Dear Lactnet associates, Any discussion of antidepressant use in the bf'ing mother has to be tempered by the statement of the American Academy of Ped's Committee on Drugs published in Pediatrics Vol 93 pp.137-50 (1/94). In that article that Committee lists ALL antidepressant drugs in the category of "Drugs whose effect on nursing infants is unknown but may be of concern." It goes on to explain that "no case reports of adverse effects in bf'ing infants, these drugs do appear in human milk and this could *conceivably* alter short-term and long-term central nervous system funtion" Nontheless many physicians have successfully treated bf'ing mothers with antidepressants without apparent adverse effects on the infant. Certainly the older class of drugs, the tricyclic antidepressants such as nortriptyline (Pamelor and others) have the longest track record of apparent safety for bf'ing moms and their infants. (see also the input in this regard from Cindy Smith.) However this class of drugs has many side effects which limit usefulness. Newer drugs such as the selective serotonin reuptake inhibitors (SSRI's) such as Prozac (fluoxetine), Zoloft, Paxil and now others have been a great advance in the field of psychopharmacology because of their tolerability and perhaps more rapid onset of action. Before I forget, let me comment on some writers' concerns with messing with serotonin. Realize that serotonin is a neurotransmitter, BUT so is norepinephrine, dopamine, acetylcholine and others. All antidepressants affect one or another neurotransmitter. That is how they work! I am not aware of any greater need for concern when it comes to drugs that affect serotonin versus other neurotransmitters in the bf'ing mother. I certainly agree with the concern expressed by many writers here that with such a new drug class such as the SSRI's, we don't know the full ramifications of using it on bf'ing moms with PP depression. Nontheless there is at least one encouraging report published in Pediatrics which is worth quoting from. In a 1992 article (pp676-7), Kelly Burch and Barbara Wells, Pharm D's reviewed fluoxetine and norfluoxetine (the parent and major breakdown product of Prozac) concentrations in human milk. This study involved only one patient treated for PP depression begun 10 weeks post delivery. They found levels in the milk of 120 ng/ml which if the baby receives 150 ml/kg of milk per day produces a dose in the infant of 15-20 micrograms/kg per day. In other words in a 10 kg. baby, this would amount to ingesting 0.2 mg/day. Compare this to the 60 kg mother who is taking 20 mg. daily. Based on my calculations, this would lead to a dose in the mother of >300 micrograms/kg/day. In other words the baby is receiving less than 0.5% of the therapeutic dose on a weight for weight basis. Are you still with me? The authors go on to say that based on their measurements and calculations, combined with their observations of no adverse behavioral or developmental outcome in the baby, it may be reassuring to those who consider using Prozac as an alternative to traditional agents in lactationg mothers with PP depression. They go on to say that further work is needed before Prozac becomes a *preferred* agent in this situation. Let me clear up one other point. One of our participants on Lactnet state that Briggs 1994 edition describes Prozaac as contraindicated with bf'ing. MY 1994 volume of Briggs states no such thing (p. 375)! The only statement of concern in my volume of Briggs is that which I described in the opening of this letter--that of the American Academy of Peds where Prozac was lumped with all other antidepressants whose effects are unknown but may be of concern. As an internist, I have successfully ised nortriptyline for PP depression. I don't have any personal experience with prescribing Prozac for the bf'ing mother. Regarding Melissa's question, certainly one would expect that the exposure of a 3 year old to Prozac excreted in breastmilk would be much less than the younger child due to the fact that a 3 year old would be consuming a substantial amount of solid foods. Also one would expect that neurological development would be more advanced than in the younger child. Therefore there should be less concern. I certainly look forward to others' experiences and research in this area. Harry Chaikin, M.D.