(163) Assessment of dextromethorphan concentration in human breast milk

Thursday, February 9, 2023

10:30 AM – 12:00 PM

Objective: Dextromethorphan (DM) is an adjunct to the regimen for the Enhanced Recovery After Surgery protocol for patients undergoing cesarean section to improve analgesia and limit opiate use. However, studies evaluating the risks of DM and breastfeeding are lacking. Our primary objective is to quantify DM and the active metabolite, dextrorphan (DX), in human milk among DM users during the first days postpartum. Our secondary objective is to determine neonatal plasma concentrations.

Study Design: In this pilot study at a community hospital from January 2021 to February 2022, women were recruited among those who (a) planned a full-term cesarean section, (b) use the DM containing ERAS protocol, and (c) breastfeed. Maternal blood, maternal breast milk, and neonatal blood were collected at specified times close to the predetermined drug steady state. The samples were analyzed with liquid chromatography mass spectrometry. Our null hypothesis is that the infant is exposed to important dextromethorphan concentrations, defined as a Relative Infant Dose (RID) > 10%.

Results: Fifteen volunteers and their neonates met criteria for inclusion, 8 of which were able to produce adequate milk for analysis. At steady state, 4-6 hours after the third dose of DM, we calculated a median milk to plasma ratio (M/P) of 3.290 for DM and 4.325 for DX. Using M/P, we calculated the median estimated RID to be 0.239% for DM and 0.288% for DX. DM was detectable with concentrations greater than the lower limit of quantification in a single neonatal blood specimen for a single subject where maternal DM concentration was substantially higher than the mean for the group.

Conclusion: DM and DX are detectable in milk from study subjects while the RID were below the target levels for the neonate. This pilot study supports the likelihood that dextromethorphan is a safe alternative to opioid pain medication in a breastfeeding mother as it appears that the RID is substantially lower than 10% and neonatal plasma concentrations were generally low or undetected. Future study is warranted to evaluate the effects on the newborn over time.

Primary & Presenting Author(s)

Daniel Lieberman, MD (he/him/his)
Cooperman Barnabas Medical Center
Livingston, New Jersey, United States

Coauthor(s)
DO
Devon O'Brien, MD
Maternal-Fetal Medicine Fellow
University of Missouri-Kansas City
Kansas City, Missouri, United States

RM
Rachel Meyers, Pharm D
Rutgers, The State University of New Jersey
Livingston, New Jersey, United States

LG
Lauren Gottshall, MD
Cooperman Barnabas Medical Center
Livingston, New Jersey, United States

CY
Christine Yohn, PhD
Ernest Mario School of Pharmacy
Piscataway, New Jersey, United States

AS
Anna Siemiątkowska, N/A
Poznan University of Medical Sciences
Piscataway, New Jersey, United States

KK
Katarzyna Kosicka-Noworsyn, N/A
Poznan University of Medical Sciences
Piscataway, New Jersey, United States

MK
Marta Karaźniewicz-Łada, N/A
Poznan University of Medical Sciences
Piscataway, New Jersey, United States

LB
Luigi Brunetti, PhD
Ernest Mario School of Pharmacy
Piscataway, New Jersey, United States

LK
Leonid Kagan, PhD
Ernest Mario School of Pharmacy
Piscataway, New Jersey, United States

RM
Richard C. Miller, MD
Cooperman Barnabas Medical Center
Livingston, New Jersey, United States