Doxorubicin
Doxorubicin Hydrochloride
Also known as: Doxil · Adriamycin RDF · Adriamycin PFS · Rubex · Caelyx · Myocet · cloridrato de doxorrubicina · doxorubicin hydrochloride liposome · doxorubicini hydrochloridum · liposomal doxorubicin hydrochloride · NSC-123127 · Hydroxydaunorubicin
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
This dose is based on body surface area (mg/m²). Convert body weight to body surface area before dosing.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Antineoplastic | 30 mg/m2 IV every 2-3 weeks | IV | every 2-3 weeks | — | 🌎 NA |
| Lymphoma, sarcomas, carcinomas | 30 mg/m2 (Use 1 mg/kg in dogs weighing <10 kg) | IV | q3wk | Maximum total cumulative dose not to exceed 240 mg/m2 | 🌍 EU |
- Antineoplastic: Depending on the protocol used. Maximum cumulative dose = 240 mg/m2.
- Lymphoma, sarcomas, carcinomas: Administer over a minimum of 10 minutes into side port of freely running 0.9% NaCl.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Antineoplastic | 20-30 mg/m2 IV every 2-4 weeks | IV | every 2-4 weeks | — | 🌎 NA |
| Lymphoma, soft tissue sarcomas | 1 mg/kg or 20-25 mg/m2 | IV | q3-5wk | Maximum total cumulative dose not to exceed 240 mg/m2 | 🌍 EU |
- Antineoplastic: Depending on the protocol used. Maximum cumulative dose is usually 240 mg/m2.
- Lymphoma, soft tissue sarcomas: Nephrotoxicity is a major risk in cats, especially at cumulative dosages >100 mg/m2.
Ferrets
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Antineoplastic | 30 mg/m2 IV every 3 weeks | IV | every 3 weeks | — | 🌎 NA |
- Antineoplastic: Depending on the protocol used.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Doxorubicin is an anthracycline glycoside antibiotic that is one of the most widely used antineoplastic agents in small animal veterinary oncology. Often referred to colloquially as the "Red Devil" due to its bright red color and potent side effect profile, it is utilized either as a single agent or within multi-drug combination protocols.
- Broad-Spectrum Efficacy: Highly effective against a variety of malignancies including lymphomas, carcinomas, leukemias, and sarcomas in both dogs and cats.
- Origin: Originally isolated from Streptomyces peucetius.
- Clinical Pearl: While it possesses antimicrobial properties, its profound cytotoxicity completely precludes its use as an anti-infective agent. It is a severe vesicant; extreme care must be taken to ensure clean intravenous access to prevent devastating extravasation injuries.
Mechanism of action
Doxorubicin is a cell-cycle non-specific cytotoxic agent with multiple mechanisms of action:
- Topoisomerase II Inhibition: Intercalates between DNA base pairs and inhibits topoisomerase II → prevents DNA resealing → causes double-strand DNA breaks → triggers apoptosis.
- Macromolecular Synthesis Inhibition: Directly inhibits DNA synthesis, DNA-dependent RNA synthesis, and protein synthesis.
- Free Radical Generation: Undergoes electron reduction to form anthracycline semiquinone free radicals (often iron-mediated) → causes severe oxidative stress and lipid peroxidation.
- Clinical Pearl: The heart is particularly susceptible to doxorubicin-induced oxidative damage because cardiac tissue has inherently low levels of catalase, an enzyme necessary to neutralize hydrogen peroxide. This is the primary mechanism behind its cumulative cardiotoxicity.
Safety & warnings
Contraindications
- Pre-existing severe myelosuppression
- Impaired cardiac function
- Patients who have reached the total cumulative dose limit of doxorubicin and/or daunorubicin
- Cats with pre-existing renal insufficiency
Adverse effects
- Bone marrow suppression (nadir 5-10 days)
- Cardiac toxicity (acute arrhythmias and cumulative cardiomyopathy)
- Nephrotoxicity (particularly in cats)
- Gastroenteritis (anorexia, vomiting, diarrhea)
- Alopecia
- Stomatitis
- Immediate hypersensitivity/anaphylaxis (primarily in dogs)
- Severe tissue ulceration and necrosis (if extravasated)
Precautions
WARNING: Severe Vesicant & Cardiotoxin
- Extravasation Risk: Doxorubicin is extremely irritating to tissues. Perivascular administration can cause severe tissue ulceration and necrosis. Must be administered IV slowly (over at least 10 minutes) via a perfectly placed, free-flowing catheter. If extravasation occurs, treat immediately (e.g., topical DMSO or IV dexrazoxane).
- Cardiotoxicity: Risk increases greatly when cumulative dose exceeds 240 mg/m2 in dogs (and likely cats). Breeds predisposed to cardiomyopathy (Dobermans, Great Danes, Rottweilers, Boxers) require extremely careful monitoring.
- MDR1/ABCB1 Mutation: Actively transported by p-glycoprotein. Dogs with MDR1 mutations (Collies, Australian Shepherds, etc.) are at high risk for severe toxicity. Dose reduction of 25-30% is recommended.
