There is a search engine:
bil.aptek.pl
When you press "Leki w Polsce", you can find any medicine by its name. Whether it needs a prescription or not, it is stated in the column "Kat. dost." (category of accessibility): OTC ("over the counter", so without a prescription) or Rp ("recepta" - prescription).
The full list is available in this legal act:
dziennikmz.mz.gov.pl/DUM_MZ/2015/15/akt.pdf