2:00 a.m. Aug. 22, 2002 PDT
By Randy Dotinga
SAN DIEGO -- Turning marijuana into a prescription medicine is a challenge -- and not just because pot is illegal.
Patients with cancer and AIDS insist that the nation's most popular recreational drug relieves their pain and nausea, but as they get stoned their motivation often vanishes too. Not to mention that inhaling smoke five times a day can increase sick people's risk of lung cancer and emphysema.
In a flurry of new research, scientists are trying to smoke out a solution. They're developing ways to take the high out of marijuana and transfer its legendary powers to an inhaler or a tablet patients put under their tongue.
But a British expert told an international convention of pain experts this week that pot pills won't show up on pharmacy shelves anytime soon.
"We've got a long way to go," said Dr. Andrew Rice, a senior lecturer in pain research at Imperial College in London, at the 10th World Congress on Pain in San Diego. While people have used marijuana to relieve pain for thousands of years, there's little scientific evidence that it actually works in humans, he said.
New research projects may change all that.
In 1996, California became the first of eight states to allow sick people to smoke marijuana to ease their symptoms. Three years later, state legislators authorized funding for medical marijuana research projects at the University of California at San Diego and its sister campus in San Francisco.
While the federal government cracks down on the illegal cultivation and trafficking of marijuana, the National Institute on Drug Abuse actually provides the drug to researchers.
At UC San Diego, researchers sting the arms of test subjects with capsaicin, the active ingredient in red chili peppers, and check to see if they react differently to the pain after smoking pot.
Researchers working with animals use similar approaches on rats. They apply stinging chemicals to the rats and measure whether they appear to suffer less pain after getting doses of marijuana.
UCSD researchers will also test the effects that smoking marijuana has on cancer patients who suffer severe pain, on multiple sclerosis patients who hope to reduce their muscle spasms and on AIDS patients coping with nerve pain.
Some pain patients learn how to adjust their use of marijuana so they avoid getting high, Rice said. But researchers want to eliminate the side effects entirely.
"If someone is looking to carry on normal functioning in terms of the workplace, driving and dealing with daily life, you really don't want to go around stoned all the time," said Sumner Burstein, a professor of biochemistry at the University of Massachusetts Medical School in Worcester.
This week, Burstein is presenting the results of his work with marijuana-derived drugs at a national conference of the American Chemical Society in Boston. He has developed a synthetic compound that is 50 to 100 times more potent than THC -- an active ingredient in marijuana -- but that, unlike THC, doesn't make people high.
Researchers at a pharmaceutical company are in the second phase of testing the compound in people, Burstein said. He declined to identify the company, which he said doesn't want publicity.
Rice, the British expert, said he isn't so sure that marijuana-derived drugs are ready for prime time. Even so, he said, scientists have learned much in the past two years about how the chemicals in marijuana infiltrate the body and bind with the receptors that produce its effects.
Researchers have known about the active ingredient THC since 1964, and doctors can prescribe Marinol, a drug made from a synthetic form of it. But while some AIDS and cancer patients take Marinol to control nausea and improve appetite, experts say it's not as effective as marijuana itself because it doesn't absorb easily through the mouth.
Also, Marinol costs more than a joint. Drugstore.com offers Marinol in the highest dose available for $14 a pill.
Marijuana researchers face other obstacles. "These compounds are very difficult to work with," Rice said.
What's more, smoking isn't healthy -- although in some cases, long-term risks don't matter.
"If you have terminal cancer patients, they'll die before they run into the lung problem," said Dr. Mark Wallace, chief of a pain clinic at UCSD. But in general, doctors want to avoid "trading one problem for another."
Unfortunately, there aren't many alternatives to smoking. The body doesn't absorb marijuana well through the digestive system. That's why people tend to smoke pot instead of baking it in brownies.
Rice said scientists are looking at "delivering" marijuana in a fine mist with the help of an inhaler or through a sublingual pill that's absorbed under the tongue like some heart drugs.
But there are other options too. Some researchers think the solution may lie in the other end of the alimentary canal -- in a suppository.
Many patients will no doubt prefer to take marijuana the old-fashioned
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