Dr. Hale, is quite correct, of course, in stating that it is not
guaranteed that a drug safe during pregnancy is also safe during
breastfeeding because during pregnancy the mother metabolizes and
excretes the drug for the baby.  It is nevertheless true that during
lactation, in general, the baby is exposed to *much less* drug, and at a
much less sensitive time in the baby's development.

But, for a drug such as sertraline (Zoloft) or paroxetine (Paxil) or any
other drug having significant effects on the central nervous system, the
issue is not only that of possible accumulation of the drug in the fetus
or newborn, but rather *any* exposure.  Those who oppose the use of
these drugs in breastfeeding women, point to the unknown longterm
effects of exposing the baby's developing nervous system to such drugs.
Of course we should be cautious and concerned, but when it is a question
of *any exposure*, I would say a drug which is safe during pregnancy
must be safe during lactation.  The question of accumulation is still
there, but if this is *not* an issue, the mother may be counselled that
she can continue breastfeeding.

I think there is now enough evidence that sertraline, given the risks of
formula feeding, can be used for breastfeeding mothers.  I also would
think that paroxetine could also be used for breastfeeding mothers,
though for reasons previously mentioned by Dr. Hale, I would hesitate to
suggest paroxetine for a pregnant woman.

Jack Newman, MD, FRCPC