An inhalant consisting of hyperoxic gas (95%-98% oxygen and 2%-5% carbon dioxide) with radiosensitizing properties. Inhaled carbogen reduces diffusion-limited tumor hypoxia, increasing tumor radiosensitivity due to the increased availability of molecular oxygen for cytotoxic radiation-induced oxygen free radical production. Check for active clinical trialsusing this agent. or A substance formed by the breakdown of protein in the liver. The kidneys filter carbamide out of the blood and into the urine. Carbamide can also be made in the laboratory. A topical form of carbamide is being studied in the treatment of hand-foot syndrome (pain, swelling, numbness, tingling, or redness of the hands or feet that may occur as a side effect of certain anticancer drugs). Also called urea.