FLUTAMIDE

(flu'ta-mide)

Eulexin
Classifications: antineoplastic; antiandrogen;
Therapeutic: antineoplastic
Pregnancy Category: D

Availability

125 mg capsules

Action

Nonsteroidal, nonhormonal, antiandrogenic drug that inhibits androgen uptake or binding of androgen to target tissues (i.e., prostatic cancer cells).

Therapeutic Effect

Interferes with the binding of both testosterone and dihydrotestosterone to target tissue (i.e., prostate cancer cells).

Uses

In combination with luteinizing hormone-releasing hormone agonists (i.e., leuprolide) or castration for early stage and metastatic prostate cancer.

Contraindications

Hypersensitivity to flutamide; severe liver impairment if ALT is equal to twice the normal value; females; pregnancy (category D), lactation.

Cautious Use

Lactase deficiency.

Route & Dosage

Prostate Cancer
Adult: PO 250 mg (2 caps) q8h

Administration

Oral

Use with caution in patients with severe hepatic impairment.
Store at 2°–30° C (36°–86° F) in a tightly closed, light-resistant container.

Adverse Effects (≥1%)

CNS: Drowsiness, confusion, depression, anxiety, nervousness. GI: Diarrhea, nausea, vomiting, anorexia, hepatitis, cholestatic jaundice, encephalopathy, hepatic necrosis, acute hepatic failure, may increase ALT, AST, bilirubin. Urogenital: Hot flashes, loss of libido, impotence. Hematologic: Anemia, leukopenia, thrombocytopenia. Skin: Rash. Body as a Whole: Edema. Endocrine: Gynecomastia, galactorrhea.

Interactions

Drug: may increase INR in patients on warfarin.

Pharmacokinetics

Absorption: Readily absorbed from GI tract. Onset: Antiandrogenic activity 2.2 h; symptomatic relief 2–4 wk. Duration: 3 mo–2.5 y, with an average of 10.5 mo. Metabolism: Metabolized in liver to at least 10 different metabolites; the major metabolite, 2-hydroxyflutamide (SCH-16423), is an alpha-hydroxylated derivative that is biologically active. Elimination: 98% in urine. Half-Life: 5–6 h.

Nursing Implications

Assessment & Drug Effects

Monitor therapeutic response with acid and alkaline phosphatase tests, bone and liver scans, chest x-ray, and physical exam.
Monitor for symptomatic relief of bone pain.
Assess for development of gynecomastia and galactorrhea; if these become bothersome, dosage reduction may be warranted.
Lab tests: Monitor liver function and serum bilirubin periodically.
Monitor for and report development of a lupus-like syndrome.

Patient & Family Education

Be aware of potential adverse effects of therapy.
Notify physician immediately of the following: Pain in upper abdomen, yellowing of skin and eyes, dark urine, respiratory problems, rashes on face, difficulty urinating, sore throat, fever, chills.

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

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