For opioid-dependent women who are pregnant, buprenorphine appears to offer an effective, safe first-line alternative to methadone, according to a report in the Dec. 9 issue of the New England Journal of Medicine.
In a randomized clinical trial comparing pregnancy outcomes among women seeking treatment for opioid dependence, infants exposed in utero to buprenorphine developed significantly less severe neonatal abstinence syndrome than did infants exposed in utero to methadone, said Hendrée E. Jones, Ph.D., of the department of psychiatry and behavioral sciences and the department of obstetrics and gynecology at Johns Hopkins University, Baltimore, and her associates.
The study involved 175 women aged 18-41 years who were at 6-30 weeks’ gestation when they entered treatment for opioid dependence at eight sites in the United States, Austria, and Canada. Eighty-six were randomly assigned to receive oral buprenorphine and 89 to receive oral methadone in a double-blind fashion.
After delivery, their neonates were assessed for signs and symptoms of neonatal abstinence syndrome (NAS) twice a day for at least 10 days.
There were five primary neonatal outcomes. Three of these – percentage of neonates requiring NAS treatment, peak NAS scores, and head circumference – did not differ between the two study groups. However, two of the five primary outcomes – amount of morphine required to treat NAS and length of hospital stay – favored the infants in the buprenorphine group. On average, infants exposed to buprenorphine required 89% less morphine and spent 43% less time in the hospital (10 days vs. 17.5 days) than infants exposed to methadone.
"The benefits of buprenorphine in reducing the severity of NAS among neonates with this complication suggest that it should be considered a first-line treatment option in pregnancy," Dr. Jones and her colleagues said (N. Engl. J. Med. 2010;363:2320-31).
Neonates of mothers who received buprenorphine also required a significantly shorter period of treatment for NAS (4.1 days) than did neonates of mothers who received methadone, who required 9.9 days of treatment for NAS, they reported.
There were no differences in any maternal outcomes between women who took buprenorphine and those who took methadone.
Despite the comparable or even superior efficacy and safety of buprenorphine, there was one important drawback with the therapy: Women were more likely to discontinue treatment for opioid dependency with buprenorphine (33%) than with methadone (18%). Most (71%) of the women in the buprenorphine group who discontinued treatment cited "dissatisfaction" with the drug as their reason, while only 13% of those in the methadone group did so.
The benefits of buprenorphine therapy "must be considered in light of the markedly different rates of attrition," Dr. Jones and her associates said. Future research should focus on reducing this "dissatisfaction" as well as on identifying "subpopulations of pregnant patients who are more likely to have a response to one medication than to the other," they added.
This study was funded by grants from the National Institute on Drug Abuse. Buprenorphine tablets and the associated placebo were supplied by Reckitt Benckiser. Dr. Jones had no financial conflicts to disclose. One of Dr. Jones’ associates reported ties to a number of drug companies, and others had or were seeking federal grants.