Which of the following can be given orally aEUR': (A) Cytosine ara, (B) Actinomycin D, (C) Doxorubicin, (D) Mesna
Answer is D. 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.