You can call Infant risk to get all the info on the drug directly and their opinion on it's safety in pregnancy and lactation. They may have a suggestion of another drug to try for your condition that would be safer in lactation
Dr Hale's book Medications and Mother's milk says (I will try to type it all out for you, ignore typos I'm typing with a cat in my lap)
Pramipexole is a nonergot dopamine agonist for use in treating the symptoms of Parkinson's disease and restless leg syndrome. While rodent studies showed rather high level sin milk, rat studies simply don't correlate with humans. No human studies are available concerning levels i milk.
Regardless, Pramipexole is known to reduce the secretion of Prolactin(the breastfeeding hormone) and it is possible that it could significantly reduce milk synthesis. This product should probably not be used in breastfeeding mothers.
Pregnancy risk C
Lactation risk L4(possibly hazardous)
the half life is 8 hours. [which means in 8 hours 1/2 of it remains in your system, in 16 hours 1/4 remains, in 24 hours 1/8 remains but then it's time for another dose.]
it peaks in 2 hours [so you would definitely avoid nursing for 2 hours or so after a dose.]
it is protein bound at 15% [you are lookig for drug with protein binding above 90%]
it is orally absorbed at 90% [so whatever enters breastmilk will be passed to baby orally]
its volume of distribution is 7.14 [the higher the volume of distribution, means the drug is stored around your body and takes longer to actually exit your system, not just it's blood half life above. you are looking for a volume of distribution <1]
the Molecular weight is 302 [the higher the molecular weight, the harder it is to enter breastmilk directly, if over 200 the drug has to dissolve the lipid bilayers in the mammary epithelium to enter milk. drugs that do not enter breastmilk at all have huge molecular weights like insulin with a MW >6000]
from the above info, I would recommend not taking the med and breastfeeding because even if the drug is safe for infant in the amounts that could enter breastmilk, the lowering of prolactin could mean an end to breastfeeding due to low/no milk supply.
so from the above chemical info about the dru