Olanzapine Relatively Safe During Breast-Feeding


Laurie Barclay, MD


Aug. 8, 2003 — Only a small amount of olanzapine transfers from mother to
baby during breast-feeding, according to the results of a small trial
published in the August issue of the American Journal of Psychiatry. The
investigators suggest that it is relatively safe to breast-feed while
taking this medication but that mothers should avoid doing so during the
peak levels achieved within five hours postdose.

"The incidence of psychiatric disorders is at its peak during the
postpartum period, with up to 20% of mothers affected," write Sharon J.
Gardiner, MClinPharm, from Christchurch Hospital in New Zealand, and
colleagues. "The use of olanzapine in the treatment of postpartum psychosis
has been limited by sparse data on its transfer into breast milk and on the
effects of exposure to the drug on a suckling infant."

In seven mother-infant nursing pairs, high-performance liquid
chromatography revealed that the median infant dose of olanzapine ingested
through milk was 1.02% of the maternal dose. Maximum relative infant dose
was approximately 1.2%. The authors point out that these ratios are much
lower than the national cutoff of 10.0% used to guide drug safety during
breast-feeding.

In six patients with data collected over the dose interval, the median milk-
to-plasma area-under-the-curve ratio was 0.38. Six infants with an
evaluable plasma sample had undetectable levels of olanzapine. All of the
infants were healthy and had no apparent adverse events.

"These data support the use of olanzapine during breast-feeding," the
authors write. "However, the authors recommend that breast-fed infants be
monitored closely and the decision to breast-feed be made after individual
risk-benefit analysis."

The Women and Infants Research Foundation in Subiaco, Western Australia,
helped fund this study.

Am J Psychiatry. 2003;160:1428-1431

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