TAMPA, Fla (Sept. 17, 2001) — A nicotine patch boosts the effectiveness of drugs administered to relieve the involuntary movements and other symptoms of Tourette's syndrome — even when the drug dosage is cut in half, a University of South Florida College of Medicine study found.
The double-blind, placebo-controlled study, published in the September issue of the Journal of Clinical Psychiatry, was funded by the National Institute of Neurological Disorders and Stroke and the Tourette's Syndrome Association of America. It demonstrated that a low-dose nicotine patch may be useful, particulary in alleviating the motor tics of children with Tourette's syndrome.
"Not only was the nicotine patch effective, but a much smaller dose of the medication haloperidol could be given," said first author Archie Silver, MD, USF professor of psychiatry. "That's especially important when treating children and adolescents."
Physicians typically treat Tourette's with haloperidol (Haldol) or drugs of a similar class, powerful tranquilizers that helps control symptoms but often may also severely slow down motor function and dull the ability to think.
The USF study builds on a growing body of research showing that the chemical nicotine, separated from its addictive effect in tobacco, may have therapeutic benefits for those with neuropsychiatric disorders.
The researchers followed 70 patients with Tourette's syndrome, ages 8 to 18, who received Haldol and a daily 7-mg nicotine patch, similar to the over-the-counter ones used by smokers trying to quit. Nicotine in the patch is absorbed through the skin and reaches its maximum level in the blood in about three hours — much more slowly than by smoking a cigarette.
Half the children and adolescents received real patches and the other half were given inactive, or control, patches.
The study found that the severity and frequency of motor tics were substantially relieved for those with the active nicotine patches. They did better than the control group, both when receiving the optimal dose of Haldol and when the Haldol dose was reduced by 50 percent. Even when their patches were removed for two weeks, patients who had been exposed to nicotine continued to have superior symptom control with lower than usual doses of Haldol.
There was no evidence of nicotine dependence, but those with the nicotine patch experienced more side effects, primarily nausea and dizziness. Nicotine-related side effects may limit widespread use of the patch for supplemental treatment of Tourette's, the researchers conclude, but an occasional patch may be worth trying for patients who cannot control their symptoms with standard drugs.
The researchers are unsure how nicotine works to control sudden involuntary movements, but they suspect that the chemical may turn off a specific nicotine receptor involved in the brain chemistry of people with Tourette's.
"This study is important because it focuses attention on a nicotine receptor system in the brain that has been underemphasized in neurodevelopmental disorders of childhood until now," Dr. Silver said.
The real interest in nicotine as a potential therapy is shifting to the search for artifical compounds that would mimic the effects of the drug without its addictive risks or unwanted side effects.
"Now that we understand more about how nicotine works in the brain, we're looking for nicotine substitutes that could more precisely target specific brain disorders and have fewer side effects than the patches," said principal investigator Paul R. Sanberg, PhD, DSc, professor of neurosurgery and director of the Neuroscience Program at USF.
For example, Dr. Sanberg said, another USF double-blind study reported this month in the Journal of the American Academy of Child and Adolescent Psychiatry, found that the drug mecamylamine (Inversine) appeared to be safe for children and to help those who experience mood disorders such as depression, aggression or anxiety along with Tourette's syndrome. Further research is needed to determine if mecamylamine can also boost Haldol's effectiveness in reducing motor tics in the same way that nicotine does. The mecamylamine study was funded by Layton Bioscience Inc.
Materials provided by University Of South Florida Health Sciences Center. Note: Content may be edited for style and length.
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