Hello Lactnetters! My name is Amy Knutson, and I am another nursing student at the University of North Dakota.  I am writing in response to a post by Jill Meltzer that presented the question, “Does anybody have any new information or experience with mothers’ breastfeeding while on Prozac?”  While digging through the archives, I found that Prozac has been discussed off and on in the last couple of years, but peoples’ opinions regarding the issue have varied greatly. In reviewing the literature, I have found the following information:

Chambers, et al. (1999), studied a group of 64 women identified through the California Teratogen Information Service and Clinical Research Program, to examine weight gain in infants who were breastfed by mothers who took Prozac/Fluoxetine and compared them to infants of mothers who did not take Prozac or any other psychotherapeutic medication.  Postnatal weight gain was recorded from the infant’s pediatric records.  It was also the intent of the study to assess the frequency of side effects in infants breastfed by mothers taking Prozac.  These side effects were measured by the mothers’ responses to an interview questionnaire. Twenty-six of these women continued to take Prozac while breastfeeding, the other 38 did not take the medication.  Those women eligible for the study had to breastfeed their infants exclusively for two weeks or more after a full term delivery.  Maternal dose of Prozac measured between 20mg –40 mg a day. Researchers reported that infants breastfed by mot
hers taking Prozac had an average deficit of 392 grams when two measurements were taken between 2 weeks and 6 months of age. Mothers taking Prozac while breastfeeding did not report any unusual symptoms as evidenced by the questionnaire.  The researchers of the study concluded that while there was no excess of infants (breastfed while on Prozac) who were more than 2 standard deviations below the mean, this reduced growth may be significant in situations where the infants’ weight gain is already a concern. Other maternal variables tested included maternal age, ethnic group, socioeconomic status, parity, prepregnancy weigh and height, CES-D score, and use of tobacco. Characteristics of mothers and infants in the control and variable groups were similar other than the use of Prozac. Infant variables included gestational age and admission to a special care nursery. In the final model of study, no variable was retained as a significant risk factor. Most of the Prozac-breastfed inf
ants were exposed the longest to Prozac in utero as well as postnatally.  An adjustment was made in the measurement model for the effect of birth weight, however:

“the effect on postnatal growth could be of prenatal onset.  The sample size is insufficient to address this question adequately…among infants whose mothers breastfed without using fluoxetine, postnatal weight gain was similar in those whose mothers had used the drug latest in pregnancy, compared with those whose mothers had discontinued use of fluoxetine before the third trimester…This suggest that postnatal growth deficits are not entirely attributable to prenatal exposure to the medication,” (Chambers, et al., 1999).

Another study, done by Kristensen, et al. (1999) studied the percentage of maternal dose of Fluoxetine and it’s metabolite, Norfluoxetine, that the infant is exposed to, via breastmilk.  Kristensen et al. (1999), studied 14 breastfeeding women whose median dose of fluoxetine was .51 mg/kg/day , representing an absolute dose of 20-80 mg/day. Breast milk samples, maternal venous blood, and fetal venous blood were all examined by high performance liquid chromatography.  All of the infants were exposed to fluoxetine in utero. Mothers were also interviewed regarding side effects of their breastfed infants.  The mean infant exposure was reported as 6.8% of the maternal dose (fluoxetine plus norfluoxetine).  All of the infants had normal body weights.  Two were described by the mothers as having colic.  Two of the infants were referred to the study because of their symptoms of withdrawal (one of these infants was also exposed to maternal methadone, which may have contributed). Thes
e two infants had high values of infant dose via breastmilk.  Eight of the fourteen infants were described as having no adverse effects, (Kristensen et al., 1999).

Hendrick, et al. (2001) in a study of 20 infants (one pair of dizygotic twins) and 19 breastfeeding mothers found that “Among the group of infants whose mothers were on 30 mg of fluoxetine or higher, the mean infant serum concentration of norfluoxetine was significantly higher than it was for the group of infants whose mothers were on 20 mg or less,” (Hendrick et al., 2001). Infants’ ages and weights did not affect their serum concentrations.  When mothers were questioned about other possible side effects, none were reported.  In breastfeeding mothers taking a dose of Prozac at 20 mg/day or lower, drug concentrations were typically nondetectable or very low. Where as 30 mg/day or higher was significantly more likely to be detected in the infants’ serum.  Hendrick, et al. (2001) also found that breastmilk concentrations were highest 8 hours after the mothers’ ingestion of Prozac.  Hendrick et al.(2001) goes on to state that “In the absence of adverse effects in the infant, th
ere is no clear reason for a woman to discontinue nursing regardless of the infant’s serum concentration…we believe that breast-feeding is not absolutely contraindicated for women who continue to use fluoxetine.”

I hope this is helpful for those of you seeking information regarding the use of Prozac while breastfeeding.  Any feedback would be greatly appreciated!

Amy Knutson, Student Nurse
University of North Dakota

References

        Chambers, C.D., Anderson, P.O., Thomas, R.G., Dick, L.M., Felix, R.J., Johnson, K.A., Jones, K.L Weight gain in infants breastfed by mother who take fluoxetine. Pediatrics. 1999; 104 :61 [PubMed].

        Hendrick, V., Stowe, Z.N., Altshuler, L.L., Mintz, J., Hwang, S., Hostetter, A., Suri, R., Leight, K., Fukuchi, A., Fluoxetine and norfluoxetine concentrations in nursing infants and breast milk. Biological psychiatry. 2001; 50 775-782 [PubMed].

        Kristensen, J.H., Ilett, K.F., Hackett, L.P., Yapp, P., Paech, M. & Begg, E.J., Distribution and excretion of fluoxetine and norfluoxetine in human milk. Br J Clin Pharmacol. 1999; 48: 521-527 [PubMed].

             ***********************************************

To temporarily stop your subscription: set lactnet nomail
To start it again: set lactnet mail (or digest)
To unsubscribe: unsubscribe lactnet
All commands go to [log in to unmask]

The LACTNET mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software together with L-Soft's LSMTP(TM)
mailer for lightning fast mail delivery. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html