Open-label memantine in fragile X syndrome

J Autism Dev Disord. 2009 Dec;39(12):1629-35. doi: 10.1007/s10803-009-0807-3. Epub 2009 Jul 16.


Glutamatergic dysfunction is implicated in the pathophysiology of fragile X syndrome (FXS). The purpose of this pilot study was to examine the effectiveness and tolerability of memantine for a number of target symptoms associated with FXS. Medical records describing open-label treatment with memantine in 6 patients with FXS and a comorbid diagnosis of PDD were reviewed. Six patients received memantine over a mean 34.7 weeks of treatment. Four of 6 (67%) patients showed global clinical benefit on ratings with the CGI-I. Symptom specific rating scales, however, showed no statistically significant improvement. Two patient developed treatment-limiting irritability on memantine. Memantine was modestly effective in several patients with FXS. Further systematic study is warranted.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Child
  • Child Development Disorders, Pervasive / complications
  • Child Development Disorders, Pervasive / drug therapy*
  • Excitatory Amino Acid Antagonists / adverse effects
  • Excitatory Amino Acid Antagonists / therapeutic use*
  • Fragile X Syndrome / complications
  • Fragile X Syndrome / drug therapy*
  • Humans
  • Male
  • Memantine / adverse effects
  • Memantine / therapeutic use*
  • Pilot Projects
  • Psychiatric Status Rating Scales
  • Treatment Outcome
  • Young Adult


  • Excitatory Amino Acid Antagonists
  • Memantine