The cannabis plant has been used as a medicine for thousands of years. In the United States, doctors could prescribe marijuana cigarettes to patients for a variety of conditions until the 1940s, when it was banned. Marijuana's status as an illegal drug has removed it from the official medical arsenal, but its therapeutic power is still attracting attention, especially its pain-killing properties.
About 30 percent of HIV patients develop painful nerves during the course of their illness, and this neuropathy is extremely difficult to treat with standard pain medications. Dr. Donald Abrams, of the University of California at San Francisco, studied the use of marijuana for relief of their discomfort. "We've known for along time that cannabinoids, the active ingredients in marijuana, can be involved in modulation of pain and the response to pain," he explains, adding that the body has its own cannabinoid system. "We make natural substances called endo-cannabinoids and it's felt that one of the main roles of these endo-cannabinoids is in our processing of painful stimuli."
Abrams studied 50 patients who had suffered nerve pain for an average of 7 years. He gave half actual marijuana cigarettes to smoke three times a day, the other half smoked placebo cigarettes. He found the patients smoking the marijuana had significantly greater pain relief, and it was almost immediate. "After smoking the first cigarette on the first day," he recalls, "we asked patients what had happened to their pain. Those smoking the actual marijuana cigarette, their pain reduced 75 percent; where those smoking the placebo, their pain reduced less than 20 percent." These results were consistent throughout the study.
Abrams says there is a pill on the market containing the most active ingredient of marijuana, called tetrahydrocannabinol, or THC. But he says smoking the actual plant works better than taking the pill, because THC is only one of the components present in the plant. "The plant has over 400 chemical compounds, many of which also have medicinal value. Many of those compounds in the plant also offer a balance to the side effects of the THC alone. So when you take a pill that's just THC, some people have more adverse effects than actually smoking THC as part of marijuana."
The research appears in the February 13th issue of Neurology, the scientific journal of the American Academy of Neurology.