Neurologic Deficits Following Oral Misuse of the Nasal Decongestant Propylhexedrine.

Introduction: Propylhexedrine is an over-the-counter nasal decongestant used recreationally for amphetamine-like effects. Prior reports have associated intravenous misuse with brainstem dysfunction and diplopia. This is a case of propylhexedrine ingestion resulting in neurological impairment with associated MRI findings.

Case report: A 21-year-old man presented with neurologic symptoms after ingesting propylhexedrine extracted from a 250 mg nasal inhaler into a lemon juice solution following recommendations from an online forum. He also followed recommendations to simultaneously ingest 1 g L-arginine to theoretically mitigate the risk of vasoconstriction. He developed flushing and euphoria before falling asleep. He awoke 12 h later with dizziness, intractable vomiting, diplopia, ataxia, dysmetria, and spontaneous horizontal nystagmus. Magnetic resonance imaging (MRI) revealed T2 enhancement concerning for vasogenic edema of the right posterior limbs of the internal capsule extending into the midbrain, cerebellar peduncles, and cerebellar white matter. Workup for primary vascular or autoimmune etiologies was unrevealing. Expanded drug testing was positive for mitragynine and THC. Blood analyzed via liquid chromatography quadrupole time-of-flight mass spectrometry was positive for propylhexedrine. On hospital day 6, the patient was discharged to physical rehabilitation with unresolved dysmetria and ataxia.

Discussion: Recreational oral misuse of propylhexedrine may be associated with neurologic injury. MRI findings in this case demonstrated vasogenic edema suggesting vasospasm as a possible etiology. Serum testing confirmed the presence of propylhexedrine. Although testing was also positive for mitragynine and THC, these have not been associated with similar neurologic deficits or MRI findings.