Herbal medicinal products or preparations for neuropathic pain

• Published in: Cochrane database of systematic reviews 2019-04, Vol.4 (4), p.CD010528-CD010528
• Main Authors: Boyd, Adele, Bleakley, Chris, Hurley, Deirdre A, Gill, Chris, Hannon-Fletcher, Mary, Bell, Pamela, McDonough, Suzanne
• Format: Article
• Language: English
• Subjects: Adult; Analgesics - therapeutic use; Chronic Pain - drug therapy; Complementary & alternative medicine; Humans; Neuralgia - drug therapy; Neurology; Phytotherapy; Plant Extracts - therapeutic use; Randomized Controlled Trials as Topic; Treatment Outcome
• ISSN: 1469-493X
• DOI: 10.1002/14651858.CD010528.pub4

Neuropathic pain is a consequence of damage to the central nervous system (CNS), for example, cerebrovascular accident, multiple sclerosis or spinal cord injury, or peripheral nervous system (PNS), for example, painful diabetic neuropathy (PDN), postherpetic neuralgia (PHN), or surgery. Evidence suggests that people suffering from neuropathic pain are likely to seek alternative modes of pain relief such as herbal medicinal products due to adverse events brought about by current pharmacological agents used to treat neuropathic pain. This review includes studies in which participants were treated with herbal medicinal products (topically or ingested) who had experienced neuropathic pain for at least three months. To assess the analgesic efficacy and effectiveness of herbal medicinal products or preparations for neuropathic pain, and the adverse events associated with their use. We searched CENTRAL and the Cochrane Database of Systematic Reviews, MEDLINE, Embase, CINAHL and AMED to March 2018. We identified additional studies from the reference lists of the retrieved papers. We also searched trials registries for ongoing trials and we contacted experts in the field for relevant data in terms of published, unpublished or ongoing studies. We included randomised controlled trials (including cross-over designs) of double-blind design, assessing efficacy of herbal treatments for neuropathic pain compared to placebo, no intervention or any other active comparator. Participants were 18 years and above and had been suffering from one or more neuropathic pain conditions, for three months or more.We applied no restrictions to language or gender. We excluded studies monitoring effects of isolated, single chemicals derived from the plant or synthetic chemicals based on constituents of the plant, if they were not administered at a concentration naturally present within the plant.We excluded studies monitoring the effects of traditional Asian medicine and Cannabinoids as well as studies looking at headache or migraine as these treatments and conditions are addressed in distinct reviews. We used standard methodological procedures expected by Cochrane. Two review authors independently considered trials for inclusion, assessed risk of bias, and extracted data. We calculated the risk ratio (RR) and number needed to treat for an additional beneficial outcome (NNTB). The primary outcomes were participant-reported pain relief of 30%, or 50%, or greater, and participant-reported g