A recent study has shown that levomethadyl acetate (LAAM), buprenorphine, and high doses of methadone (60-100 mg.) were much more effective in treating heroin addiction than low-dose methadone maintenance (20 mg.). LAAM and methadone are available for clinicians to prescribe. Buprenorphine is currently under review by the Food and Drug Administration and is used only in research studies.
"There are nearly one million chronic users of heroin in the United States, and this study is important because it helps to identify the most effective treatments for this devastating addiction," explained Dr. Alan I. Leshner, director of the National Institute on Drug Abuse (NIDA), National Institutes of Health, which provided funding for the research. "This study also furthers our knowledge about the effectiveness of buprenorphine and, ultimately, it may expand the treatment options available to physicians."
A research team led by Dr. Rolley E. Johnson at the Johns Hopkins University School of Medicine conducted the study, published in the November 2 issue of the New England Journal of Medicine.
Dr. Johnson's team compared treatment results in 220 volunteers between the ages of 21 and 55, diagnosed as heroin dependent. The volunteers were randomly assigned to one of four treatment groups: LAAM, buprenorphine, high-dose methadone (60 to 100 mg), or low dose methadone (20 mg). There were 55 patients in each group.
For all four treatment groups, reported heroin use decreased by about 90% after entering treatment. In addition, all measures-length of time remaining in the study, heroin use during the study, and ratings of drug problem severity-were better for subjects in the LAAM, buprenorphine, and high-dose methadone groups than for those in the low-dose methadone group. All three treatments markedly reduced illicit heroin use. There was little difference in treatment outcomes among the LAAM, buprenorphine, and high-dose methadone treatment groups. LAAM produced the longest duration of continuous abstinence; buprenorphine was similar to LAAM in terms of retention in the study and to high-dose methadone in terms of abstinence.
In the 17-week study, retention rates ranged from 72.7 percent (high-dose methadone group) to 20 percent (low-dose methadone group). LAAM, buprenorphine, and high-dose methadone patients submitted fewer heroin-positive urine samples than did low-dose methadone patients. The percentage of patients with 12 or more consecutive heroin-negative urine specimens differed significantly across the groups. More than one-third of the LAAM patients had 12 or more consecutive negative urine specimens, while only 8 percent of the low-dose methadone patients achieved this number. The percentage of high-dose methadone and buprenorphine patients reaching this mark was only slightly less than the LAAM group.
Patients in the LAAM and buprenorphine groups were given these drugs three times a week, and patients in both methadone groups received daily doses. Dr. Johnson said that not having to administer LAAM or buprenorphine on a daily basis gives these drugs a clinical advantage. "Less-than-daily dosing," he says, "reduces the need for take-home medication, requires fewer clinic visits, and allows a more normal lifestyle."