Pain intensity of chronic non-cancer patients was reduced by cannabinoids consumption , but effect sizes were small .
Efficacy for neuropathic and non-neuropathic pain was similar
There is growing interest in using cannabinoids for chronic pain .
We performed a systematic review and meta- analysis of r and omized controlled trials to evaluate the analgesic efficacy and adverse effects of cannabinoids for chronic non-cancer pain .
A double-blind, randomized, placebo-controlled, parallel-group study of THC/CBD oromucosal spray in combination with the existing treatment regimen, in the relief of central neuropathic pain in patients with multiple sclerosis
Abstract Central neuropathic pain ( CNP ) occurs in many multiple sclerosis ( MS ) patients . The provision of adequate pain relief to these patients can very difficult . Here we report the first phase III placebo-controlled study of the efficacy of the endocannabinoid system modulator delta-9-tetrahydrocannabinol (THC)/cannabidiol ( CBD ) oromucosal spray ( USAN name , nabiximols ; Sativex , GW Pharmaceuticals , Salisbury , Wiltshire , UK ) , to alleviate CNP . Patients who had failed to gain adequate analgesia from existing medication were treated with THC/CBD spray or placebo as an add-on treatment , in a double-blind manner , for 14 weeks to investigate the efficacy of the medication in MS-induced neuropathic pain . This parallel-group phase of the study was then followed by an 18-week r and omized-withdrawal study ( 14-week open-label treatment period plus a double-blind 4-week r and omized-withdrawal phase ) to investigate time to treatment failure and show maintenance of efficacy . A total of 339 patients were r and omized to phase A ( 167 received THC/CBD spray and 172 received placebo )  . Of those who completed phase A , 58 entered the r and omized-withdrawal phase . The primary endpoint of responder analysis at the 30 % level at week 14 of phase A of the study was not met , with 50 % of patients on THC/CBD spray classed as responders at the 30 % level compared to 45 % of patients on placebo ( p = 0.234 ) . However , an interim analysis at week 10 showed a statistically significant treatment difference in favor of THC/CBD spray at this time point ( p = 0.046 ) . During the r and omized-withdrawal phase , the primary endpoint of time to treatment failure was statistically significant in favor of THC/CBD spray , with 57 % of patients receiving placebo failing treatment versus 24 % of patients from the THC/CBD spray group ( p = 0.04 ) . The mean change from baseline in Pain Numerical Rating Scale ( NRS ) ( p = 0.028 ) and sleep quality NRS ( p = 0.015 ) scores , both secondary endpoints in phase B , were also statistically significant compared to placebo , with estimated treatment differences of −0.79 and 0.99 points , respectively , in favor of THC/CBD spray treatment . The results of the current investigation were equivocal , with conflicting findings in the two phases of the study . While there were a large proportion of responders to THC/CBD spray treatment during the phase A double-blind period , the primary endpoint was not met due to a similarly large number of placebo responders . In contrast , there was a marked effect in phase B of the study , with an increased time to treatment failure in the THC/CBD spray group compared to placebo . These findings suggest that further studies are required to explore the full potential of THC/CBD spray in these patients
Pain intensity of chronic non-cancer patients was reduced by cannabinoids consumption , but effect sizes were small .
Efficacy for neuropathic and non-neuropathic pain was similar
There is growing interest in using cannabinoids for chronic pain .
We performed a systematic review and meta- analysis of r and omized controlled trials to evaluate the analgesic efficacy and adverse effects of cannabinoids for chronic non-cancer pain .