. Polysomnography revealed mild obstructive sleep apnea. Symptoms diminished substantially following suvorexant discontinuation and multimodal treatment including cognitive behavioural therapy for insomnia, escitalopram and continuous positive airway pressure therapy, though mild residual symptoms persisted. This case suggests that suvorexant may provoke cataplexy-like phenomena via REM-intrusion mechanisms in susceptible individuals. Clinicians should monitor for atypical motor or speech symptoms in patients prescribed DORAs, particularly those with psychiatric comorbidity or sleep fragmentation.