Ondansetron or placebo in the augmentation of fluvoxamine response over 8 weeks in obsessive–compulsive disorder

Abstract

The aim of this study was to investigate the efficacy and safety of ondansetron as an augmentative agent to fluvoxamine in the treatment of patients with obsessive-compulsive disorder (OCD). Forty-six men and women, aged 18-60 years, who fulfilled the diagnostic criteria of OCD on the basis of the DSM-IV-TR and had a Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score of at least 21 were recruited into the study. The patients randomly received either ondansetron (8 mg/day) or placebo for 8 weeks. All patients received fluvoxamine (100 mg/day) for the first 4 weeks, followed by 200 mg/day for the rest of the trial. The patients were assessed using the Y-BOCS and the adverse event checklists at baseline, and the second, fourth, sixth, and eighth week. Forty-four patients completed the study. The Y-BOCS total score as well as the Y-BOCS obsession subscale score and compulsion subscale score showed significantly greater reduction in the ondansetron group than in the placebo group. There was no significant difference in adverse events between the two groups. In this 8-week double-blind randomized-controlled trial, ondansetron showed significant beneficial effect as an augmentative agent with fluvoxamine in patients with moderate to severe OCD and it was generally well tolerated.

Ondansetron Augmentation of Serotonin Reuptake Inhibitors as a Treatment Strategy in Obsessive-Compulsive Disorder

“…In brief, ondansetron was effective in the uncontrolled as well as in the placebo-controlled trials. In contrast with usual findings in psychopharmacology studies, ondansetron augmentation was more strikingly effective in the RCTs 19,20 than in the uncontrolled studies. 17,18 There are 2 possible explanations.…”

“…Soltani et al 19 found the greatest separation between ondansetron and placebo at weeks 2 and 8; Heidari et al 20 found the greatest separation at weeks 6-8.…”

“…One is that patients in the uncontrolled studies 17,18 had a documented history of poor response to ongoing and/or previous anti-OCD medications; in contrast, previous medication history was not reported in the controlled trials, 19,20 and patients were off all psychotropic medications for at least the previous 6 weeks. The other is that ondansetron was dosed at higher levels in the RCTs 19,20 as compared with the uncontrolled trials. The issue of inadequate ondansetron dose versus diminished ondansetron efficacy in previously inadequately responding patients therefore needs clarification.…”

“…As with the only other RCT, 19 this study 20 was unusual in that patients were at least 6 weeks free of all psychotropic drugs at baseline. These authors 20 also provided no details of previous treatments (if any) and response thereto.…”

Evidence-Based Treatments in Treatment-Naïve and Treatment-Resistant Pediatric Obsessive-Compulsive Disorder

“…The other strategy is augmenting an SSRI with a serotonin 5-HT 3 receptor antagonist [77]. One double-blind RCT has shown the benefits of augmenting an SSRI with granisetron in adult OCD [78], and two doubleblind RCTs have shown the benefits of ondansetron in adult OCD [79,80]. These treatments are clearly to be used by experts in true treatment-refractory OCD.…”