This class of drug induces tumor cell death by multiple mechanisms: 1) Doxorubicin inserts into the DNA of rapidly dividing cells, thereby inhibiting DNA synthesis; 2) Doxorubicin inhibits cellular enzymes such as topoisomerase I and II which are required from DNA replication and repair; 3) Doxorubicin also has the capacity to induce free radical/oxidative damage to cells ultimately leading to cell death.
Doxorubicin is administered IV every 2-3 weeks; side effects include those previously discussed (See Chemotherapy in Pets), including nausea, diarrhea, and bone marrow suppression, as well as potential damage to the heart muscle in dogs and renal tissue in cats. Doxorubicin cardiotoxicity can be either acute (reversible arrhythmias) or chronic (irreversible myocardial damage leading to DCM). This potential heart damage is primarily limited to large breed dogs and those predisposed to cardiac disease (Boxers, Doberman Pinschers, etc.). Also, because of the potential renal side effects in cats, doxorubicin is generally not used in cats with underlying kidney disease.
An additional side effect of this drug is that it can cause severe tissue damage if administered outside of the vein. For this reason, a perfectly placed catheter is required for each treatment. If even a minute amount of drug is leaked around the catheter site, the end result may necessitate aggressive wound management and in extreme cases, amputation. For this reason, only highly trained and experienced staff are allowed to administer this drug.
Despite these potential side effects, doxorubicin is still considered relatively safe and well tolerated by most pets. It remains the mainstay for treatment of multiple tumor types including lymphoma and various solid tumors.
For more information regarding Doxorubicin chemotherapy treatment and what we do to prevent problems, please click on the PDF logo.