trastuzumab

trastuzumab /tras·tuz·u·mab/ (tras-tuz´u-mab) a monoclonal antibody that binds to a protein overexpressed in some breast cancers; used as an antineoplastic in the treatment of metastatic breast cancer with such overexpression.

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tras·tu·zu·mab (trs-tz-mb)

n.

A monoclonal IgG antibody derived from recombinant DNA, used intravenously to treat metastatic breast cancer.

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trastuzumab,

a miscellaneous antineoplastic.

indications It is used in the treatment of metastatic breast cancer with the overexpression of HER2.

contraindications Factors that prohibit its use include known hypersensitivity to this drug or to Chinese hamster ovary cell protein.

adverse effects Life-threatening effects are tachycardia, congestive heart failure, and leukopenia. Other adverse reactions include depression, insomnia, neuropathy, peripheral neuritis, acne, herpes simplex, nausea, vomiting, anorexia, diarrhea, anemia, arthralgia, bone pain, edema, peripheral edema, cough, dyspnea, pharyngitis, rhinitis, and sinusitis. Common side effects include dizziness, numbness, paresthesias, rash, and flulike syndrome (fever, headache, chills).

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trastuzumab [tras-tuz´u-mab]

a monoclonal antibody that binds to a protein overexpressed in some breast cancers; used as an antineoplastic agent in treatment of metastatic breast cancer with such overexpression.

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trastuzumab Warning - High-alert drug!

Herceptin

Pharmacologic class: Recombinant DNA-derived monoclonal antibody

Therapeutic class: Antineoplastic

Pregnancy risk category B

FDA Boxed Warning

• Drug may cause ventricular dysfunction and heart failure. Evaluate left ventricular function in all patients before and during therapy. Strongly consider withdrawing drug if patient develops clinically significant decrease in left ventricular function. Incidence and severity of cardiac dysfunction were particularly high in patients who received drug in combination with anthracyclines and cyclophosphamide.

Action

Selectively binds to human epidermal growth factor receptor 2 (HER2), inhibiting proliferation of human tumor cells that overexpress HER2

Availability

Lyophilized powder: 440-mg vial (each vial contains 20 ml bacteriostatic water for injection, 1.1% benzyl alcohol)

⊘Indications and dosages

➣ Metastatic breast cancer in patients whose tumors overexpress HER2

Adults: As monotherapy, loading dose of 4 mg/kg I.V. infusion over 90 minutes, followed by weekly maintenance dose of 2 mg/kg I.V. infusion given over 30 minutes if loading dose was tolerated. Don't give by I.V. push.

Contraindications

• Hypersensitivity to drug

Precautions

Use cautiously in
• hypersensitivity to Chinese hamster ovary cell protein or to benzyl alcohol
• cardiac disease, anemia, leukopenia
• elderly patients
• pregnant or breastfeeding patients
• children younger than age 18 (safety and efficacy not established).

Administration

• Follow facility policy for handling, administering, and disposal of carcinogenic, mutagenic, and teratogenic agents.
• Give antiemetic, as prescribed, before administering trastuzumab.
☞ Administer by I.V. infusion only. Don't give by I.V. push or bolus.
• To reconstitute, add 20 ml of bacteriostatic water for injection to vial, pointing diluent stream at lyophilized cake. Swirl vial gently; don't shake. Withdraw prescribed dose and add it to 250 ml of normal saline solution. (Don't use dextrose 5% in water.)
• Infuse loading dose I.V. over 90 minutes. Infuse weekly doses I.V. over 30 minutes.
• Immediately after reconstituting, write a date that is 28 days from reconstitution date in the space after "Do not use after" on vial label.
• If patient has benzyl alcohol hypersensitivity, reconstitute with sterile water for injection. Use immediately after reconstitution; discard unused portion.
☞ Never administer intrathecally; doing so causes death.
• Know that for patient who hasn't previously received chemotherapy for metastatic disease, drug is given at same dosage but in combination with paclitaxel.

Route	Onset	Peak	Duration
I.V.	Unknown	Unknown	Unknown

Adverse reactions

CNS: dizziness, headache, depression, paresthesia, insomnia, ataxia, confusion, manic reaction, seizures

CV: peripheral edema, hypotension, tachycardia, syncope, arrhythmias, shock, pericardial effusion, vascular thrombosis, heart failure, cardiotoxicity, cardiac arrest

EENT: amblyopia, hearing loss

GI: nausea, vomiting, diarrhea, gastroenteritis, hematemesis, colitis, esophageal ulcer, stomatitis, ileus, anorexia, intestinal obstruction , pancreatitis

GU: urinary tract infection, hematuria, hemorrhagic cystitis, hydronephrosis, pyelonephritis, renal failure

Hematologic: coagulation disorder, pancytopenia, leukemia

Hepatic: ascites, hepatitis, hepatic failure

Metabolic: hypothyroidism, hypercalcemia, hyponatremia

Musculoskeletal: back, bone, or joint pain; myopathy; fractures; bone necrosis

Respiratory: upper respiratory infection, dyspnea, acute respiratory distress syndrome

Skin: cellulitis, rash, acne, herpes simplex, herpes zoster, skin ulcers

Other: weight loss, edema, infection, fever, chills, flulike syndrome, lymphangitis, hypersensitivity reactions including anaphylaxis, infusion reaction

Interactions

Drug-drug. Anthracyclines, cyclophosphamide: cardiotoxicity

Patient monitoring

☞ Monitor closely for signs and symptoms of infusion reaction (including respiratory distress). Halt infusion if these occur.
• Monitor vital signs, especially for hypotension and bradycardia.
☞ Use with extreme caution in patients with cardiac dysfunction. Assess cardiovascular status carefully; stay alert for heart failure and peripheral edema.
• Assess neurologic status for depression and paresthesia.
• Monitor respiratory status. Report increased dyspnea or flulike symptoms.
• Watch closely for signs and symptoms of infection, including herpes simplex.
• Monitor electrolyte levels and CBC with white cell differential.

Patient teaching

☞ Instruct patient to immediately report difficulty breathing, flulike symptoms, and fever, chills, and other signs and symptoms of infection.
☞ Advise patient to monitor weight. Tell him to report sudden weight gain as well as swelling and other signs and symptoms of heart failure.
☞ Instruct patient to immediately report abdominal pain, change in bowel habits, yellowing of skin or eyes, and easy bruising or bleeding.
• Tell patient drug may cause depression. Advise him (or significant other as appropriate) to contact prescriber if this occurs.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs mentioned above.

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trastuzumab

Herceptin^® Oncology A bioengineered monoclonal antibody used to manage Pts with breast CA who overexpress HER2, which transmits growth signals to breast CA cells. See HER2.