Analgesia in the Breastfeeding Patient

Giving a breastfeeding parent small, repeated doses of fentanyl (for example, 25 µg every five minutes to a maximum of 200 µg) or moderate doses of morphine generally adds only tiny amounts of opioid to mature breast milk. Fentanyl reaches its highest milk level roughly 45 minutes after a dose, falls by half within about two hours, and is usually below the limits of standard laboratory tests by six hours; the relative infant dose is far under 1 percent, and studies show no harmful effects on term infants (National Library of Medicine, 2024).

Morphine peaks 30–60 minutes after a dose and has a milk half-life near three hours. 

An example, with routine postoperative totals under 60 mg per day, the relative infant dose averages 2–3 percent, and careful infant observation is all that is required (National Library of Medicine, 2024). The Academy of Breastfeeding Medicine advises that most parents can nurse as soon as they are awake, stable, and alert; waiting one feed cycle (about three hours) after the last opioid dose provides an extra safety margin but is not essential if the baby is monitored for unusual drowsiness, weak suck, or slowed breathing (Academy of Breastfeeding Medicine, 2017)

References:

• National Library of Medicine. (2024, January 15). Fentanyl. In Drugs and Lactation Database (LactMed). National Institute of Child Health and Human Development. https://www.ncbi.nlm.nih.gov/books/NBK501222/

• National Library of Medicine. (2024, October 15). Morphine. In Drugs and Lactation Database (LactMed). National Institute of Child Health and Human Development. https://www.ncbi.nlm.nih.gov/books/NBK501237/

• Reece-Stremtan, S., Campos, M., Kokajko, L., Brodribb, W., Noble, L., Brent, N., … Academy of Breastfeeding Medicine. (2017). ABM clinical protocol #15: Analgesia and anesthesia for the breastfeeding mother (revised 2017). Breastfeeding Medicine, 12(9), 500–506. https://doi.org/10.1089/bfm.2017.29054.srt