Vinblastine
Vinblastine is a **Vinca alkaloid antineoplastic agent** derived from the periwinkle plant (*Cantharanthus roseus*). It is primarily utilized in veterinary oncology for the treatment of various malignancies in small animals, including lymphomas, carcinomas, mastocytomas, and splenic tumors. **Clinical Pearls:** * Vinblastine is notably more effective than its close relative, vincristine, in the treatment of **canine mast cell tumors**. * It is a potent **vesicant**; extravasation outside the vein can cause severe tissue necrosis and cellulitis. * It is generally more myelosuppressive than vincristine, but tends to have less severe peripheral neurotoxic effects at standard doses. * Caution is highly warranted in herding breeds with the **MDR1 (ABCB1) mutation**, as they are at significantly increased risk for severe bone marrow suppression and gastrointestinal toxicity.
Mecanismo: Vinblastine is a cell-cycle specific agent that halts cell division. * **Microtubule Inhibition:** It binds specifically to **microtubular proteins (tubulin)** in the mitotic spindle. * **Mitotic Arrest:** By preventing microtubule assembly, it arrests cell division during **metaphase**. * **Metabolic Interference:** It also interferes with amino acid metabolism by inhibiting glutamic acid utilization and preventing purine synthesis, the citric acid cycle, and urea formation.
Dosificación por especie
- Susceptible neoplasms · 2-2.2 mg/m2 · IV · every 1-2 weeks · Often used in combination with other chemo drugs.
- Susceptible neoplasms (e.g., mast cell tumors, lymphoma) · 2-2.2 mg/m2 · IV · every 1-2 weeks · Often used in combination with other chemo drugs (e.g., cyclophosphamide and prednisolone).
- Mast cell tumors (specific protocol) · Given on four subsequent days · IV · every 3 weeks · Consult specialized oncology references for exact protocol details.
Las dosis son una referencia clínica para médicos veterinarios. Confirme siempre con la información vigente del producto y el paciente individual.
Vías de administración
Contraindicaciones
- Preexisting leukopenia or granulocytopenia (unless caused by the disease being treated)
- Active bacterial infection
- Neutrophil count < 3 x 10^9/L
- Platelet count < 100 x 10^9/L
- Pre-existing severe myelosuppression or active infection
- Pre-existing severe myelosuppression (Neutrophil count < 3 x 10^9/L or Platelet count < 100 x 10^9/L)
Efectos adversos
- Gastroenterocolitis (nausea, vomiting, anorexia)
- Myelosuppression (neutropenia, thrombocytopenia, anemia; nadir at 4-9 days)
- Neurotoxicity (constipation, paralytic ileus, jaw and muscle pain, loss of deep tendon reflexes)
- Alopecia
- Stomatitis
- Syndrome of inappropriate ADH secretion (SIADH)
- Severe tissue irritation and cellulitis (if extravasated)
- Cats: Reversible axon swelling and paranodal demyelination
- Myelosuppression (primarily neutropenia)
- Gastrointestinal toxicity (vomiting, diarrhea, anorexia)
- Severe tissue necrosis (if extravasated)
- Myelosuppression (neutropenia, thrombocytopenia)
- Gastrointestinal toxicity
Interacciones farmacológicas
- Cisplatin · May cause additive risk for ototoxicity.
- Carboplatin · May cause additive risk for ototoxicity.
- P-glycoprotein inhibitors (e.g., Amiodarone, Ketoconazole, Cyclosporine, Diltiazem, Erythromycin, Spironolactone, Verapamil) · Can inhibit P-glycoprotein clearance of vinblastine, increasing the risk of severe toxicity, particularly in dogs with the MDR1 (ABCB1) mutation.
- Cimetidine · Inhibits hepatic cytochrome P450 enzymes, potentially decreasing vinblastine metabolism and increasing toxicity. · major
- Other myelosuppressive agents · Additive bone marrow suppression. · major
Monitoreo
- Efficacy (tumor response)
- Complete blood counts (CBC) with platelets (monitor for nadir)
- Liver function tests (prior to therapy and repeated as necessary)
- Serum uric acid
- IV site for signs of extravasation during administration
- Haematology (CBC) prior to each treatment
- Biochemistry prior to first treatment
- Tumour restaging (lymph node palpation, cytology)
- Complete Blood Count (CBC) prior to every dose (specifically neutrophils and platelets)
- Tumor restaging at week 4 and week 12 (for high-risk tumors)
- IV catheter site for signs of extravasation during administration
Sobredosis
The lethal dose in dogs is reported as **0.2 mg/kg**. **Clinical Signs of Overdose:** Exacerbation of adverse effects, including profound myelosuppression, severe gastrointestinal signs, and neurotoxicity (similar to vincristine). * *Feline Case Report (4X IV overdose):* Depression, inability to jump, anorexia (days 1-11), neutropenia with fever, thrombocytopenia, anemia, vomiting, diarrhea, and syndrome of inappropriate ADH (SIADH). **Treatment:** Aggressive supportive care is required. Monitor cardiovascular and hematologic status closely. Treatment may include anticonvulsants, prevention/management of ileus, and management of SIADH (fluid restriction and loop diuretics to maintain serum osmolality).
La referencia de fármacos de VetSheet está destinada a médicos veterinarios como apoyo a la decisión clínica; no sustituye el juicio profesional ni la información vigente del fabricante.