METHODS: We systematically searched scientific repositories for trials investigating conventional oral, and/or parenteral, pharmaceutical antineuropathic treatments in patients with IBS. We summarized key participant characteristics, outcomes related to pain (primary outcome), and selected secondary outcomes.
RESULTS: We included 13 studies (n = 629 participants): six investigated amitriptyline, three duloxetine, three pregabalin, and one gabapentin. There was considerable methodological and statistical heterogeneity, so we performed a narrative synthesis and limited meta-analysis. Amitriptyline was most extensively studied, though only in diarrhea-predominant patients. In individual trials, amitriptyline, pregabalin and gabapentin generally appeared beneficial for pain outcomes. While duloxetine studies tended to report improvements in pain, all were un-controlled trials with high risk of bias. Meta-analysis of three studies (n = 278) yielded a pooled relative-risk of 0.50 (95%CI 0.38-0.66) for not improving with anti-neuropathic agent vs control. We did not identify any eligible studies investigating the role of parenteral anti-neuropathics.
UNASSIGNED: Anti-neuropathic analgesics may improve pain in IBS, and deserve further, high-quality investigation, potentially considering parenteral administration and agents with minimal gastrointestinal motility effects. Investigation of amitriptyline\'s efficacy in non-diarrhea-predominant subtypes is currently lacking, and we recommend particular caution for its use in IBS-C.