Takeaway
A reduction in serum neurofilament heavy chain protein (NfH) is evident in patients with acute optic neuritis (ON) following 3 months of phenytoin treatment.
Why this matters
Both neurofilament light chain protein (NfL) and NfH have prognostic value in predicting worsening disability in multiple sclerosis over time; and in patients presenting with ON, elevated blood NfH levels in particular are associated with poor visual outcomes.
Phenytoin may have potential use as a therapeutic option in acute ON, improving visual outcomes for patients in this disease phase; however, further study is required for confirmation.