BEXAROTENE

BEXAROTENE (bex-a-ro'teen) Targretin Classifications: antineoplastic agent; retinoid; Therapeutic: antineoplastic; retinoid Prototype: Isotretinoin Pregnancy Category: X

Availability

75 mg capsules; 1% gel

Action

Selectively binds to retinoid X receptors (RXR). Activation of the RXR pathway leads to cell death by interfering with cellular differentiation and proliferation of cells.

Therapeutic Effect

Inhibits the growth of tumor cells of squamous (skin) cell origin inducing tumor regression.

Uses

Treatment of cutaneous manifestations of cutaneous T-cell lymphoma.

Contraindications

Hypersensitivity to bexarotene; pregnancy (X), lactation. Safety and efficacy in children are not established.

Cautious Use

Hypersensitivity to retinoid agents; coronary artery disease; diabetes mellitus; alcoholism, history of pancreatitis, hepatitis; elevated triglycerides, hepatic impairment.

Route & Dosage

T-Cell Lymphoma Adult: PO 300 mg/m2/d as a single dose with a meal, if no response after 8 wk, may increase to 400 mg/m2/d. Adjust dose downward in 100 mg/m2/d increments if toxicity occurs Topical Apply once q.o.d. times 1 week, increase frequency at weekly intervals to once per day, b.i.d., t.i.d., and q.i.d.

Administration

Oral

• Give drug with or immediately following a meal.
• Do not give oral drug with grapefruit or grapefruit juice.
• Do not initiate therapy in a woman of childbearing age until the possibility of pregnancy has been completely ruled out.

Topical

• Apply a generous coating only to skin lesions; avoid normal skin.
• Do not cover with clothing until gel dries.
• Do not apply more frequently than prescribed.
• Store capsules and gel at 20°–25° C (36°–77° F). Protect from light and avoid high temperatures and humidity after bottle or tube is opened.

Adverse Effects (≥1%)

Body as a Whole: Headache, asthenia, infection, chills, fever, flu-like syndrome, back pain, bacterial infection. CNS: Insomnia. CV: Peripheral edema. GI: Abdominal pain, nausea, diarrhea, vomiting, anorexia. Endocrine: Hyperthyroidism. Hematologic: Leukopenia, anemia, hypochromic anemia. Metabolic: Hyperlipidemia, hypercholesterolemia, increased LDH. Skin: Rash, dry skin, exfoliative dermatitis, alopecia, photosensitivity.

Interactions

No clinically significant interactions established.

Pharmacokinetics

Absorption: Best with a fat-containing meal. Peak: 2 h. Distribution: >99% protein bound. Metabolism: Metabolized by CYP3A4. Elimination: Primarily in bile. Half-Life: 7 h.

Nursing Implications

Assessment & Drug Effects

• Monitor (with oral dose) for S&S of: hypothyroidism, hypertriglyceridemia, hypercholesterolemia, and pancreatitis.
• Lab tests (with oral dose): Baseline blood lipids, then weekly for 2–4 wk, and every 8 wk thereafter; baseline liver function tests, then repeat at 1, 2, 4 wk, and every 8 wk thereafter; baseline WBC and thyroid function tests, then repeat periodically thereafter; periodic serum calcium; for females, pregnancy test q mo throughout therapy.
• Withhold oral drug and notify physician if triglycerides >400 mg/dL or AST, ALT, or bilirubin >3 times upper limit of normal.

Patient & Family Education

• Use effective methods of contraception (both men and women) while taking/using this drug and for at least 1 mo after the last dose of the drug.
• Do not take this drug if you are or could be pregnant.
• Do not take this drug (oral form) if you are also taking gemfibrozil.
• Report immediately any of the following: Swelling in the face, lips, or wheezing; persistent bloating, constipation, diarrhea, vomiting, or stomach pain; persistent headache, severe drowsiness or weakness.
• Limit vitamin A intake to ≤15,000 IU/d while taking this drug (oral form).
• Report changes in vision to the physician. An ophthalmologic evaluation may be needed.
• Limit exposure to sunlight or sun lamps and wear sunscreen.
• Do not use insect repellents that contain the chemical, DEET, while using bexarotene gel.
• Report significant skin irritation.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug