If you are breastfeeding and looking for a medication to help with nasal congestion, you can consider using oral decongestants like pseudoephedrine found in Tylenol Sinus or Advil Sinus. However, it is important to note that these medications may decrease milk production by up to 24%. Another option to consider is using a nasal spray decongestant like Drixoral or Otrivin, which act locally in the nose and do not affect milk production. It is recommended to limit the use of nasal decongestants to 7 days to avoid rebound congestion.