Antihistamines have anecdotally been associated with a decreased milk
supply.  There is no proof, and the basis of this decrease is a little
difficult to figure, but there is the nagging occasional story that
makes one wonder.

Though progestin only pills are not supposed to cause problems with milk
supply, and there are studies to back this up, there are still some
questions that they may.  Certainly when they are used early, they could
very well interfere with the milk supply.  It is the *drop* in
progesterone in the first few days after delivery of the placenta which
results in the alveolar cells of the breast becoming sensitized to
prolactin and producing larger amounts of milk.  It is for this reason
that many physicians' prescribing depo-provera or pills before discharge
from hospital after delivery should be curtailed.

I do not think any of the other medications would make a difference.

There can be other reasons for a decreased milk supply besides
medication, despite the mothers success with twins.

If you are not in the US, you can increase the mother's milk supply with
domperidone 20 mg qid.  This works quite well.  If you are in the US,
domperidone is like metoclopramide, but has many fewer side effects.  I
would not prescribe metoclopramide, but would use fenugreek and blessed
thistle if I did not have domperidone available.

Jack Newman, MD, FRCPC