Conclusions and Relevance Cannabinoid drugs may prevent the onset of pain by producing small increases in pain thresholds but may not reduce the intensity of experimental pain already being experienced ; instead , cannabinoids may make experimental pain feel less unpleasant and more tolerable , suggesting an influence on affective processes .
Cannabis-induced improvements in pain-related negative affect may underlie the widely held belief that cannabis relieves pain
Importance Cannabinoid drugs are widely used as analgesics , but experimental pain studies have produced mixed findings .
The analgesic properties of cannabinoids remain unclear .
Objective To conduct a systematic review and meta- analysis of the association between cannabinoid drug administration and experimental pain outcomes in studies of healthy adults .
The analgesic effect of oral delta-9-tetrahydrocannabinol (THC), morphine, and a THC-morphine combination in healthy subjects under experimental pain conditions
From folk medicine and anecdotal reports it is known that Cannabis may reduce pain .  In animal studies it has been shown that delta‐9‐tetrahydrocannabinol ( THC ) has antinociceptive effects or potentiates the antinociceptive effect of morphine . The aim of this study was to measure the analgesic effect of THC , morphine , and a THC‐morphine combination ( THC‐morphine ) in humans using experimental pain models .  THC ( 20 mg ) , morphine ( 30 mg ) , THC‐morphine ( 20 mg THC+30 mg morphine ) , or placebo were given orally and as single doses . Twelve healthy volunteers were included in the r and omized , placebo‐controlled , double‐blinded , crossover study . The experimental pain tests ( order r and omized ) were heat , cold , pressure , single and repeated transcutaneous electrical stimulation . Additionally , reaction time , side‐effects ( visual analog scales ) , and vital functions were monitored . For the pharmacokinetic profiling , blood sample s were collected . THC did not significantly reduce pain . In the cold and heat tests it even produced hyperalgesia , which was completely neutralized by THC‐morphine . A slight additive analgesic effect could be observed for THC‐morphine in the electrical stimulation test . No analgesic effect result ed in the pressure and heat test , neither with THC nor THC‐morphine . Psychotropic and somatic side‐effects ( sleepiness , euphoria , anxiety , confusion , nausea , dizziness , etc . ) were common , but usually mild
Conclusions and Relevance Cannabinoid drugs may prevent the onset of pain by producing small increases in pain thresholds but may not reduce the intensity of experimental pain already being experienced ; instead , cannabinoids may make experimental pain feel less unpleasant and more tolerable , suggesting an influence on affective processes .
Cannabis-induced improvements in pain-related negative affect may underlie the widely held belief that cannabis relieves pain
Importance Cannabinoid drugs are widely used as analgesics , but experimental pain studies have produced mixed findings .
The analgesic properties of cannabinoids remain unclear .
Objective To conduct a systematic review and meta- analysis of the association between cannabinoid drug administration and experimental pain outcomes in studies of healthy adults .