Managing opioid dependence. Comparing buprenorphine with methadone.
analysis comparing the effectiveness of buprenorphine and methadone. Research question Is buprenorphine as effective as methadone for managing opioid dependence? Type of article and design Meta-analysis by three reviewers. Relevance to family physicians Community-based family physicians are uniquely suited to care for opioid-dependent patients. Buprenorphine, like methadone, is a substitution treatment for opioid dependence. Buprenorphine is available in Canada only through a special access program, which is not currently enrolling new patients. Now that the United States Food and Drug Administration has approved primary care physicians' prescribing of buprenorphine, we expect it will soon be available in Canada. Compared with methadone, buprenorphine has certain theoretical advantages. The most notable phar-macokinetic difference is that buprenorphine has a substantially longer half-life than methadone. Methadone patients generally require once-daily dosing, but many buprenorphine patients can be treated once every 2 or 3 days. This has important clinical implications, because many opioid-dependent patients have to go to a pharmacy for supervised ingestion of methadone or buprenorphine. Lessening the burden of daily pharmacy visits might improve some patients' lives. Also, as mentioned in this meta-analysis, many patients have diffi culty discontinuing methadone because they suffer interdose withdrawal, which frequently occurs with lower doses. Theoretically, this should be less of a problem with buprenorphine. The most notable pharmacodynamic difference is that methadone is a full opioid agonist at the µ-receptor, while buprenorphine is a partial agonist. Buprenorphine is limited in its ability to cause respiratory depression, which makes lethal overdoses less likely. Furthermore, its use potentially results in less severe physical dependence , making detoxifi cation easier. Over view of study and outcomes MEDLINE and PsycINFO were searched from 1974 to 2000 for articles reporting controlled comparisons of buprenorphine and methadone. To be included, studies had to provide quantifi able data on both treatment effi cacy as determined by ongoing illicit opioid use and the total number of subjects testing positive and negative for illicit opioids at the end of the study period. Reviewers excluded studies in which participants had coexisting psychiatric disorders or reported a primary drug of abuse other than an opioid. Of more than 1595 articles found, nine met the inclusion criteria. The only common outcome measure across all studies was urine toxicology screening. Results The authors determined the dif ference between methadone and buprenorphine using the statistical method of " effect size. " In this case, the effect size measured the effectiveness …