- Hypersensitivity: Immediate reactions (urticaria, facial swelling, hypotension) can occur, especially in dogs. Pretreatment with antihistamines (e.g., diphenhydramine) or dexamethasone is often recommended.
- Handling: Teratogenic and embryotoxic. Prepare in a biological safety cabinet. Wear gloves. Wash immediately if skin contact occurs.
Drug interactions
May potentiate the toxic effects of doxorubicin
Potentially could increase risk for cardiotoxicity associated with doxorubicin
Decreased carbamazepine levels
Increased risk of toxicity for both agents; carefully weigh risks versus benefits
May increase doxorubicin blood levels (AUC); doxorubicin may potentiate and prolong hematologic toxicity; coma and seizures have been reported in human patients
Can increase doxorubicin and doxorubicinol (active metabolite) levels
May reduce doxorubicin effectiveness; use together not recommended in humans
Doxorubicin may decrease phenytoin levels
May increase elimination and reduce blood levels of doxorubicin
May inhibit doxorubicin metabolism
May increase doxorubicin levels
Increased risk for bleeding
Increased risk for neutropenia
Increases plasma clearance of doxorubicin
Causes a reduction in serum digoxin levels
Incompatible in syringe/line; leads to precipitate formation
Incompatible in syringe/line; leads to precipitate formation
Incompatible in syringe/line; leads to precipitate formation
Increased risk of toxicity
Monitoring
- Efficacy of tumor response
- CBC with platelets (monitor for myelosuppression, nadir at 5-10 days)
- ECG and/or echocardiogram (especially in dogs with pre-existing heart disease or predisposed breeds)
- Hepatic function prior to and during therapy
- Urinalysis, serum creatinine, and BUN (especially in cats due to nephrotoxicity risk)
Pharmacokinetics
Half-life
Absorption
Not absorbed from the GI tract. Must be administered IV. Extremely irritating to tissues if administered SC or IM.
Distribution
Rapidly and widely distributed after IV injection. Does not appreciably enter the CSF. Highly bound to tissue and plasma proteins. Probably crosses the placenta and is distributed into milk.
Metabolism
Metabolized extensively by the liver and other tissues via aldo-keto reductase primarily to doxorubicinol, which is active; other inactive metabolites are also formed.
Elimination
Primarily excreted in the bile and feces. Only about 5% is excreted in the urine within 5 days of dosing. Eliminated in a triphasic manner.
Overdose
Inadvertent acute overdosage may be manifested by severe exacerbations of adverse effects (profound myelosuppression, severe GI toxicity, acute cardiotoxicity). A lethal dose for dogs has been reported as 72 mg/m2.
Treatment: Supportive and symptomatic therapy is required. Dexrazoxane may be useful to help prevent cardiac toxicity and should be considered in cases of massive overdose.
Available products
Formulations
- Lyophilized powder for injection
- Aqueous injection
- Liposomal injection
Human-labeled
- Doxorubicin HCl (Conventional) Lyophilized Powder for Injection: 10 mg, 20 mg, 50 mg, and 150 mg vials (Adriamycin RDF, generic)
- Doxorubicin HCl (Conventional) Injection (aqueous): 2 mg/mL in 5 mL, 10 mL, 25 mL, and 100 mL (Adriamycin PFS, generic)
- Doxorubicin, Liposomal Injection: 20 mg in 10 mL & 50 mg in 30 mL single-use vials (Doxil)
Regulatory status
POM (Prescription Only Medicine). Must be handled by trained personnel.
POM-V. Cytotoxic handling precautions apply.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Lyophilized powder: Store away from direct sunlight in a dry place. Reconstituted powder (with 0.9% NaCl) is stable for 24 hours at room temperature and 48 hours refrigerated. Aqueous injection: Stable for 18 months when refrigerated (2-8°C) and protected from light.
Client information
Important Information for Pet Owners Receiving Doxorubicin Therapy:
- Red Urine: Doxorubicin is red, and it is completely normal for your pet's urine to be colored orange to red for 1 to 2 days after treatment. This is not blood and is not harmful.
- Handling Waste Safely: The drug is excreted in your pet's waste. Avoid direct skin contact with urine or feces. Drug residues can be found in a treated dog's urine for up to 21 days and in feces for several days. Wear gloves when cleaning up accidents and wash hands thoroughly.
- Physical Contact: Do not allow your pet to lick human skin, especially the faces of children or immunocompromised individuals, while they are actively receiving chemotherapy.
- Expected Side Effects: Mild loss of appetite and occasional vomiting are common 2 to 5 days after therapy.
- When to Call the Vet: Contact your veterinarian immediately if your pet shows signs of profound depression, extreme lethargy, abnormal bleeding, bruising, or bloody diarrhea.
- Hair Loss: Some pets (especially certain dog breeds with continuously growing hair like Poodles or Terriers) may experience hair loss or thinning.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.