This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'A patient with cancer received extreme degree of radiation toxicity. Fuher history revealed that the dose adjustment of a paicular drug was missed during the course of radiotherapy. Which of the following drugs required a dose adjustment in that patient during radiotherapy in order to prevent radiation toxicity - \nSelect and explain. \nA. Vincristine, B. Dactinomycin, C. Cyclophosphamide, D. 6-Mercaptopurine', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Dactinomycin o The patient was most probably taking a radiosensitiser i.e., drugs which increases the toxicity due to radiotherpy. o The dose of these drugs should be decreased during radiotherapy o Among the drugs given in the question Actinomycin D or Dactinomycin is a radiosensitizer o Hypoxic cells are resistant to radiotherapy o Augmentation of oxygen is the basis of radiosensitization", 'role': 'assistant'}]