Where can I buy it if I have a prescription?

As I understand it, it is about the tagged preparation Hexvix. Currently, pharmacies integrated with GdziePoLek do not have Hexvix in stock: https://www.gdziepolek.pl/produkty/35728/hexvix-proszek-do-wytworzenia-plynu/apteki/w-warszawie Hexvix is a drug intended only for diagnostics - detection of bladder cancer. The product stains abnormal cells of a possible tumor, which can be seen through a special instrument called a cystoscope. Due to the fact that it is a highly specialized preparation and intended for use by an experienced doctor, and not independently by the patient, it is unlikely to be available "on the spot" in any pharmacy. I would suggest asking in the selected facility about the possibility of ordering it from the wholesaler - if it is available, it is usually possible to process the prescription in the near future of placing the order.