Study finds domperidone not associated with severe mental health outcomes in new mothers

Recent case reports and media stories have emerged suggesting that people using domperidone, a drug commonly prescribed off-label to stimulate breast milk production, may be at risk of developing worrisome psychiatric symptoms, particularly when abruptly discontinuing the drug. New research published recently in Obstetrics & Gynecology has found no association between initiation of domperidone and an increased risk of new-onset psychosis or mental health diagnoses.

“Up until now, there have been little data on the link between domperidone and mental health concerns, beyond limited case reports and a recent Health Canada review of a small number of patients,” says lead author Jonathan Zipursky, a physician and scientist at Sunnybrook Health Sciences Centre and an assistant professor of medicine at the University of Toronto’s Temerty Faculty of Medicine.

“Given the number of people commonly prescribed the drug to help increase breast milk production, it’s important to explore its impact on a broader level.”

The retrospective study, led by researchers at Sunnybrook Research Institute, U of T and ICES, looked at postpartum individuals who gave birth between March 1, 2006, and March 1, 2022, in Ontario, Canada. Of the more than two million live births, 7,096 individuals filled prescriptions for domperidone within 56 days postpartum, according to the Ontario Drug benefits database.

Using publicly available data, the researchers analyzed how many of these patients were diagnosed with postpartum psychosis or mental health hospitalization in the year following birth, comparing them to a matched cohort that did not take domperidone. The research team — which included senior authors Tara Gomes and Mina Tadrous, both from U of T’s Leslie Dan Faculty of Pharmacy — found no differences among the groups.

While approved in Canada for treating gastrointestinal disorders, domperidone is often prescribed for its off-target clinical effects which impact the pituitary gland and stimulate the release of prolactin, consequently promoting lactation. While studies have shown that mothers taking domperidone only have a modest increase in breast milk production, domperidone is commonly prescribed, with its prevalence of use increasing over the past two decades.

“Our study found that use of domperidone postpartum does not appear to be associated with serious mental health outcomes," says Zipursky, also a scientist at ICES. “It is reassuring that no large-scale mental health effects were observed. However, clinicians should remain cautious and monitor patients for adverse outcomes including psychiatric symptoms.”

Zipursky adds that the study should not be seen as a safety endorsement of the drug, which has been linked to heart complications.

“Patients and clinicians should continue to balance the potential adverse effects of domperidone with its relatively modest benefit of increasing breast milk supply.”

This study was supported by ICES, the Ontario Ministry of Health and Ontario SPOR Support Unit.