Posts Tagged ‘buprenorphine in pregnancy’

Opioid Addiction in Pregnancy: More Information about the Use of Methadone Versus Buprenorphine

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The MOTHER (Maternal Opioid Treatment: Human Experimental Research) trial of 2012 (Jones et al) gave us much-needed information about how buprenorphine compares to methadone when used to treat opioid-addicted pregnant women. This landmark study showed us buprenorphine can be just as effective as methadone. Babies born to moms on buprenorphine had the same incidence of opioid withdrawal (called neonatal abstinence syndrome, or NAS) at 50%, but the withdrawal was significantly less severe, the babies required about half the medication as the babies born to moms on methadone. Also, buprenorphine-exposed babies spent significantly less time in the hospital – about half as long as methadone-exposed infants.

Some doctors point out that more women on buprenorphine dropped out of that study than women on methadone, and say that proves buprenorphine is less effective. However, the majority of those women didn’t leave treatment; they just left the buprenorphine arm of the study.

This week I read another study, by Meyer et al, soon to be published in the Journal of Addiction Medicine. This study also looked at pregnant patients being treated for opioid addiction.

The authors of this new study pointed out that the MOTHER trial was a placebo- controlled, double- blind study comparing buprenorphine with methadone, but in real life, the decision to start an opioid-addicted pregnant woman on buprenorphine versus methadone is more complex, and determined by other factors. So the study by Meyer et al did a retrospective analysis. They looked at cases where the choice of buprenorphine versus methadone was made by the patient and physician, as happens in real life, then studied the outcomes. The authors of the new study believed findings will be more pertinent to what happens in everyday clinical practice.

In this retrospective cohort study, 609 pregnant patients were started on either buprenorphine (361) or methadone (248). This study took place over the years from 2000 to 2012 at a single site, University of Vermont.

The study collected various data about the newborns: their sex, estimate gestational age at delivery, birth weight, head circumference, length of stay in the hospital, whether the baby received breast milk, and if the child was sent home with the mother. The study also looked at if the newborn has NAS and if the baby needed medication, and length NAS treatment.

In the results, first-time mothers were significantly more likely to start buprenorphine than methadone. Mothers positive for Hepatitis C were more likely to be started on methadone. In both groups, more than 80% of the moms were smokers. About 30% of both groups had to have a C-section at delivery.

Both groups had similar prenatal care; more than 65% of the mother in both groups initiated care within the first trimester. However, women in the buprenorphine group were significantly more likely to get what the authors defined as “adequate” prenatal care. Women on buprenorphine were also more likely to already be in treatment when they became pregnant, compared to the women in the methadone group.

Nineteen women switched from buprenorphine to methadone, out of the three-hundred and sixty-one women who started on buprenorphine. Only five of those patients switched because buprenorphine was not strong enough for them, or other medication side effects. Most were switched to methadone because they needed more intensive monitoring at an opioid treatment program due to continued positive urine drug screens. Only three women out of the three-hundred and sixty-one started on buprenorphine dropped out and were lost from treatment.

No women were switched from methadone to buprenorphine, as one would expect. That’s because in order to switch from a full opioid, methadone, to a partial opioid, buprenorphine, the pregnant opioid addict would have to go into at least mild withdrawal, thus putting her at risk for adverse events. That’s not a risk most doctors are willing to consider.

Babies born to moms on buprenorphine, as compared to methadone, were significantly more likely to have longer gestational age. This is a good thing, because it means there were significantly fewer preterm deliveries on buprenorphine compared to methadone. The babies born to moms on buprenorphine were significantly more likely to have higher birth weights and bigger head circumference.

Just like what we saw in the MOTHER trial, this study also showed that the infants born to moms on buprenorphine required significantly less medication to treat neonatal abstinence syndrome. The buprenorphine-exposed babies required medication for a significantly shorter time than methadone-exposed newborns.

More than 95% of the infants were sent home in the care of the mother or family, which makes me think this study was done on women with fairly good stability at the time of delivery.

The authors of the study concluded that this evidence suggests that buprenorphine gives outcomes that are at least as good as with methadone.

I’d take that conclusion one step farther and say we now have several studies that show less neonatal withdrawal in babies exposed prenatally to buprenorphine compared to methadone. I have to ask myself: knowing what I do from these studies, which medication would I want to take during pregnancy? I’d prefer buprenorphine, and if it didn’t work for any reason, I’d switch to methadone.

I explain all of this to pregnant patients with opioid addiction upon admission, though I’m careful to also point out that methadone is still officially the gold standard in many places.

I think that will change soon. We are getting more information that shows outcomes equal to methadone with less severe neonatal withdrawal.