The anti-epileptic drug vigabatrin (Sabril) can stop cocaine use by addicts, in part by eliminating their craving for cocaine, according to the first study to assess the treatment's effects on users.
Twenty people (19 men and one woman) who had been using cocaine daily for three to 15 years, were enrolled. All of the addicts had expressed a desire to kick their habit. Under the trial's guidelines, they had to provide urine samples twice a week and answer daily questionnaires about their drug use and cravings. Their urine was screened for several drugs, including cocaine, heroin, methamphetamine, and tetrayhdrocannabinol, the active ingredient in marijuana. In addition, the addicts received psychosocial counseling at the clinic.
In the first week of the trial, subjects received escalating doses of vigabatrin up to a maximum of three grams daily. They were then put on a daily maintenance dose of four grams. In order to complete the trial, they had to remain free of cocaine for 28 consecutive days. After this four-week cocaine-free period, they were tapered by one gram per day per week for each of the following three weeks before they ended their treatment.
In the first ten days of the trial, eight subjects dropped out because they didn't want to stop using cocaine. Among the 12 remaining subjects, eight (or 40 per cent of the total enrolled) completed the trial and were tapered off vigabatrin. At the time of the study's online publication, all eight of the subjects remain free of cocaine more than four weeks after their vigabatrin treatment ended. Moreover, the people who quit using cocaine reported that their craving did not return once they tapered off vigabatrin.
Four of the 12 subjects who remained in the study more than ten days were never able to stop using cocaine during the trial, even though they also took vigabatrin. However, three of these people were able to reduce the amount of cocaine they took substantially, by 50 to 80 per cent, according to the study.
None of the subjects in the study reported disturbances in their vision, a known potential side-effect of vigabatrin. The only major side-effects were daytime sleepiness and headaches that occasionally persisted for several weeks but were never serious enough for affected subjects to request leaving the trial. In addition, all of the people who stopped using cocaine gained weight.
Dr Brodie said:
"Our results, in which 40 per cent of hard-core addicts were able to stay clean for more than 60 days, were more spectacular than we would have ever dreamed. These addicts were able to stay clean even without leaving the environment that had fostered their addiction. They gained weight, they got jobs, and they are now living with their families."