In general, any kind of decongestants can dry up some of your milk, so be aware of that. As far as Singulair goes, in just doing a minute of research just now, it looks like there haven't been any studies done on Singulair in breastfeeding moms, so it might be best to find an alternative. I agree that a pharmacist might be your best bet to ask this one. Good luck!
at 1:59 PM on Nov. 20, 2010