番茄社区

LOS ANGELES, Nov. 28 - The high and cravings of methamphetamine addicts can be reduced by the same antidepressant that helps in smoking cessation (bupropion), researchers here reported.

Addicts who took Zyban Sustained-Release Tablets (bupropion) had significantly fewer cravings (p<.002) compared with those who took a placebo, and had a reduced high after using methamphetamine (p<.02), UCLA investigators reported in the online edition of Neuropsychopharmacology.

"These data provide a rationale for the evaluation of bupropion in the treatment of methamphetamine dependence," said Thomas F. Newton, Ph.D. "Bupropion's novel effect on the brain is what makes this line of research so promising."

Zyban inhibits the reuptake of dopamine and norepinephrine and also appears to boost dopamine neurotransmission, the research team said. It also inhibits "the inward transport of methamphetamine, thus limiting the ability of methamphetamine to displace dopamine from its vesicular stores," Dr. Newton and colleagues wrote. Under the brand name Wellbutrin, the drug is used to treat depression.

The double-blind trial compared 20 methamphetamine addicts between the ages of 18 and 45, half assigned to Zyban treatment the rest to a placebo. Sixty-five percent of the group was male and 55% of the cohort was non-Hispanic white. The mean age of the participants was 32.8 ± 8.4 years. In the previous 30 days, 75% reported also using nicotine, 55% reported using marijuana, and 85% reported consuming alcohol. All participants met the DSM-IV criteria for methamphetamine dependence.

At baseline, all received 0, 15, and 30 mg IV doses of methamphetamine. They then received a second identical series of methamphetamine six days after beginning their twice-daily oral Zyban therapy or placebo. The Zyban tablets were administered in 150 mg sustained-release doses.

The researchers used interviews, questionnaires and scales to assess the patients' responses to their treatments. For example, visual analog data was collected at 15 minutes before and then every few minutes afterward for up to eight hours following treatment administration. This data measured whether the patients felt "any drug effect," "high," "depressed," "anxious," a "desire for methamphetamine," or any good or bad effects.

The investigators also assessed physical symptoms, the impact of visual cues, such as having participants watch a video of actors using drugs, and subjective behavioral intentions.

Zyban was associated with a significant overall reduction in cravings. The antidepressant also appeared to blunt the effect of a methamphetamine high. The researchers said there was no evidence of toxicity and also no signs that the treatment increased the risk of further methamphetamine abuse.

On the contrary, "bupropion may reduce the abuse of liability of methamphetamine," Dr. Newton and colleagues wrote.

The authors pointed out several limitations to the study. In addition to the small number of participants, doses of both Zyban and methamphetamine were kept small. The researchers said more study is needed outside of the laboratory setting to determine Zyban's potential in treating methamphetamine addiction. It is also unclear how long treatment would be necessary to help patients recover from methamphetamine dependence, the researchers said. They plan to extend this study to a larger phase II trial.

Comment