Doxorubicin (Adriamycin)

Doxorubicin (Adriamycin): Uses, Dosage and Side Effects

Overview

• Inhibits DNA synthesis and function.

Uses of Doxorubicin (Adriamycin)

• Treatment of lymphoma, soft tissue sarcomas, osteosarcoma and haemangiosarcoma.
• May have a role in the management of carcinomas in the dog and soft tissue sarcomas in the cat.

Dose of Doxorubicin (Adriamycin) in Dogs and Cats

Dogs:

All uses:

• 30 mg/m2 i.v. q3wk. In dogs weighing <10 kg a dose of 1 mg/kg should be used.
• Maximum total dose not to exceed 240 mg/m2.

Cats:

All uses:

• 1 mg/kg or 20–25 mg/m2 i.v. q3–5wk.
• Maximum total dose not to exceed 240 mg/m2.

Side Effects of Doxorubicin (Adriamycin) in Dogs and Cats

• Acute anaphylactic reactions which require adrenaline, steroids, and fluids.
• Doxorubicin dose-dependently causes cardiomyopathy and congestive heart failure in dogs.
• >240 mg/m2 increases cardiotoxicity risk. Monitor for tachycardia, arrhythmias, and clinical exam/auscultation.
• Anorexia, vomiting, severe leucopenia, thrombocytopenia, haemorrhagic gastroenteritis, and nephrotoxicity (in cats at >100 mg/m2) are the main side effects.
• Treatment should be halted if neutrophil or platelet counts fall below 2.5 or 50 109/l.
• After counts stabilise, restart doxorubicin at the same dose. Recurring haematological or GI toxicity requires a 10–25% dose reduction.
• Perivascular extravasation injuries can cause tissue necrosis and ulceration. Ice compresses (15 min q6h) may help.
• Dogs with the ABCB1 (MDR1) mutation may be at higher risk of toxicity.

Contraindications of Doxorubicin (Adriamycin) in Dogs and Cats

• Do not use in patients with existing cardiac disease.
• Do not use in cats with renal disease/dysfunction.

Some Notes:

• Barbiturates increase plasma clearance of doxorubicin.
• Concurrent administration with cyclophosphamide increases the risk of nephrotoxicity in cats.
• The agent causes a reduction in serum digoxin levels.
• Do not mix doxorubicin with other drugs.
• Doxorubicin is incompatible with dexamethasone, 5-fluorouracil and heparin; concurrent use will lead to precipitate formation.
• Do not use with spinosad: increased risk of toxicity.