Study: Medical pot relieves pain

February 11, 2007

Liz Highleyman, Bay Area Reporter

Medical cannabis can alleviate pain due to peripheral neuropathy in people with HIV, according to a new study from researchers at the University of California at San Francisco published in the February 13 issue of Neurology.

Peripheral neuropathy is a type of nerve damage that usually starts in the feet and can cause sensations ranging from numbness or tingling to sharp pain. It is a side effect of many medications, including certain cancer chemotherapies and antiretroviral drugs used to treat HIV, and is also common among patients with diabetes and multiple sclerosis.

The randomized, placebo-controlled trial, conducted by UCSF's Dr. Donald Abrams and colleagues, included 50 volunteer participants with HIV-associated sensory neuropathy who had experienced pain for an average of six years.

To accurately measure the effects of cannabis used in the study, participants were asked to stop using marijuana obtained from other sources for two days, and spent a week at a special facility at San Francisco General Hospital. Half received marijuana cigarettes containing 3.5 percent THC – considered a low amount compared with cannabis available through buyers' clubs or on the street – while the rest used similar placebo cigarettes with the active cannabis compounds removed.

After five days, patients who smoked marijuana three times daily reported an average 34 percent reduction in pain – twice as much as those who smoked the placebo cigarettes. In addition, half of the volunteers who used cannabis experienced at least a 30 percent reduction in pain, compared with just one-quarter of those who used placebo cigarettes.

"This placebo-controlled clinical trial showed that people with HIV who smoked cannabis had substantially greater pain reduction than those who did not smoke cannabis," said Abrams. "These results provide evidence that there is a measurable medical benefit to smoking cannabis for these patients."

David Murray, Ph.D., chief scientist for the White House Office of National Drug Control Policy, said the study was "not terribly convincing" due to its small size and what he called methodological problems. He also contended that smoking marijuana could lead to bacterial infections in the lungs, thus posing a danger for patients with compromised immune systems.

Despite the advent of effective anti-HIV drug cocktails, as many as one in three people with HIV/AIDS still experience neuropathy, estimated study co-author Dr. Cheryl Jay, and there are currently no FDA-approved treatments for HIV-related nerve pain.

"This study suggests new avenues to manage neuropathic pain in this setting," she said.

Study participant Diana Dodson, who has been living with HIV for 21 years, said that prescribed opiates and the FDA-approved THC pill dronabinol (Marinol) do not work as well as smoked marijuana and cause unwanted side effects such as grogginess.

"Cannabis controls my pain and it allows me to function," she said. "I need the government to grant me safe access to my medicine."

Barriers to research

The neuropathy study is the first rigorous, controlled study in two decades to demonstrate the therapeutic benefits of smoked marijuana. It is also the first of about a dozen medical marijuana trials conducted under the auspices of the state-funded Center for Medicinal Cannabis Research, operated by the UC system.

Under current federal policies, researchers who wish to study medicinal cannabis must receive clearance from several government agencies including the Drug Enforcement Administration and the National Institute on Drug Abuse. Abrams first sought approval for his study in the early 1990s, but was repeatedly denied.

The only approved source of cannabis – widely reported to be of low quality – is a government-run farm in Mississippi. However, DEA Administrative Law Judge Mary Ellen Bittner ruled this week in favor of a proposal by University of Massachusetts professor Lyle Craker, Ph.D., to begin growing marijuana under controlled conditions for research purposes [see story "Judge tells DEA to issue license to grow pot for research"].

Advocates respond

Following the release of the study results on Monday, patient advocates from the National Association of People With AIDS and Americans for Safe Access called on Congress to hold hearings on medical marijuana. Despite a favorable report by the Institute of Medicine in 1999 that recommended further research, the federal government continues to maintain that cannabis has no recognized medical benefits.

NAPWA estimates that as many as one-third of people with HIV/AIDS have used cannabis to relieve neuropathy and other symptoms associated with the disease or its treatment.

"This study validates what individuals living with HIV/AIDS and their doctors have known for years," said NAPWA's Thomas Kujawski. "People with HIV deserve medications that support the highest quality of life. We call on Congress to put patients before politics and support this research."

"This study directly contradicts the federal government's assertion that marijuana is not a safe and effective medicine," added Rob Kampia, executive director of the Marijuana Policy Project. "It's time for our government to wake up, smell the science, and change the law to allow suffering patients legal access to medical marijuana."

Barbara Roberts, Ph.D., ASA's director of medical and scientific affairs and a former analyst with the White House Office of National Drug Control Policy, suggested that in addition to people with HIV, medical cannabis could also help injured war veterans coping with neurological pain.

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