poppie - the words "elbow" and "arse" come to mind when we are talking mv + bf 
Yes the two meds. are the same, just different brand names.
My mw said there was absolutley NOTHING I could take when I was badly constipated a few days after birth as I was bf. Load of rubbish I later found out after alot of unnecessary suffering !
It turns out very minute amounts of meds. get into the bm.
If in doubt about any meds, see kellymom.com for a full list of meds. said to be safe when bf by the American Academy of Paediatrics (AAP).
I have a copy of the list at hand and always take it to GP when I am ill, incase she prescribes something not on the list, I whip the list out !
My son is 20 months old now and because of this list I have been able to take cough meds, painkillers, sleeping tablets, you name it, while bf-ing him.
Actually I am appalled that the NHS does not have or give out such a list to ALL health profs. It seems to be bloody necessary as I am sure there are women who have given up bf simply because some moron told them to stop bf while taking meds.
Rant over