Home Drug Guide Paclitaxel

Drug Guide

Generic Name

Paclitaxel

Brand Names Taxol, Abraxane

Classification

Therapeutic: Antineoplastic agent

Pharmacological: Mitotic inhibitor (taxane)

FDA Approved Indications

Ovarian cancer
Breast cancer
Non-small cell lung cancer
Pancreatic cancer
Kaposi's sarcoma

Mechanism of Action

Paclitaxel stabilizes microtubules by binding to the β-tubulin subunit, preventing depolymerization, which inhibits mitosis and promotes apoptosis in cancer cells.

Dosage and Administration

Adult: Dose varies based on indication, body surface area, and regimen. Typically 135-175 mg/m² IV infusion over 3 hours every 3 weeks.

Pediatric: Use is not well established; consult specific protocols for pediatric use.

Geriatric: Adjust dosing based on tolerance and comorbidities; monitor for increased toxicity.

Renal Impairment: No specific dose adjustment recommended, but caution advised.

Hepatic Impairment: Reduce dose in severe hepatic impairment; closely monitor hepatic function.

Pharmacokinetics

Absorption: Administered intravenously; no oral absorption data.

Distribution: Widely distributed, highly bound to plasma proteins (~89%).

Metabolism: Primarily metabolized hepatically by CYP2C8 and CYP3A4.

Excretion: Metabolites excreted in feces and urine.

Half Life: Approximately 6 hours, but prolonged in hepatic impairment.

Contraindications

Hypersensitivity to paclitaxel or Cremophor EL (for Taxol formulation).

Precautions

Severe hypersensitivity reactions, cardiomyopathy, pre-existing neutropenia, liver dysfunction, peripheral neuropathy, myelosuppression, cardiovascular disease.

Adverse Reactions - Common

Neutropenia (Very common)
Peripheral neuropathy (Common)
Nausea and vomiting (Common)
Alopecia (Common)
Mucositis (Common)

Adverse Reactions - Serious

Anaphylactic reactions (Rare)
Myocardial ischemia or arrhythmias (Rare)
Severe neutropenia leading to infections (Serious)

Drug-Drug Interactions

Increased cardiotoxicity with anthracyclines.
Increased myelosuppression with other myelosuppressive agents.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor CBC, hepatic function, renal function, and neurological status.

Diagnoses:

Risk for infection due to neutropenia.
Risk for peripheral neuropathy.

Implementation: Administer slow IV infusion; premedicate with corticosteroids, antihistamines, and H2 antagonists to reduce hypersensitivity reactions.

Evaluation: Assess for adverse effects, treatment response, and toxicity.

Patient/Family Teaching

Report any signs of allergic reactions immediately.
Use reliable contraception during and for 6 months after treatment.
Report signs of infection, neuropathy, or unusual bleeding.

Special Considerations

Black Box Warnings:

Severe hypersensitivity reactions, including anaphylaxis.
Myelosuppression leading to neutropenia.
Peripheral neuropathy.

Genetic Factors: CYP2C8 polymorphisms may affect metabolism.

Lab Test Interference: May cause false elevation in transaminase levels.

Overdose Management

Signs/Symptoms: Severe neutropenia, allergic reactions, cardiovascular collapse.

Treatment: Supportive care; stop paclitaxel infusion; treat symptoms accordingly; consider use of corticosteroids or antihistamines for hypersensitivity.

Storage and Handling

Storage: Store vials at 2-8°C (36-46°F); protect from light.

Stability: Stable for specified period as per manufacturer's instructions.