BUPRENORPHINE VERSUS METHADONE-MAINTENANCE FOR OPIOID DEPENDENCE

Buprenorphine at 2 mg and 6 mg daily was compared with methadone at 35 mg and 65 mg during 24 weeks of maintenance among 125 opioid-dependen t patients. As hypothesized, 6 mg of buprenorphine were superior to 2 mg of buprenorphine in reducing illicit opioid use, but higher dosage did not improve treatment retention. Self-reported illicit opioid use declined substantially in all groups, but by the third month, signific antly more heroin abuse was reported at 2 mg than at 6 mg of buprenorp hine or of methadone. From an initial average of $1860/month, month 3 usage dropped to $41 (methadone 65 mg), $73 (methadone 35 mg), $118 (b uprenorphine 6 mg), and $351/month (buprenorphine 2 mg). Days of use a lso dropped from 29 days to 1.7 (methadone 65 mg), 2.8 (methadone 35 m g), 4.0 (buprenorphine 6 mg), and 6.6 days/month (buprenorphine 2 mg). This relatively low efficacy for 2 mg of buprenorphine persisted thro ugh month 6 of the trial, with 7.2 days/month and $235/month of use fo r buprenorphine at 2 mg versus 1.9 days/month and $65/month for the ot her three groups. Increased opioid abuse also was associated with sign ificantly greater and persistent opioid withdrawal symptoms. Our secon dary hypothesis, that buprenorphine would be equivalent to methadone i n efficacy, was not supported. Treatment retention was significantly b etter on methadone (20 vs. 16 weeks), and methadone patients had signi ficantly more opioid-free urines (51% vs. 26%). Abstinence for at leas t 3 weeks was also more common on methadone than buprenorphine (65% vs . 27%). Thus, methadone was clearly superior to these two buprenorphin e doses, but illicit opioid use was reduced more by higher than lower buprenorphine dosage. Future studies need to examine higher sublingual buprenorphine doses of 12 mg to 20 mg daily for potential efficacy.