Anne:

Re your question on using Phenobarbital (PB)  in a breastfeeding pair.

I have consulted with at least three physicians who used PB in their
breastfeeding mother.  In each case,  the plasma level in the infant was about
1/3 that of the mom.  We had a similar case in our clinics last year,  the mom
was fully breastfeeding and taking PB.  Her level was 15 ug/ml and the infants
was 5 ug/ml,  and had no untoward effects that our residents noted.

Of course you would want to be more cautious in weaken, or premature infants.
Phenobarbital is routinely used for neonatal seizures, so we have a long
history of its use in pediatrics.  Ask the physician to routinely monitor the
mom and infant for phenobarb plasma levels.  This should suffice.

Regards
Tom Hale