Members: Vincristine, Vinblastine, Vinorelbine, Vindesine
Class: Plant alkaloids (derived from Catharanthus roseus / Madagascar periwinkle).
Mechanism:
- Bind to β-tubulin, preventing microtubule polymerization.
- Block mitotic spindle formation → M-phase cell cycle arrest → apoptosis.
Comparison Table: Vinca Alkaloids
| Drug (Brand) | Major Indications | Dose-Limiting Toxicity | Other Toxicities | Key Pearls |
|---|---|---|---|---|
| Vincristine (Oncovin®) | ALL, NHL, HL, Wilms’ tumor, neuroblastoma, rhabdomyosarcoma, MM | Neurotoxicity (peripheral, autonomic, cranial) | SIADH, constipation/ileus, alopecia, vesicant, minimal myelosuppression | Max dose 2 mg; no renal adjustment, reduce in hepatic impairment; never give IT |
| Vinblastine (Velban®) | HL (ABVD), NHL, testicular cancer, Kaposi’s sarcoma | Myelosuppression (leukopenia) | Mild neurotoxicity, alopecia, GI upset, vesicant | Less neuropathy vs. vincristine; dose adjust hepatic impairment |
| Vinorelbine (Navelbine®) | NSCLC, breast cancer, ovarian cancer | Myelosuppression (neutropenia) | Neuropathy (mild-mod), constipation, SIADH, vesicant | Oral & IV forms; monitor ANC; hepatic dose adjustment |
| Vindesine (not widely used; investigational in some countries) | Leukemia, lymphoma, melanoma (rare use today) | Myelosuppression + neurotoxicity | Similar to vincristine & vinblastine | Mainly used in clinical trials; not routine in NA practice |
Class-wide Toxicities & Safety Issues
- Common: Alopecia, constipation, mucositis, vesicant (extravasation → necrosis).
- Fatal if given intrathecally (black box warning; universally lethal).
- Metabolism: Hepatic (CYP3A4); avoid strong inhibitors (azole antifungals, macrolides, protease inhibitors).
- Excretion: Mainly biliary → dose adjust in hepatic dysfunction (use bilirubin/AST for guidance).
- No renal adjustment required.
Pharmacist Pearls
- Dispense in IV minibags only (not syringes) to prevent intrathecal administration.
- Vincristine = pediatric regimens backbone (sparing marrow).
- Always check LFTs before dosing.
- For constipation prophylaxis (esp. vincristine), start bowel regimen early.
- Watch for SIADH with vincristine/vinblastine.
- Vinorelbine has oral formulation but limited by GI & myelosuppression.