title: Intractable epistaxis associated with topiramate administration.
abstract: OBJECTIVE
  To report a case of a patient who experienced serious, intractable epistaxis warranting emergency department (ED) visits and hospital admission after initiation of topiramate therapy.
  
  
  METHODS
  A 61-year-old woman with significant cardiovascular disease was started on topiramate 25 mg daily for lower extremity neuropathy. After 7 days of treatment, she began to experience severe, intractable epistaxis that lasted 8 days, warranting an ED visit. The epistaxis resolved 1 week after topiramate discontinuation. Topiramate was restarted 3 months later, and the patient again developed intractable epistaxis. After 2 days of epistaxis, she returned to the ED with significant anginal pain and was admitted to the hospital, where she received 2 units of packed red blood cells. One week after stopping topiramate, the epistaxis stopped. At the time of writing, she had exhibited no epistaxis for 6 months. According to the Naranjo probability scale, topiramate was the probable cause of epistaxis.
  
  
  CONCLUSIONS
  Topiramate is a neuromodulatory compound approved for management of migraines, as well as partial and generalized tonic-clonic seizures. Over the past decade, its use has expanded to include many other neuropathic conditions. Currently, epistaxis has been reported in only 1-4% of patients receiving topiramate in clinical trials; however, these data were derived from a young study population. Like topiramate, calcium-channel blockers (CCBs) modulate voltage-gated L type calcium ion channels. These specific channels are located on vascular smooth muscle and non-contractile tissues such as platelets. Due to their possible antiplatelet effects, CCBs have been associated with an increased risk of hemorrhage, epistaxis, and prolonged bleeding time. The same may hold true for topiramate.
  
  
  CONCLUSIONS
  Topiramate, particularly in combination with antiplatelet medications, may be associated with severe, intractable epistaxis. Intractable epistaxis should be added to the list of potentially serious adverse reactions that are monitored when topiramate is administered.
authors.affiliation: Department of Clinical Pharmacy, Schools of Pharmacy and Medicine, University of Colorado Health Sciences Center, Denver, 80262, USA. robert.page@uchsc.edu
authors.forename: Robert L
authors.initials: RL
authors.lastname: Page
authors.forename: Jacquelyn L
authors.initials: JL
authors.lastname: Bainbridge
mesh_terms: D003929:Diabetic Neuropathies / Q000188:drug therapy*; D004844:Epistaxis / Q000139:chemically induced*; D005260:Female; D005632:Fructose / Q000009:adverse effects / Q000031:analogs & derivatives*; D006801:Humans; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy*; D000077236:Topiramate
chemical_list: D000077236:Topiramate; D005632:Fructose