In the last five years, several systematic reviews with and without meta-analyses and overviews of systematic reviews of randomised controlled trials with cannabis-based medicines (CBMs) for chronic pain in general and for some pain conditions (e.g. neuropathic pain; rheumatic diseases) have been published. There are striking differences in the results and the conclusions of these reviews on the efficacy, tolerability and safety of CBMs for pain management and of its quality of evidence. Some reviews stated that CBMs are effective for pain management and some stated that they were not. The same discrepancies can be found with regards to tolerability and safety. In my lecture I will point out some reasons for the discrepancies, e.g. inclusion and exclusion criteria; the search of„grey literature“ ; the outcomes analysed; the statistical methods used; dealing with missing data ; different methods of balancing benefits and harms; criteria of evidence use.: I will demonstrate that methodological flaws of some systematic reviews led to an overestimation of the efficacy and an underestimation of the safety of CBMs for pain management.
Häuser W, Petzke F, Fitzcharles MA. Efficacy, tolerability and safety of cannabis-based medicines for chronic pain management - An overview of systematic reviews. Eur J Pain 2018;22:455-470.