Marijuana Relieves Chronic Neuropathic Pain

2010-08-30 03:45

Chronic neuropathic pain is difficult to treat, but a new study suggests that smoked marijuana (cannabis) is an effective therapy for this challenge. Scientists found that smoking marijuana reduces pain, improves mood, and helps sleep.

Marijuana as Medicine
Medical marijuana is often in the news, and while controversial for various reasons, study after study show that cannabis in various forms can be helpful in treating a variety of conditions. Recently (February 2010), researchers at California’s Center for Medicinal Cannabis Research reported study findings regarding the therapeutic benefits of smoking marijuana for treating pain-related conditions. The studies were the first ever conducted on the therapeutic value of smoked marijuana in the United States in more than two decades.

Spray marijuana also recently demonstrated effectiveness in reducing cancer pain, especially in patients who had not gotten relief from morphine or other medications. Six studies also showed that extracts of marijuana significantly reduced spasms in patients who have multiple sclerosis. Yet other research indicates that marijuana is beneficial in patients who have post-traumatic stress disorder, including returning war veterans.

New Marijuana Pain Study

The new study, which was conducted at McGill University, appears to be the first outpatient clinical trial of smoked marijuana ever reported. Study participants included 21 adults age 18 years and older with chronic neuropathic pain. Three different potencies of active drug (THC; tetrahydrocannabinol) were used: 2.5 percent, 6 percent, and 9.4 percent, along with a 0 percent placebo.

The randomized, controlled trial revealed that 25 mg cannabis with 9.4 percent THC taken as a single smoked inhalation three times daily for five days significantly reduced pain intensity when compared with placebo in patients who had chronic post-traumatic/post-surgical neuropathic pain. Dr. Mark Ware, director of clinical research at the Alan Edwards Pain Management Unit of McGill’s Health Center noted that he and his team “found statistically significant improvements in measures of sleep quality and anxiety” as well.

Currently, people who suffer with chronic neuropathic pain can take opioids, antidepressants, anticonvulsants, and local anesthetics, but these drugs have significant side effects and their efficacy is highly variable. Marijuana in oral form (extracts, spray) have been somewhat successful in treating some types of pain, but they may have different effects and risks than smoked cannabis.

Unlike “normal” pain, which results from stimulation of pain receptors in the body, neuropathic pain results from damage to or dysfunction of the central or peripheral nervous system. Such pain is out of proportion to tissue injury, and it can develop after damage to any level of the nervous system. Some specific chronic neurological pain syndromes include postherpetic neuralgia, polyneuropathy (often associated with diabetes), postsurgical pain syndromes, complex regional pain syndrome, carpal tunnel syndrome, and herniated disk.

The McGill study is one of only a few scientific attempts to evaluate the impact of smoked marijuana on chronic neuropathic pain, and the results are promising. The authors recommend more research on this topic, using higher potencies of THC, more flexible dosing, longer follow-up, and long-term safety studies.

SOURCES:
McGill University
Merck Manual

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