The National Cancer Institute notes that, while more research is necessary, small studies have indicated the potential benefits of cannabis in helping cancer patients overcome the pain associated with their disease.
According to the NCI, a small study of 21 patients with chronic pain who combined vaporized cannabis with morphine experienced improved pain relief compared to patients who took only morphine. However, combining vaporized cannabis with oxycodone, a narcotic pain reliever and cough suppressant that is similar to morphine, did not produce significantly greater pain relief.
In addition, two small studies indicated that delta-9-THC, the main active cannabinoid in marijuana, helped to relieve pain as well as nausea and vomiting.
A second study indicated that delta-9-THC given in doses could provide pain relief similar to that provided by codeine, a pain-relieving drug derived from morphine.
The NCI also cites a study that indicated a cannabis plant extract medicine effectively relieved pain when sprayed under the tongue of advanced cancer patients whose pain was not relieved by strong opioids alone. That study also indicated that some patients were able to continue to control their cancer-related pain without needing higher doses of the cannabis spray or higher doses of other pain medications they were taking.