Ondansetron augmentation in patients with obsessive-compulsive disorder who are inadequate responders to serotonin reuptake inhibitors: Improvement with treatment and worsening following discontinuation

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

“…Additionally, in the latter report 18 there were inconsistencies between the abstract and text and also within the text itself. Also, surprisingly, although the study was uncontrolled, in one section the authors 18 referred to experimental and control groups.…”

“…Other concerns are briefly described. Two of the open trials 15,18 reported worsening of OCD symptoms after discontinuation of ondansetron; however, neither of the RCTs 19,20 conducted posttreatment follow-up assessments under blinded conditions, and so the duration of persistence of benefits and the need for continuation therapy remain unresolved. In particular, the safety and efficacy of ondansetron in the long term require study if ondansetron is to be considered as a serious alternative to SRI augmentation with atypical antipsychotic drugs in poor responders.…”

“…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. 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.…”

“…17,18 There are 2 possible explanations. 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.…”

“…In another study of low-dose ondansetron described by the same authors, 18 the sample comprised 21 adults with OCD, all of whom had responded inadequately to an SRI. Ondansetron augmentation was begun at 0.25 mg twice daily for 2 weeks and was up-titrated to 0.5 mg twice daily for 10 further weeks.…”