title: Ondansetron augmentation in patients with obsessive-compulsive disorder who are inadequate responders to serotonin reuptake inhibitors: improvement with treatment and worsening following discontinuation.
abstract: OBJECTIVE
  The aim of this study was to evaluate low-dose ondansetron as an augmentation strategy in patients with obsessive-compulsive disorder (OCD) who do not adequately respond to serotonin reuptake inhibits (SRIs).
  
  
  METHODS
  Twenty-one OCD patients who had not responded adequately to an SRI received 12 weeks of single-blind ondansetron augmentation initiated at 0.25mg BID for 2 weeks, and titrated to 0.5mg BID for an additional 10 weeks. Patients were rated every two weeks using the Yale-Brown Obsessive Compulsive Scale (YBOCS) and Clinical Global Impressions Scale (CGI). Treatment response was defined as an additional 25% reduction in YBOCS score from the score at the initiation of ondansetron augmentation, an end of treatment YBOCS score of ≤ 24 and a CGI-Improvement (CGI-I) score of ≤ 2. Upon completion of treatment course patients were followed for 4 weeks.
  
  
  RESULTS
  At week 12, twelve of the 21 (57%) patients were responders. The average reduction in the YBOCS score for the overall group was 27.2%. Responders had an average 44% YBOCS score reduction and 76.9% CGI-I reduction. After discontinuation of ondansetron the YBOCS worsened an average of 15.5% in the entire sample and 38.3% in the responder subsample. No clinically meaningful side effects were reported.
  
  
  CONCLUSIONS
  OCD patients who do not adequately respond to an SRI may benefit from augmentation with a low-dose of ondansetron. This may provide an alternative approach to augmentation with atypical antipsychotic agents, with a more favorable safety profile.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, UC Davis Health System Sacramento, CA, USA; Department of Psychiatry, University of Florence, Italy; Department of Psychiatry, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, USA. Electronic address: stefano.pallanti@ucdmc.ucdavis.edu.
authors.forename: Stefano
authors.initials: S
authors.lastname: Pallanti
authors.affiliation: Department of Psychiatry and Behavioral Sciences, UC Davis Health System Sacramento, CA, USA; Department of Psychiatry, University of Florence, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Bernardi
authors.affiliation: Department of Psychiatry, University of Florence, Italy.
authors.forename: Sarah
authors.initials: S
authors.lastname: Antonini
authors.affiliation: Transcept Pharmaceuticals, Inc., USA.
authors.forename: Nikhilesh
authors.initials: N
authors.lastname: Singh
authors.affiliation: Department of Psychiatry and Behavioral Sciences, UC Davis Health System Sacramento, CA, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Hollander
mesh_terms: D000328:Adult; D000368:Aged; D014151:Anti-Anxiety Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000188:drug therapy*; D017294:Ondansetron / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D011569:Psychiatric Status Rating Scales; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use*; D016037:Single-Blind Method; D013997:Time Factors; D016896:Treatment Outcome; D044465:White People; D055815:Young Adult
chemical_list: D014151:Anti-Anxiety Agents; D017294:Ondansetron; D017367:Selective Serotonin Reuptake Inhibitors
keywords: 5-HT3; Augmentation; Low-dose ondansetron; OCD