Researchers reviewed the charts of 101 women who received care at a methadone maintenance treatment program between 2006 and 2010 after giving birth. They discovered that under the clinical assessment model—in which clinicians estimate patients’ methadone dose based on their individual physiologic parameters, rather than using a standard formula to reduce doses—women experienced on average only a small reduction in methadone dose. This suggests that, contrary to prior belief, changes in the physiology of women’s bodies from delivery to 12 weeks postpartum did not significantly affect their response to methadone.
Treatment for addiction in pregnant women is a complex topic. The gold standard for treatment is methadone maintenance, which has been shown to reduce illicit drug use and improve neonatal outcomes such as birth weight. Given the physical changes that happen to a woman’s body while pregnant, women often need higher doses to help them effectively manage their addiction during and after pregnancy. Yet, the optimal approach to adjusting methadone maintenance dosages during the postpartum period has long been unclear. Nonetheless, ensuring that women receive an appropriate dose is crucial to ensure ongoing sobriety while avoiding dangerous oversedation.
“This is an important issue because the postpartum period can be vulnerable for women struggling with opioid dependence, and it is crucial to ensure that the methadone dose is adequately high to continue to support recovery, while not causing oversedation,” said lead author Christine Pace, MD, an internist at BMC who specializes in addiction. “Oversedation is dangerous because women who are lethargic or sleepy are not able to care appropriately for themselves or their infants. In addition, patients who become over sedated from an excessive dose of methadone, with or without the addition of other medications or illicit drugs, may be at risk for overdose.”
The number of events where women appeared oversedated was slightly increased during the postpartum period, but still rare, occurring less than 6 times per 10,000 visit days. Many of the women who experienced these were also concurrently prescribed benzodiazepines. The authors caution that women receiving multiple sedating medications are particularly vulnerable and require more frequent surveillance.
“Our findings suggest that, given the physiologic changes and psychosocial stressors unique to the postpartum period, it is appropriate for methadone clinics to implement regular postpartum assessments at intervals extending at least up to 12 weeks after delivery. Clinicians also should take into account benzodiazepine use,” said Pace, also an assistant professor of medicine at BUSM. “Further studies are needed to guide safe and effective methadone dosing during the postpartum period in order to improve outcomes for both mother and child.”
Funding for this study was provided by National Institute on Drug Abuse (award number R25DA13582) and National Institute of Allergy and Infectious Disease (award AI052074-06A2).
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