1. Clinical Overview
Vinblastine is a vinca alkaloid antineoplastic agent derived from the periwinkle plant, Catharanthus roseus. It is primarily used in the treatment of various cancers, most notably Hodgkin's lymphoma and other lymphomas, as well as testicular cancer, breast cancer, and Kaposi's sarcoma. It is a cell cycle-specific agent that binds to tubulin, inhibiting microtubule formation.
| Onset | Duration | Bioavailability |
|---|---|---|
| NA | NA | NA |
2. Mechanism of Action
Vinblastine sulfate binds with high affinity to the beta-subunit of tubulin dimers at a distinct region (the vinca domain). This binding inhibits the polymerization of tubulin into microtubules, thereby preventing the assembly of the mitotic spindle. The disruption of the microtubule dynamics arrests cell division at the metaphase/anaphase junction (M-phase of the cell cycle). It also interferes with other microtubule-dependent functions such as axonal transport and secretion.
3. Indications & Uses
- Hodgkin's lymphoma (part of combination regimens like ABVD)
- Non-Hodgkin's lymphomas
- Advanced testicular germ cell tumors
- Advanced breast cancer
- Kaposi's sarcoma
- Histiocytosis X (Langerhans cell histiocytosis)
- Choriocarcinoma (resistant to other therapy)
4. Dosage & Administration
Adult Dosage: Typically 3.7-6 mg/m² (up to 18.5 mg/m² in some regimens) administered intravenously every 7-14 days. Dose is highly regimen and indication specific and must be adjusted based on blood counts.
Administration: For INTRAVENOUS USE ONLY. Must be administered as a slow intravenous push or brief infusion (usually over 1 minute to 10 minutes) into the side port of a free-flowing IV line. Extreme care must be taken to avoid extravasation, which can cause severe tissue necrosis. The solution is a vesicant.
5. Side Effects
Common side effects may include:
- Bone marrow suppression (dose-limiting toxicity), especially leukopenia and neutropenia
- Nausea and vomiting (usually mild to moderate)
- Alopecia (hair loss)
- Constipation (due to neurotoxicity affecting autonomic nerves)
- Peripheral neuropathy (numbness, tingling, loss of deep tendon reflexes)
- Mucositis/stomatitis
- Fatigue
- Local tissue damage and phlebitis if extravasated
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Phenytoin | Vinblastine may decrease phenytoin levels, reducing its anticonvulsant effect. | Major |
| Erythromycin, Itraconazole, other CYP3A4 inhibitors | May increase vinblastine plasma concentrations and toxicity (especially neurotoxicity and myelosuppression) by inhibiting its metabolism. | Major |
| Mitomycin-C | Increased risk of pulmonary toxicity (acute bronchospasm, dyspnea). | Major |
| Other Myelosuppressive Agents (e.g., other chemotherapies, clozapine) | Additive bone marrow suppression. | Major |
| Live Vaccines | Risk of disseminated infection due to immunosuppression. | Major |
7. Patient Counselling
8. Toxicology & Storage
Overdose: Seek immediate medical attention.
Storage: Store in a cool, dry place.