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': "Which of the following can be given orally aEUR' \nSelect and explain. \nA. Cytosine ara, B. Actinomycin D, C. Doxorubicin, D. Mesna", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Mesna MESNA is given alongwith alkylating agents to prevent nephrotoxicity due to cyclophosphanzide. Cyclophosphamide and Ifosfamide are alkylating agents that release a nephrotoxic and urotoxic metabolite -> Acrolein. Acrolein causes severe hemorrhagic cystitis. MESNA is administered to prevent hemorrhagic cystitis. MESNA conjugates with Acrolein and forms a nontoxic compound. It can be administered intravenously or orally. Mesnex injection is given as intravenous bolus injection in a dosage equal to 20% of the ifosfamide dosage at the time of ifosfamide administration whereas Mesnex tablets are given orally in a dose equal to 40% of the Ifosfamide dose 2 and 6 hours after each dose of Ifosfamide. The total daily dose of mesna is 100% of the ifosfamide dose. Cytarabine Cytarabine (Ara C) is degraded by the enzyme cytidine deaminase. Cytidine deaminase is present in high concentrations in g.i. tract therefore only about 20% of the drug reaches the circulation after oral Ara-C administration. Thus the drug must be given intravenously. Dactinomycin or Actinomycin D It is administered by intravenous route. Doxorubicin It is administered intravenously and are cleared by complex pattern of hepatic metabolism and biliary excretion.', 'role': 'assistant'}]