Is Olanzapine safe while breastfeeding?

Effects on the breastfed infant

The manufacturer compiled reports of adverse effects reported in breastfed infants whose mothers were taking olanzapine.[ 15 ] Reports were compiled from spontaneous reports from physicians and mothers, clinical trials and published papers. Details of the exposures were not provided. Some of the infants reported appear to be the same as those reported in references [ 6 - 9 ] below. Overall, 102 breastfed infants were identified whose mothers were taking olanzapine. Of these, 62 reported dosages that averaged 7.4 mg daily by mouth taken during pregnancy. The duration of exposure to olanzapine was reported in 30 nursing mothers with a median of 30 days and mean of 74 days. Of the infants exposed to olanzapine via breastmilk, 15.6% reportedly experienced adverse effects, primarily somnolence, irritability, tremor and insomnia.[ 15 ] It appears that at least some of the adverse effects may have been a result of prenatal exposure to olanzapine. One infant was breastfed for 2 months during maternal intake of olanzapine 10 mg daily. No abnormalities were found in growth and development during 11 months of follow-up.[ 14 ] Five infants aged 3 weeks to 6 months were breastfed during maternal olanzapine 2.5 to 10 mg daily. No adverse health or developmental effects were noted during the observation period of 5 days to 8 weeks.[ 6 ] One infant was breastfed from birth during maternal use of olanzapine 5 mg daily orally. The infant was healthy at 6 months of age.[ 16 ] Six breastfed infants with an average age of 2.4 months (range 0.1 to 4.3 months) whose mothers were taking olanzapine 2.5 to 20 mg daily had no adverse effects reported by their mothers or found on detailed medical testing. Development was deemed normal in 4 infants after extensive testing. A fifth had a somewhat decreased intellectual development on testing, but her mother had also taken clonazepam, droperidol, sertraline, thioridazine and valproic acid while breastfeeding. Four of the infants' body weight were

Effects on milk supply

Unlike the phenothiazines, olanzapine has a minimal effect on serum prolactin levels.[ 22 - 26 ] However, olanzapine-induced hyperprolactinemia and galactorrhea have been reported.[ 27 ] One patient was also taking venlafaxine and interferon beta-1b which can increase serum prolactin; however, galactorrhea began only after olanzapine was started.[ 28 ] In 2 studies, some patients who were taking a conventional antipsychotic agent or risperidone had their medication changed to olanzapine. Previously elevated prolactin levels normalized, and galactorrhea diminished or stopped.[ 26 , 29 ] Patients enlisted in the National Pregnancy Registry for Atypical Antipsychotics who were taking a second-generation antipsychotic drug while breastfeeding (n = 576) were compared to control breastfeeding patients who had primarily diagnoses of major depressive disorder and anxiety disorders, most often treated with SSRI or SNRI antidepressants, but not with a second-generation antipsychotic (n = 818). Among women on a second-generation antipsychotic, 60.4% were on more than one psychotropic compared with 24.4% among women in the control group. Of the women on a second-generation antipsychotic, 59.3% reported ever breastfeeding compared to 88.2% of women in the control group. At 3 months postpartum, 23% of women on a second-generation antipsychotic were exclusively breastfeeding compared to 47% of women in the control group.[ 21 ] The number of women taking olanzapine was not reported. A single-center, retrospective cohort study over a 7-year period from January 2018 to January 2025 identified a total of 33 children aged 2 to 18 years who had drug-induced hyperprolactinemia. Risperidone was responsible for 27 of the cases. In all cases, prolactin levels normalized within a median time frame of 4 to 6 weeks after discontinuation of the drug or switching to an alternative medication.[ 30 ] A review of the FDA s FAERS database analyzed 6,195 reports of drug-induced galactorrhea in all pa

Levels in milk

Maternal Levels. A nursing mother started on olanzapine 20 mg daily on day 9 postpartum. Numerous milk olanzapine levels collected over the subsequent 8 days ranged from 7.6 to 27.5 mcg/L. The authors calculated that an exclusively breastfed infant would receive 0.011 mg/kg daily or about 4% of the maternal weight-adjusted dosage.[ 5 ] Nine paired serum and milk levels were obtained from 5 mothers who were taking olanzapine. In 2 women taking 10 mg daily, one had a milk level of 21 mcg/L 11 hours after the dose and the other had a milk level of 16 mcg/L 23 hours after the dose. In 3 women taking 2.5 mg daily, milk levels ranged from 1 to 8 mcg/L 11 to 12 hours after the dose, 4 mcg/L at 16 hours after the dose and 2 to 7 mcg/L at 22 to 23 hours after the dose. Using these data, an exclusively breastfed infant would consume an average of 1.6% of the maternal weight-adjusted dosage (range 0 to 2.66%).[ 6 ] Seven mother-infant pairs were studied during maternal olanzapine use. The mean dose was 7.5 mg daily (range 5 to 20 mg daily) and serum levels were at steady state. A median peak serum level of 16 mcg/L occurred 5.2 hours (range 0.7 to 13.2 hours) after the dose. The median infant dosage was 1.12% (range 0.22 to 1.19%) of the maternal weight-adjusted dosage in 6 of the mothers and 1.13% in the seventh.[ 7 ] A woman was taking olanzapine 5 mg orally 3 times daily, amounting to 270 mcg/kg daily. After 11 days on olanzapine, a milk sample was taken just before nursing (time after dose not reported). The concentration of olanzapine was 12 ng per gram of breastmilk. The authors estimated that was 0.3% of the maternal weight-adjusted dosage.[ 8 ] A woman was started on oral olanzapine 5 mg in the morning and 10 mg in the evening daily 3 months postpartum. Two weeks later, the milk concentration (time after dose not stated) was 5 mcg/L. Over a period of 5 months, milk olanzapine concentrations decreased somewhat with time and a reduction in dosage to a concentration of 3

Alternatives LactMed lists

• Quetiapine
• Lithium
• Quetiapine
• Risperidone
• Valproic Acid