pac·li·tax·el (p k l -tk s l)n. An anticancer drug derived from the bark of the Pacific yew tree and used to treat ovarian and breast cancer that has not responded to prior therapy. |
Paclitaxel
paclitaxel,
paclitaxel (pak´litak´s
l),drug class: antineoplastic;
action: obtained from Western Yew tree, unique action inhibits microtubule network reorganization essential for cell division;
use: metastatic ovarian cancer.
paclitaxel Warning - Hazardous drug!
Onxol, Paxene (UK), Taxol
Pharmacologic class: Antimicrotubule agent
Therapeutic class: Antineoplastic
Pregnancy risk category D
FDA Boxed Warning
• Give injection under supervision of physician experienced in use of cancer chemotherapy, in facility with adequate diagnostic and treatment resources.
• Anaphylaxis and severe hypersensitivity reactions may occur despite premedication. All patients should be pretreated with corticosteroids, diphenhydramine, and histamine2 antagonists. Don't give drug to patients who've had previous severe reactions.
• Don't administer drug to patients with solid tumors whose baseline neutrophil counts are below 1,500 cells/mm3 or to patients with AIDS-related Kaposi's sarcoma whose baseline neutrophil counts are below 1,000 cells/mm3. To monitor for bone marrow suppression, obtain frequent peripheral blood cell counts on all patients.
• Albumin form of drug may substantially affect drug's functional properties. Don't substitute for or use with other paclitaxel forms.
Action
Stabilizes cellular microtubules to prevent depolymerization. This action inhibits microtubule network (essential for vital interphase and mitotic cellular functions) and induces abnormal microtubule arrays or bundles throughout cell cycle and during mitosis.
Availability
Concentrate for injection: 30 mg/5-ml vial, 100 mg/16.7-ml vial, 300 mg/50-ml vial
⊘Indications and dosages
➣ Advanced ovarian cancer
Adults: As first-line therapy, 175 mg/m2 I.V. over 3 hours q 3 weeks, or 135 mg/m2 I.V. over 24 hours q 3 weeks, followed by cisplatin. After failure of first-line therapy, 135 mg/m2 I.V. or 175 mg/m2 I.V. over 3 hours q 3 weeks.
➣ Breast cancer after failure of combination chemotherapy
Adults: As adjuvant treatment for node-positive breast cancer, 175 mg/m2 I.V. over 3 hours q 3 weeks for four courses given sequentially with doxorubicin combination chemotherapy. After chemotherapy failure for metastatic disease or relapse within 6 months of adjuvant therapy, 175 mg/m2 I.V. over 3 hours q 3 weeks.
➣ Non-small-cell lung cancer
Adults: 135 mg/m2 I.V. over 24 hours q 3 weeks, followed by cisplatin
➣ AIDS-related Kaposi's sarcoma
Adults: 135 mg/m2 I.V. over 3 hours q 3 weeks, or 100 mg/m2 I.V. over 3 hours q 2 weeks
Dosage adjustment
• Advanced human immunodeficiency virus infection (when used for Kaposi's sarcoma)
Off-label uses
• Advanced head and neck cancer
• Small-cell lung cancer
• Upper GI tract adenocarcinoma
• Non-Hodgkin's lymphoma
• Pancreatic cancer
• Polycystic kidney disease
Contraindications
• Hypersensitivity to drug or castor oil
• Solid tumors when baseline neutrophil count is below 1,500 cells/mm3
• AIDS-related Kaposi's sarcoma when baseline neutrophil count is below 1,000 cells/mm3
Precautions
Use cautiously in:
• severe hepatic impairment, active infection, decreased bone marrow reserve, chronic debilitating illness
• patients with childbearing potential
• breastfeeding patients (not recommended)
• children (safety not established).
Administration
☞ Follow facility protocol for handling chemotherapeutic drugs and preparing solutions.
• Dilute in dextrose 5% in water, normal saline solution, or dextrose 5% in lactated Ringer's solution per manufacturer's guidelines.
• Inspect solution for particles. Administer through polyethylene-lined administration set attached to 0.22-micron in-line filter.
• To prevent severe hypersensitivity reaction, premedicate with dexamethasone 20 mg 12 and 6 hours before infusion, as prescribed. Also give diphenhydramine 50 mg I.V., plus either cimetidine 300 mg or ranitidine 50 mg I.V. 30 to 60 minutes before paclitaxel.
☞ Keep epinephrine available. If severe hypersensitivity reaction occurs, stop infusion immediately and give epinephrine, I.V. fluids, and additional antihistamine and corticosteroid doses, as indicated and prescribed.
| Route | Onset | Peak | Duration |
| I.V. | Unknown | Unknown | Unknown |
Adverse reactions
CNS: peripheral neuropathy
CV: hypotension, hypertension, syncope, abnormal ECG, bradycardia, venous thrombosis
GI: nausea, vomiting, diarrhea, stomatitis, mucositis
Hematologic: anemia, leukopenia, neutropenia, bleeding, thrombocytopenia
Musculoskeletal: joint pain, myalgia
Skin: alopecia, radiation reactions
Other: infection, injection site reaction, hypersensitivity reactions including anaphylaxis
Interactions
Drug-drug. Carbamazepine, phenobarbital: decreased paclitaxel blood level and efficacy
Cisplatin: increased bone marrow depression (when paclitaxel dose follows cisplatin dose)
Cyclosporine, diazepam, doxorubicin, felodipine, ketoconazole, midazolam: inhibited paclitaxel metabolism and greater risk of toxicity
Doxorubicin: increased doxorubicin blood level and toxicity
Live-virus vaccines: decreased antibody response to vaccine, increased risk of adverse reactions
Other antineoplastics: increased risk of bone marrow depression
Drug-diagnostic tests. Liver function tests: abnormal results
Triglycerides: increased levels
Patient monitoring
☞ Watch closely for hypersensitivity reaction.
• Monitor heart rate and blood pressure.
• Assess infusion site for local effects and extravasation, especially during prolonged infusion.
☞ Monitor CBC, including platelet count. If neutropenia develops, monitor patient for infection; if thrombocytopenia develops, watch for signs and symptoms of bleeding.
• If patient has preexisting cardiac conduction abnormality, maintain continuous cardiac monitoring.
Patient teaching
• Instruct neutropenic patient to minimize infection risk by avoiding crowds, plants, and fresh fruits and vegetables.
• Tell thrombocytopenic patient to avoid activities that can cause injury. Advise him to use soft toothbrush and electric razor.
☞ Advise patient to promptly report signs and symptoms of infection, bleeding, or peripheral neuropathy (such as numbness and tingling of feet and hands).
• Tell patient to promptly report pain or burning at injection site.
• Explain that temporary hair loss may occur.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.
paclitaxel
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