This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti-Neoplastic Agents, Subject name: Pharmacology
[{'content': 'All of the following is true about hydroxyurea except: \nSelect and explain. \nA. Cause myelosuppression, B. Oral bioavailability is very less, C. Used in CM L, D. Act as radiosensitizer', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans: B (Oral...) HYDROXYUREA# Hydroxyurea is an analog of urea whose mechanism of action involves the inhibition of DAM synthesis by inhibiting the enzyme ribonucleotide reductase, resulting in depletion of deoxynucleoside triphosphate pools. This agent exerts its effects in the 5 phase of the cell cycle.The drug is administered orally and has nearly 100% oral bioavailability.It is mainly used in chronic myelogenous leukemia, blast crisis of acute myeloid leukemia , psoriasis & sickle cell anaemiaHowever, it is also effective as an adjunct with radiation therapy(as radiosensitizer) for head and neck cancer and in treating essential thrombocytosis and polycythemia vera.Myelosuppression is the dose-limiting toxicity, but nausea and vomiting, mucositis and diarrhea, headache and increased lethargy, and a maculopapular skin rash with pruritus are also observed.', 'role': 'assistant'}]