Inhaled marijuana appears to be a safe and effective treatment for chronic pain when used in addition to narcotics like morphine and oxycodone, according to a small UCSF study that is the first to look at the combined effects of the two classes of drugs in humans.
The study, published in this month’s edition of Clinical Pharmacology and Therapeutics, was designed primarily to look at whether taking marijuana with narcotics is safe, and researchers reported that there were no negative side effects from combining the drugs.
Overall, the 21 men and women in the study reported a roughly 25 percent reduction in pain after inhaling vaporized marijuana several times a day for five days.
If the results can be backed up in further studies, marijuana could prove an important means of augmenting the effects of narcotic drugs for the millions of people who suffer from chronic pain associated with cancer, AIDS and a variety of other conditions, said study author Dr. Donald Abrams, a UCSF professor and chief of the hematology-oncology division at San Francisco General Hospital.
“If we can get funded, we should do a study now with pain as the endpoint” and not just safety, Abrams said.
He added that scientists don’t yet understand how, exactly, marijuana and opiates interact in humans, but “our results support that the relationship between cannabis and opiates is synergistic.”
Multiple studies of medical marijuana have shown that the drug can be beneficial in treating pain. A drug called Sativex that combines the two main compounds of marijuana – cannabidiol (CBD) and delta-9 tetrahydrocannabinol (THC) – is currently in clinical trials for treatment of pain in cancer patients in the United States, and is already used in Europe and Canada.
Stands to reason
With what’s already known about marijuana’s pain-relieving effects, it’s not surprising that the drug, when used with narcotics, would increase pain relief, said researchers not associated with the new study.
“There’s already tons of data on cannabinoid pain relief and opiate pain relief, and it only makes sense that you’d get more pain relief from two drugs instead of one,” said Dr. Daniel Nomura, an assistant professor in the nutritional sciences and toxicology department at UC Berkeley.
Abrams himself pointed out that because his study is small, and because all of the patients knew they were inhaling marijuana and therefore could have experienced some pain relief from a “placebo effect,” it would be premature to start widely prescribing cannabis to pain patients. Still, the results were promising enough that he intends to attempt a second study to look more closely at pain relief.
But getting another study off the ground will be tough. The bar has been set high for acceptable uses of medical marijuana, Abrams said, and getting money and other resources – notably, the drug itself – to conduct research can be very difficult. Abrams’ study was funded by the National Institute on Drug Abuse, which also supplied the marijuana.
The patients in Abrams’ study were taking twice-daily doses of either morphine or oxycodone to treat chronic pain associated with a variety of conditions, such as arthritis, neuropathy, cancer and multiple sclerosis.
Patients stayed at San Francisco General Hospital during the study. They inhaled vaporized marijuana three times a day, for about 10 minutes at time. On the first day of the study, the mean pain score, on a scale of 0 to 100, was 39.6; after five days of marijuana therapy, their mean pain score was 29.1.
The hope, Abrams said, is that marijuana could someday be used either in conjunction with narcotics or as a replacement for narcotics to help curb some of the side effects associated with those medications.
Glenn Osaki of Pleasanton, a patient of Abrams who used to take drugs like morphine and oxycodone daily, said he’s been off narcotics since July 2010, after he started using medical marijuana to combat pain associated with colon cancer.
“I was out of it most of the time from the opiates,” said Osaki, 53. “It was hard having a decent quality of life, and I was just trying to figure out a way to manage my pain.”
Medical marijuana has only one side effect he doesn’t care for: the high.
“I used to smoke pot when I was a kid, just goofing around,” he said. “The stuff nowadays is pretty strong, so that is one thing I don’t really like now.”
At UC Berkeley, Nomura agrees. He and other biologists are studying ways to tap into the useful effects of cannabis without the drug high that comes with it.
“Obviously medicinal marijuana is still widely used. There are really undisputed beneficial effects,” Nomura said. “But in terms of moving forward with drug development, we need to develop safer drugs that don’t make you high.”
Source: San Francisco Chronicle (CA)
Author: Erin Allday, Chronicle Staff Writer
Published: December 7, 2011
Copyright: 2011 San Francisco Chronicle