The manufacturers  of Maxolon (UK brand of metoclop) sent me a pile of papers
on use to increase prolactin, mainly from Scandinavian research, including
levels in milk and safety.

It does seem to help when mothers supply solely from pumping begins to
diminish if baby cant go to breast. Some women may develop side effects and
the highest incidence of these s/e tends to be in young adult women. Hence
less often prescribed for nausea than domperidone.

As it is not licensed to increase prolactin, prescriber has to bear
responsibility - or at least share it with fully informed mother.

Having said all that I took it with my third with sudden and rapid increase in
milk and no side effects.

Wendy Jones
Breastfeeding Network (UK) and Pharmacist