Doxorubicin

Doxorubicin is an anthracycline antibiotic used as a chemotherapy agent. It exerts cytotoxic effects primarily by intercalating into DNA, inhibiting the enzyme topoisomerase II, and generating free radicals via iron-mediated reactions. These actions disrupt DNA replication and promote cell death in rapidly dividing cancer cells. In addition to the conventional formulation, a liposomal form of doxorubicin exists and is associated with different toxicity profiles.

Doxorubicin is used to treat a wide range of cancers, including breast cancer, various lymphomas, sarcomas, and leukemias, and is often part of combination regimens such as AC (doxorubicin and cyclophosphamide) and CHOP-like protocols. It is administered intravenously, typically every three weeks, with dosing based on body surface area. The drug is extensively distributed in body tissues and undergoes hepatic metabolism to an active metabolite (doxorubicinol), with renal and fecal excretion. Liposomal doxorubicin formulations can alter tissue distribution and toxicity.

Key safety considerations include cumulative cardiotoxicity, which can lead to congestive heart failure at higher total doses. Cardiac risk is influenced by dose, patient age, preexisting heart disease, and prior chest radiation. Baseline and periodic cardiac function assessment (eg, echocardiography or MUGA scans) are recommended. Dexrazoxane may be used as a cardioprotectant in select high-dose regimens. Other adverse effects include myelosuppression, nausea, mucositis, alopecia, and extravasation injury; red discoloration of urine and other secretions is common. Liposomal doxorubicin generally has reduced cardiotoxicity but can cause hand–foot syndrome and infusion reactions.