title: Dalfampridine may activate latent trigeminal neuralgia in patients with multiple sclerosis.
abstract: OBJECTIVE
  To determine the effect of dalfampridine (4-aminopyridine), a broad-spectrum, voltage-dependent potassium channel blocker, on patients with trigeminal nerve dysfunction due to multiple sclerosis (MS).
  
  
  METHODS
  We reviewed histories of 71 patients in our clinic with clinically definite MS who were treated with dalfampridine for at least 2 to 3 months. Of the 71 patients, 5 had a history of either trigeminal neuralgia or altered facial sensation.
  
  
  RESULTS
  Of these 5 patients, 3 with preexisting trigeminal neuralgia had a marked worsening of facial pain in close proximity to starting dalfampridine. One patient with altered facial sensation developed trigeminal pain after being on dalfampridine for 18 months. Pain in this individual rapidly subsided when dalfampridine was discontinued. Pain in the worsened 3 patients persisted, became more refractory to previously effective medications, and in one instance required trigeminal surgery for pain control.
  
  
  CONCLUSIONS
  Dalfampridine should be used with caution in persons with trigeminal neuralgia due to MS.
  
  
  METHODS
  This study provides Class IV evidence that treatment with dalfampridine may precipitate or exacerbate preexisting trigeminal neuralgia.
authors.affiliation: From the MS Treatment and Research Center, Minneapolis Clinic of Neurology, Golden Valley, MN. birnb001@umn.edu.
authors.forename: Gary
authors.initials: G
authors.lastname: Birnbaum
authors.affiliation: From the MS Treatment and Research Center, Minneapolis Clinic of Neurology, Golden Valley, MN.
authors.forename: Jane
authors.initials: J
authors.lastname: Iverson
mesh_terms: D015761:4-Aminopyridine / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications / Q000188:drug therapy*; D026902:Potassium Channel Blockers; D014277:Trigeminal Neuralgia / Q000139:chemically induced* / Q000209:etiology
chemical_list: D026902:Potassium Channel Blockers; D015761:4-Aminopyridine