methylene blue + fluorouracil

This is a combination drug consisting of methylene blue and fluorouracil. Methylene blue is a phenothiazine dye with multiple clinical uses, including the treatment of methemoglobinemia and as an antiseptic, while fluorouracil (5-fluorouracil or 5-FU) is a pyrimidine analog antimetabolite widely used as a chemotherapeutic agent for various cancers. The combination has been explored in pharmaceutical compositions for potential anti-tumor effects, with evidence suggesting that methylene blue may modulate the metabolism or activity of fluorouracil when used together[1][2][3]. Fluorouracil acts primarily by inhibiting thymidylate synthase and incorporating into RNA, leading to cytotoxicity in rapidly dividing cells[4]. Methylene blue has redox properties and can act on various cellular targets; it may also influence drug metabolism pathways.