Buprenorphine Treatment Safer Than Methadone for Infants of Opiate-Addicted Mothers

Barbara Boughton

May 21, 2010

May 21, 2010 ( UPDATED June 23, 2010 ) (San Francisco, California) — One of the largest American studies to date to investigate the safety and effectiveness of buprenorphine for opiate addiction in pregnancy has concluded that the drug is less harmful for neonates than methadone, results in less treatment for neonatal abstinence, and is associated with shorter hospital stays for the infant, according to research presented here at American Congress of Obstetricians and Gynecologists 58th Annual Clinical Meeting.

The study's conclusions contradict previous studies that found no difference in outcomes for neonates between the 2 treatments for opiate addiction.

Those previous studies might have been too small to yield definitive data or compromised by the widely varying scoring systems used to assess neonatal outcomes, according to lead researcher Michael Czerkes, MD, from the Maine Medical Center in Portland. "The implications of our study are that buprenorphine may yield better clinical outcomes for neonates and significantly decrease medical costs because of shorter hospital stays for infants," he said.

In the study, neonates born to mothers treated with methadone stayed in the hospital a mean of 1 week longer than those born to mothers treated with buprenorphine. That longer stay could have cost anywhere from $8,071 to $28,553, depending on how long the infant needed intensive care, Dr. Czerkes said.

Dr. Czerkes and colleagues retrospectively reviewed the medical charts of 101 methadone-treated and 68 buprenorphine-treated pregnant women from the Maine Medical Center between 2004 and 2008. Data collected included the mother's age, gestational age of the infant, form of delivery, comorbid conditions, other maternal medications (such as benzodiazepines or selective serotonin reuptake inhibitors), Apgar scores for the infant, fetal birth weight, and infant cord pH. Information on neonatal abstinence scores, length of hospital stay, and need for treatment was also analyzed.

There was no statistical difference in maternal characteristics between the 2 groups, but the mean neonatal abstinence score was significantly lower in the buprenorphine group than in the methadone group (10.7 vs 12.5; P < .0012). Babies of mothers treated with methadone also stayed in the hospital longer after birth (mean of 15.7 vs 8.4 days; P < .001). In all, 75% of neonates born to methadone-treated mothers required treatment for withdrawal, compared with 50% of those with buprenorphine-treated mothers (P < .001).

Buprenorphine has been approved an alternative to methadone therapy in the United States since 2002. Researchers have theorized that buprenorphine is safer for treating opiate-addicted pregnant women because it less readily crosses the placenta, Dr. Czerkes said. He noted that the drug is often more appealing to opiate-addicted patients because it can be administered in a month's supply, rather than requiring a daily clinic visit.

Researchers at the Maine Medical Center will not be conducting a randomized placebo-controlled trial of buprenorphine treatment in pregnancy, as was originally reported. Dr. Czerkes told Medscape Ob/Gyn & Women's Health that "it is absolutely against ethical principles to treat an opiate-addicted woman with placebo during pregnancy."

Dr. Czerkes mentioned during his presentation that a randomized trial comparing buprenorphine and methadone is currently enrolling, but it is not taking place at his institution.

Although the Maine study is promising, it leaves some questions about treatment with buprenorphine during pregnancy unanswered, said Haywood L. Brown, MD, Roy T. Parker Professor and Chair of Obstetrics and Gynecology at Duke University Medical Center in Durham, North Carolina.

"Why are the results different from previous studies?" he asked. "One reason may be that with methadone treatment, dosages tend to increase as the pregnancy advances," he said. The average dose of methadone is 100 mg, and the average dose for the patients in the Maine study was 102 mg. "If patients had been maintained on a lower dose of methadone, as in Europe where the typical dose is 50 to 60 mg, there might not have been a difference between the 2 groups in neonatal abstinence outcomes," Dr. Brown said.

However, opiate addicts who are treated with buprenorphine are more likely to take the drug because of ease of use, and thus more likely to obtain an even distribution through pregnancy, Dr. Brown added. "It's a very positive thing that the neonates in the study had better outcomes in regard to neonatal abstinence, and were in the hospital for a much shorter length of time. While we need more data to make any definitive conclusions, it's certainly a step in the right direction," he said.

Dr. Czerkes' study was awarded the Donald F. Richardson Memorial Prize.

Dr. Czerkes and Dr. Brown reported no relevant financial disclosures.

American Congress of Obstetricians and Gynecologists (ACOG) 58th Annual Clinical Meeting. Presented May 18, 2010.

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