Judy Knopf--  Metaclopramide (in US "Reglan") is a drug
that is used to support a limited milk supply and is used
in relactation and induced lactation.  It works by
"inhibition of hypothalamic prolactin inhibiting
factor through dopamine antagonism" per Ruth Lawrence
1995 p.559.  It's actually a GI med, but we use it for
it's side effect impact of increased prolactin.

My own experience in using it has almost
exclusively been with moms of premies who are faced
with dwindling supply as they pump long periods before
being able to put baby to breast.  We've had fairly
good results but find that we must do ongoing dose
(rather than taper off) until baby is going to breast.
Of course the stimulation must be continued, too.

Let me know if you need specific references or dosing.