Dacarbazine
Dacarbazine is used in veterinary medicine for rescue chemotherapy for melanoma and lymphoreticular neoplasia.
Group
Antineoplastic alkylating agent
Mechanism of Action
Hepatic activation generates cytotoxic metabolites that damage nucleic acids.
Dose Rates
Dog
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Chemotherapy | Reference only | IV | Body-surface-area protocols: 200 mg/m² daily for 5 days, repeated every 3 weeks; alternatively 800–1000 mg/m² every 3 weeks. These are distinct protocols and require BSA calculation. | |
| Alternative chemotherapy infusion | Reference only | IV | 800–1000 mg/m² infused over 5–8 hours, repeated every 2–3 weeks. Body-surface-area protocol; not mg/kg. |
Indications
- Rescue chemotherapy for melanoma and lymphoreticular neoplasia
Contraindications
- Cats
- Food-producing animals
- Hypersensitivity to dacarbazine
- Use cautiously with pre-existing marrow suppression, hepatic or renal dysfunction, or active infection.
Interactions
- Other marrow-suppressing medicines can increase hematologic toxicity.
- Rifampin, phenobarbital and phenytoin may increase metabolism; the clinical effect requires assessment.
Adverse effects
- Leukopenia
- Nausea, vomiting and diarrhea
- Thrombocytopenia and delayed marrow toxicity
- Extravasation injury, venous spasm and phlebitis
- Rare severe hepatic injury, renal impairment and photosensitivity
Toxicity
Myelosuppression and gastrointestinal injury limit dosing.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| DTIC 200 mg vial | Injection | 200 mg / vial | IV |
Monitoring and Administration
Monitor CBC before treatment and during marrow recovery.
Protect the vial from light. Dilute the prescribed dose in 50–100 mL of 0.9% saline; use a defined oncology protocol.
Include differential leukocyte and platelet counts, renal and hepatic testing during treatment; marrow nadirs can be delayed for weeks.
Use cytotoxic-drug handling precautions during preparation, administration and waste disposal. Avoid extravasation; concentrated injection can be painful.
Reconstitution stability depends on the exact presentation. The additional source describes up to 72 hours refrigerated or 8 hours at room temperature after sterile-water reconstitution; further diluted saline/D5W solution up to 24 hours refrigerated or 8 hours at room temperature. Confirm the actual vial instructions before applying these periods.