title: An analysis of the "carry-over effect" following successful short-term treatment of transformed migraine with divalproex sodium.
abstract: OBJECTIVE
  To determine whether successful short-term prophylactic treatment of transformed migraine may be followed by a continued respite from headaches once the treatment has been discontinued ("carry-over effect").
  
  
  BACKGROUND
  The optimal duration of prophylactic treatment for pervasive headache and for migraine, in particular, is unknown.
  
  
  METHODS
  We prospectively evaluated a series of patients with transformed migraine, all of whom were managed according to a uniform treatment protocol involving prophylactic therapy with divalproex sodium for a period not exceeding 12 weeks. All patients reporting a positive treatment response were followed for at least 2 months after the discontinuation of divalproex sodium, and the incidence of the carry-over effect in that group was assessed.
  
  
  RESULTS
  A short-term carry-over effect occurred in 12 (60%) of 20 patients, but more sustained relief occurred in only 8 (40%).
  
  
  CONCLUSIONS
  The successful short-term treatment of transformed migraine with divalproex sodium will often produce a short-term carry-over effect, but this response will be sustained only in a minority of patients.
authors.affiliation: University of South Alabama Headache Center, Mobile, Alabama 36617, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Rothrock
authors.forename: J E
authors.initials: JE
authors.lastname: Mendizabal
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000517:prevention & control*; D011446:Prospective Studies; D012008:Recurrence; D013997:Time Factors; D016896:Treatment Outcome; D014635:Valproic Acid / Q000494:pharmacology* / Q000627:therapeutic use*
chemical_list: D014635:Valproic Acid