Fluoxetine and breast feeding

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Editor, – We refer to the article 'Drug distribution in human milk' (Aust Prescr 1997;20:35-40) where breast milk transfer of maternal selective serotonin reuptake inhibitors (SSRIs) to the neonate is calculated for paroxetine, sertraline and fluoxetine (norfluoxetine). Infant doses are found to be 1.4%,0.67% and 6.3-13.9% of the mother's dose respectively. Under recommendations for breast feeding, paroxetine is considered 'probably safe', sertraline 'probably safe, but more data needed' and fluoxetine 'possibly safe, but more data needed'. It is the latter recommendation on which we wish to comment.

The Australian Adverse Drug Reactions Advisory Committee1 commented that breast milk transfer of maternal SSRIs to the breast-fed infant may be significant since 4 breast-fed infants experienced adverse reactions: one hyperglycaemia and glycosuria, two agitation, one somnolence. In two cases the mothers had been using sertraline, in one case fluoxetine and in one case paroxetine, but the doses or durations were not described.

The amount of fluoxetine ingested from breast milk is fairly high and the risk of accumulation in the breast-fed infant is important due to long half-lives of fluoxetine and active norfluoxetine. This is shown in the newly issued review from our department.2 Therapeutic concentrations of fluoxetine and norfluoxetine have only been demonstrated in one breast-fed infant with colic. The colic disappeared after discontinuation of fluoxetine treatment.3 A review by Wisner4 concludes that fluoxetine is not a first-line antidepressant because of adverse effects observed in infants with mothers using fluoxetine while lactating. Prescription of an antidepressant for a breast-feeding woman is a case-specific risk-benefit decision, and observation of the infant should be conducted. We are presently monitoring the situation in our ongoing study of SSRIs in pregnant and lactating mothers.

An interesting study was done on 84 women with postpartum depression where no difference in efficacy between fluoxetine and counseling therapy was seen.5 Maybe, on the whole, would a non-drug treatment be a better alternative for the infant?

Hedvig Nordeng and
Ingrid Matheson
Department of Pharmacotherapeutics
University of Oslo
Oslo, Norway