<prompt> Characteristic toxicity of daxorubicin -Pulmonary fibrosisCardiotoxicityPeripheral neuropathyHemorrhagic cystitis  <response>: Ans. is b i.e., Cardiotoxicity Anthracvclineso Anthracyclines are anticancer antibiotics and they include Doxorubicin Adriamycin and Daunorubicin.o The major toxicity of anthracyclines is potentially irreversible cumulative dose related toxicityo They may causes arrhythmias and cardiomyopathy. Because of their carditoxicity these drugs should be avoided in the patient with MI and CHF.o The antracyclines exert their anticancer activity through four major mechanisms -1. Inhibition of topoisomerase II2. Blockade of synthesis of DNA RNA, and DNA strand scission.3. Alter fluidity and ion transport.4. Generation of semiquinone free radicals and oxygen free radicals - this free radical mechanism is the cause of cardiotoxicity.o This cardiootoxicity can be prevented by using dexrazoxane a free radical scavenger and a-tocopherol.o Liposomal forms of these drugs also reduce cardiac toxicity.o Adverse effects - Dose related myelosuppression with neutropenia, dose limiting mucositis, cardiotoxicity AI 96, 94, AIIMS 93o Uses of Doxorubicin Ca Breast Ca Endometrium Ca ovary Ca testicle Ca thyroid Ca lung Hodgkin s disease Non Hodgkin disease Sarcomaso Uses of Daunorubicin It has far narrower spectrum of activity than Doxorubicin It is mainly used in acute leukemia. 