Ovarian Carcinoma: Paclitaxel is used as both first-line and later-line treatment for advanced ovarian carcinoma. For first-line treatment, it is given in combination with cisplatin.

Breast Carcinoma: Paclitaxel is indicated as adjuvant therapy for node-positive breast cancer following standard doxorubicin-based combination chemotherapy. It is also used in metastatic breast cancer when combination chemotherapy has failed or when the disease returns within 6 months after adjuvant chemotherapy. Previous treatment should generally have included an anthracycline unless it is not clinically appropriate. Paclitaxel is also used as first-line therapy for advanced or metastatic breast cancer. It may be given together with an anthracycline in patients who are suitable for anthracycline treatment, or with trastuzumab in patients whose tumors overexpress HER2 at a 2+ or 3+ level by immunohistochemistry. Gemcitabine in combination with Paclitaxel is indicated for patients with unresectable, locally recurrent, or metastatic breast cancer that has relapsed after adjuvant or neoadjuvant chemotherapy. Prior chemotherapy should usually have included an anthracycline unless clinically contraindicated. Paclitaxel is also used with trastuzumab for metastatic breast cancer in patients whose tumors overexpress HER2 and who have not previously received chemotherapy for metastatic disease.

Non-Small Cell Lung Carcinoma: Paclitaxel, when used together with cisplatin, is indicated as first-line treatment for non-small cell lung cancer in patients who are not suitable candidates for potentially curative surgery or radiation therapy.

Kaposi's Sarcoma: Paclitaxel is indicated as second-line treatment for AIDS-related Kaposi's Sarcoma.

Gastric Carcinoma: Paclitaxel is indicated for the treatment of gastric carcinoma.

Important Note: Use this medicine only according to the advice of a registered physician.

Paclitaxel is an anti-microtubule agent that enhances the formation of microtubules from tubulin dimers and prevents their breakdown. By stabilizing these structures, it interferes with the normal reorganization of the microtubule network required for essential interphase and mitotic cell functions. Paclitaxel also causes the formation of abnormal microtubule bundles throughout the cell cycle and multiple asters during mitosis. After intravenous administration, plasma concentrations of Paclitaxel decline in two phases. The first rapid phase reflects distribution into peripheral tissues and elimination, while the later phase is partly due to the slow release of the drug from the peripheral compartment.

All patients should be premedicated prior to Paclitaxel administration in order to prevent severe hypersensitivity reactions. Such premedication may consist of dexamethasone 20 mg PO administered approximately 12 and 6 hours before Paclitaxel, diphenhydramine (or its equivalent) 50 mg IV 30 to 60 minutes prior to Paclitaxel, and cimetidine (300 mg) or ranitidine (50 mg) IV 30 to 60 minutes before Paclitaxel.

First-line treatment of ovarian cancer: Although alternative medication regimens for paclitaxel are under investigation at present, a combination therapy of paclitaxel and cisplatin is recommended. Depending on the duration of infusion, two different dosages are recommended for paclitaxel treatment: 175 mg/m2 of paclitaxel is administered as an intravenous infusion over a period of three hours followed thereafter by 75 mg/m2 of cisplatin and the therapy is repeated at 3-week intervals, or 135 mg/m2 of paclitaxel is administered as an intravenous infusion over a period of 24 hours followed thereafter by 75 mg/m2 of cisplatin and the therapy is repeated at 3-week intervals.

Second-line treatment of ovarian cancer: The recommended dose of paclitaxel is 175 mg/m2 administered over 3 hours, with a 3-week interval between courses.

Adjuvant chemotherapy in breast carcinoma: The recommended dose of paclitaxel is 175 mg/m2 administered over a period of 3 hours every 3 weeks for four courses, following AC therapy.

First-line chemotherapy of breast carcinoma: When used in combination with doxorubicin (50 mg/m2), paclitaxel should be administered 24 hours after doxorubicin. The recommended dose of paclitaxel is 220 mg/m2 administered intravenously over a period of 3 hours, with a 3-week interval between courses. When used in combination with trastuzumab, the recommended dose of paclitaxel is 175 mg/m2 administered intravenously over a period of 3 hours, with a 3-week interval between courses. Paclitaxel infusion may be started the day following the first dose of trastuzumab or immediately after the subsequent doses of trastuzumab if the preceding dose of trastuzumab was well tolerated.

Second-line chemotherapy of breast carcinoma: The recommended dose of paclitaxel is 175 mg/m2 administered over a period of 3 hours, with a 3-week interval between courses.

Advanced non-small cell lung cancer: The recommended dose of paclitaxel is 175 mg/m2 administered over 3 hours followed by 80 mg/m2 of cisplatin, with a 3-week interval between courses.

Treatment of AIDS-related KS: The recommended dose of paclitaxel is 100 mg/m2 administered as a 3-hour intravenous infusion every two weeks.

Dose adjustment: Subsequent doses of paclitaxel should be administered according to individual patient tolerance. Paclitaxel should not be re-administered until the neutrophil count is >1.5 x 109/l (>1 x 109/l for KS patients) and the platelet count is >100 x 109/l (>75 x 109/l for KS patients).

