I completely understand about the worries over being told something "should" be OK. There is a well worked out system for comparing the safety measures for various drugs: L1 is "safe" L2 "safer" L3 the benefits may exceed the risks etc; you can search the database here:
http://neonatal.ttuhsc.edu/cgi-bin/d...s&access=guest
A drug may or may not enter your milk. If it enters your milk, then it may or may not be capable of being absorbed by the baby's GI tract. If it is metabolised by the baby, then it may or may not be excretable by the baby - if it is excreted then the amount shouldn't build up in baby. You can also check to see if the drug is licensed for children - if so, it's less of a concern.
In any case, the risks of taking the drug have to be balanced against the well-established risks of either not taking the drug or of switching to formula.
The AAP comments at
http://www.aafp.org/afp/20010701/119.html : Maternal depression is known to have an adverse effect on parenting and infant development.14 Tricyclic antidepressants have been shown to have little to no effect on the breast-feeding infant, although the AAP finds most tricyclic agents to be of possible concern.3,7 Taking a single daily dose at bedtime will limit the infant's exposure to the medication. The selective serotonin reuptake inhibitors (SSRIs) are generally the first choice of treatment for depression. Sertraline (Zoloft) is likely to be the safest choice among them because it has been studied extensively and because drug levels found in nursing infants are usually minimal.7,12
HTH
Melanie
