A client whose baby was diagnosed "lactose intolerant" and told to use soy
opted instead to use lactase drops.  She gave the baby drops directly -
more than the company recommended - and it worked.  I'm sure the extra
drops were because human milk is markedly higher in lactose than the milks
the company usually deals with, and perhaps also because they didn't work
as effectively when used directly.

She found that her baby's stomach was most settled on the several days a
week on which she worked part-time.  On those days, the baby got expressed
milk that had had drops added the night before, so the lactose was really
well broken down.

For the baby in real trouble, I suppose a few days of expressed and
pre-treated milk followed by a resumption of nursing with drops (and, of
course, one-sided nursing) might work.

Diane Wiessinger, MS, IBCLC, LLLL  Ithaca, NY