Paclitaxel clearance is not altered by cimetidine premedication.

Cisplatin:
When paclitaxel is administered after cisplatin, it may cause greater bone marrow suppression and reduce paclitaxel clearance by about 20%. In gynecological cancers, using paclitaxel with cisplatin may also increase the risk of renal failure compared with cisplatin alone.

Doxorubicin:
If paclitaxel and doxorubicin are given too close together, the elimination of doxorubicin and its active metabolites may be reduced. For the initial treatment of metastatic breast cancer, paclitaxel should therefore be administered 24 hours after doxorubicin. More severe neutropenia and stomatitis have been observed when paclitaxel was given before doxorubicin or infused over a longer period than recommended.

Liver-metabolized medicines:
Paclitaxel is metabolized partly by the cytochrome P450 enzymes CYP2C8 and CYP3A4. Therefore, caution is required when paclitaxel is used together with medicines that inhibit these enzymes, such as ketoconazole, erythromycin, fluoxetine, gemfibrozil, clopidogrel, cimetidine, ritonavir, saquinavir, indinavir, and nelfinavir, because this may increase paclitaxel toxicity. Concomitant use with enzyme inducers such as rifampicin, carbamazepine, phenytoin, efavirenz, and nevirapine is not recommended, as it may reduce paclitaxel effectiveness.

• Paclitaxel is contraindicated in patients with severe hypersensitivity reactions to paclitaxel, macrogolglycerol ricinoleate (polyoxyl castor oil).
•  Paclitaxel is contraindicated during lactation.
•  Paclitaxel should not be used in patients with baseline neutrophils <1.5x10^9/L (<1x10^9/L for KS patients) or platelets <100x10^9/L (<75x10^9/L for KS patients).
• In KS, paclitaxel is also contraindicated in patients with concurrent, serious, uncontrolled infections.
• Patients with severe hepatic impairment must not be treated with paclitaxel.

Common: Low blood counts leading to increased risk for infection, anemia and/or bleeding, hair loss, joint and muscle pain, peripheral neuropathy, nausea, vomiting (usually mild), diarrhea, mouth sores, hypersensitivity reaction, fever, facial flushing, chills, shortness of breath, or hives after paclitaxel is given.

Rare: Swelling of the feet or ankles (edema), liver problems, low blood pressure, darkening of the skin where previous radiation treatment has been given.

Paclitaxel is classified as Pregnancy Category D. Although adequate studies in pregnant women are lacking, paclitaxel may cause fetal harm when used during pregnancy, as with other cytotoxic medicines. It is contraindicated during lactation.

Paclitaxel should be administered under the supervision of a physician experienced in the use of cancer chemotherapeutic agents. Because significant hypersensitivity reactions may occur, appropriate supportive equipment should be available. Given the possibility of extravasation, it is advisable to closely monitor the infusion site for possible infiltration during drug administration. Paclitaxel should be given before cisplatin when used in combination.

Significant hypersensitivity reactions, characterized by dyspnea and hypotension requiring treatment, angioedema, and generalized urticaria, have occurred in less than 1% of patients receiving paclitaxel after adequate premedication. Fatal hypersensitivity reactions have occurred in patients despite premedication. These reactions are probably histamine-mediated. In the case of severe hypersensitivity reactions, paclitaxel infusion should be discontinued immediately.

Bone marrow suppression, primarily neutropenia, is the dose-limiting toxicity. Neutrophil nadirs occurred at a median of 11 days. Frequent monitoring of blood counts should be instituted. Patients should not be retreated until the neutrophil count is ≥1.5 x 10⁹/L (≥1 x 10⁹/L for KS patients) and platelets recover to ≥100 x 10⁹/L (≥75 x 10⁹/L for KS patients).

Severe cardiac conduction abnormalities have been reported rarely with single-agent paclitaxel. If patients develop significant conduction abnormalities during paclitaxel administration, appropriate therapy should be given, and continuous cardiac monitoring should be performed during subsequent therapy with paclitaxel. Let me know if you would like a Bengali version of this text as well.

Patients who experience severe neutropenia: (neutrophil count <0.5 x 10⁹/L for a minimum of 7 days) or severe peripheral neuropathy, should receive a dose reduction of 20% for subsequent courses (25% for KS patients).

Patients with hepatic impairment: Insufficient data are available to recommend dosage adjustments in patients with mild to moderate hepatic impairment. Patients with severe hepatic impairment must not be treated with paclitaxel.

Pediatric use: Paclitaxel is not recommended for use in children under 18 years due to a lack of data on safety and efficacy.

There is no specific antidote for paclitaxel overdose. In the event of overdose, the patient should be closely observed, and treatment should focus on the expected toxicities, including bone marrow suppression, peripheral neurotoxicity, and mucositis. In pediatric cases, overdose may also be associated with acute ethanol toxicity.

Cytotoxic Chemotherapy, Immunological Chemotherapy

Store in a dry place below 30°C. Protect from light and keep out of the reach of children. Only freshly prepared solution should be used.