Metronidazole: A Radiosensitiser of the Hypoxic Cells

The main reasons for the low radiosensitivity of bladder cancer especially in its advanced stages are the problems of necrosis, thrombosis and fibrosis producing large areas of hypoxic cells which are radioresistant. The employment of a drug which radiosensitise such cells offers great promise. Metronidazole (Flagyl) is a 5 nitroimidazole compound. It has shown a radiosensitising effect on hypoxic cells both in vitro and in vivo. This drug acts on the tumour, whereas it does not act on the normal tissues surrounding the growth. There is, therefore, no increased radiation damage on the normal tissues which are well vascularised and normally oxygenated. It acts particularly on the hypoxic cells of the tumour, which constitute its radioresistant cell subpopulation.