Paclitaxel is a mitotic inhibitor and antineoplastic agent derived from the bark of the Pacific yew tree (Taxus brevifolia). It is a microtubule-stabilizing agent that promotes the assembly of microtubules from tubulin dimers and stabilizes microtubules by preventing depolymerization. This stability inhibits the normal dynamic reorganization of the microtubule network essential for vital interphase and mitotic cellular functions. In the Indian market, it is a cornerstone of chemotherapy regimens for various solid tumors, available in both conventional and albumin-bound formulations.
Adult: Dose varies by indication. Common regimens: Ovarian Cancer: 135-175 mg/m² IV over 3 hours or 24 hours every 3 weeks. Breast Cancer: 175 mg/m² IV over 3 hours every 3 weeks. NSCLC: 135 mg/m² IV over 24 hours followed by cisplatin, every 3 weeks. The 30mg vial is used as part of the total calculated dose.
Note: MUST BE DILUTED. Reconstitute the 30mg vial with appropriate volume of diluent (e.g., 0.9% Sodium Chloride, 5% Dextrose) as per manufacturer's instructions. The final concentration should be between 0.3 to 1.2 mg/mL. Administer via IV infusion using a non-PVC (polyolefin) container and administration set with an in-line filter (0.22 micron or less) to minimize leaching of DEHP from PVC. Premedicate with dexamethasone, diphenhydramine, and an H2 antagonist approximately 30-60 minutes prior to infusion. Infuse over 3 or 24 hours as per protocol. Monitor closely for hypersensitivity reactions, especially during the first 30 minutes.
Paclitaxel binds specifically to the β-tubulin subunit of microtubules, enhancing microtubule polymerization and assembly. It stabilizes the microtubule polymer, protecting it from disassembly. This stabilization interferes with the normal dynamic reorganization of the microtubule network that is essential for vital interphase and mitotic cellular functions, leading to the inhibition of cell division.
Pregnancy: Pregnancy Category D (US FDA). There is positive evidence of human fetal risk. Paclitaxel is teratogenic and embryotoxic in animal studies. Can cause fetal harm. Contraindicated in pregnancy. Women of childbearing potential must use effective contraception during and for at least 6 months after therapy.
Driving: May cause fatigue, dizziness, or peripheral neuropathy, impairing the ability to drive or operate machinery. Patients should be cautioned.
| Cisplatin | Sequence matters. Administering cisplatin BEFORE paclitaxel increases the severity of myelosuppression. Paclitaxel should be given BEFORE cisplatin to minimize this interaction. | Major |
| Doxorubicin | Paclitaxel reduces the clearance of doxorubicin, increasing the risk of cardiotoxicity and neutropenia. Monitor cardiac function closely. | Major |
| Ketoconazole, Itraconazole, Clarithromycin | Strong CYP3A4 inhibitors; may increase paclitaxel plasma concentrations and toxicity. | Moderate |
| Rifampicin, Phenytoin, Carbamazepine | CYP3A4/CYP2C8 inducers; may decrease paclitaxel plasma concentrations and efficacy. | Moderate |
| Live Vaccines (e.g., MMR, Varicella) | Risk of severe or fatal infection due to immunosuppression. Avoid. | Major |
Same composition (Paclitaxel (30mg)), different brands: