Feb. 21, 2000 (Washington) -- It's the drug that hooks cigarette smokers, sending many of them to an early grave. But it may actually help patients with Parkinson's disease, Alzheimer's, Tourette's syndrome, and several other neurological disorders. The drug is nicotine, and it and other related compounds have shown promise in several recent clinical trials, according to results presented here Monday at the annual meeting of the American Association for the Advancement of Science.
The use of nicotine as a drug is nothing new, says Paul Sanberg, PhD, DSc, a professor of neuroscience at the University of South Florida. People in South America were using tobacco in the time of Columbus, and early explorers imported the plant to Europe. "I doubt there is a much older drug," says Sanberg, who is also chief scientific officer at Layton BioScience Inc.
Over the years, there have been hints of possible beneficial effects of nicotine, says another researcher, Paul Newhouse, a professor of psychiatry at the University of Vermont College of Medicine.
As early as the 1920s, researchers were testing it to treat Parkinson's disease, a debilitating neurological disorder that affects about 1% of the population, causing rigidity, slow movement, tremors, and in many cases, dementia. And over the years, 34 studies of large populations have found that smokers are less likely than nonsmokers to contract Parkinson's disease, Newhouse tells WebMD.
But those early results were not followed up until recent years. To see if nicotine really eased the symptoms of Parkinson's, Newhouse and his colleagues conducted a small study on 11 men and four women with Parkinson's disease. The patients, who averaged 66 years of age, did not suffer from dementia.
The study participants wore a nicotine patch on their skin for 16 hours a day. After two weeks, researchers tested the patients' ability to rise out of a chair, cross a room, and come back and sit down, Newhouse tells WebMD.
Overall, the nicotine treatment made it easier for the men and women to move, he says. It also improved performance on several tests that gauge attention and memory. And many of the effects persisted two weeks after the treatment was finished, he says. But not all the effects were beneficial. "It actually seems to make tremors worse," he says.
Newhouse says that no one knows whether the drug will be beneficial when it is taken for years. That means that it is too soon to recommend a nicotine patch or gum to Parkinson's patients. "It would be rash to suggest that people go out and buy the patch," he says. The study is slated to be published later this year.
Nicotine's effects on memory suggest that it, or related compounds, also may help treat Alzheimer's patients. In three preliminary studies testing this possibility, nicotine, or a nicotine look-alike drug called ABT-418, improved the performance of Alzheimer's patients on tests of memory and attention.
Nicotine analogs also proved effective against Tourette's syndrome, Sanberg says. In initial studies conducted several years ago, Sanberg's team had shown that nicotine patch and nicotine gum could ease the symptoms of Tourette's syndrome in children. Such symptoms include facial tics and a tendency to spout repeated obscenities.
At the meeting, Sanberg presented recent results from a new study that tested the effects of a drug called mecamylamine on children aged 8 to 17 with Tourette's syndrome. Mecamylamine, which works in a similar way to nicotine, is FDA approved to treat high blood pressure and is sold under the name Inversine.
Two weeks of daily mecamylamine pills reduced Tourette's symptoms, while placebo pills had no effect. Although the FDA has not yet approved mecamylamine to treat Tourette's, nicotine patches seem to have the same effect, says Sanberg.
"The data says that if [children with severe symptoms] aren't being treated with other medications, that the nicotine patch might be useful," he says.