Can I donate blood honorably while taking Siofor 500 prescribed by an endocrinologist?

Most likely not, but the decision is made by the doctor qualifying for the donation. In most cases, health problems and taking medications are a contraindication to blood donation. I enclose an excerpt from the official NCK website regarding the question of whether it is possible to become a blood donor if you are taking any medications: "For the entire period of use of drugs (other than vitamins, oral contraceptives and hormonal drugs used during menopause) and for some time after stopping taking them, you should not donate blood. Always ask your donor doctor how long you need to wait after stopping the medicine, as the drugs have different periods of action." Source: https://www.gov.pl/web/nck/dyskwalifikacje It is not only about the possible presence of medicinal substances in the blood, but also about the donor, who must be in full strength and health to donate blood. I also attach our study on blood donation, perhaps it will be interesting: https://www.gdziepolek.pl/artykuly/honorowe-krwiodawstwo-czy-warto-oddawac-krew