Dosing and uses of Flutamide
Adult dosage forms and strengths
capsule
- 125mg
Prostate Cancer
250 mg PO q8hr
Take in combination with gonadotropin-releasing hormone (GnRH/LHRH) analogs
Pediatric dosage forms and strengths
Not indicated
Flutamide adverse (side) effects
>10%
Hot flashes (61%)
Decreased libido (36%)
Impotence (31%)
Diarrhea (12%)
Nausea/vomiting (11%)
1-10%
Gynecomastia (9%)
Anorexia (4%)
Edema (4%)
Leukopenia (3%)
Rash (3%)
Frequency not defined
Hemolytic anemia, methemoglobinemia
Increased AST, ALT, bilirubin, BUn
Warnings
Black box warnings
Hospitalization and rarely death have been reported due to hepatic failure associated with flutamide use. Hepatic failure may occur within 3 months of therapy initiation. The hepatic injury may be reversible in some patients following the discontinuation of therapy
Perform liver function tests if symptoms suggestive of liver dysfunction (eg, abdominal pain, fatigue, anorexia, flu-like symptoms, nausea, vomiting, jaundice, hyperbilirubinuria, right upper quadrant tenderness) occur
Discontinue therapy if patient develops jaundice or ALT rises above 2 times the upper limit of normaL
Contraindications
Hypersensitivity, severe hepatic disease
Cautions
Risk of severe liver injury
Potential for aniline toxicity (methemoglobinemia, hemolytic anemia etc); specially monitor patients sensitive to aniline toxicity
Risk for cardiovascular disease may increase with androgen deprivation
Pregnancy and lactation
Pregnancy category: d
Lactation: Excretion in milk unknown; not recommended
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Flutamide
Mechanism of action
Nonsteroidal antiandrogen, competitively binds androgen receptors and inhibits testosterone stimulation of cell growth in prostate cancer
Pharmacokinetics
Half-Life: 6 hr
Peak Plasma Time: 6 hr
Protein Bound: 94-96%
Metabolism: Liver
Metabolites: 4-nitro-3-fluoro-methylaniline, 2-amino- 5-nitro- 4-(trifluoromethyl) phenoL
Excretion: Primarily urine; <5% in feces
Dialyzable: No
