(FLOO ta mide)
- SCH 13521
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Generic: 125 mg
- Antineoplastic Agent, Antiandrogen
Nonsteroidal antiandrogen that inhibits androgen uptake and/or inhibits binding of androgen in target tissues.
Oral: Rapid and complete
Extensively hepatic to ≥6 metabolites, primarily 2-hydroxyflutamide (active)
Primarily urine (as metabolites); feces (~4%)
Time to Peak
~2 hours (2-hydroxyflutamide)
~6 hours (2-hydroxyflutamide)
Parent drug: 94% to 96%; 2-hydroxyflutamide: 92% to 94%
Special Populations: Renal Function Impairment
The half-life is slightly prolonged
Special Populations: Elderly
The half-life is slightly prolonged, ~9.6 hours (active metabolite at steady state)
Use: Labeled Indications
Prostate cancer: Management of locally confined Stage B2 to C and Stage D2 metastatic prostate cancer (in combination with a luteinizing hormone-releasing hormone [LHRH] agonist). For Stage B2 to C prostate cancer, flutamide treatment (and goserelin) should start 8 weeks prior to initiating radiation therapy and continue during radiation therapy. To achieve treatment benefit in Stage D2 metastatic prostate cancer, initiate flutamide with the LHRH agonist and continue until disease progression.
Hypersensitivity to flutamide or any component of the formulation; severe hepatic impairment (evaluate baseline hepatic enzymes prior to treatment).
Prostate cancer, metastatic: Males: Oral: 250 mg 3 times daily (every 8 hours)
Refer to adult dosing.
Dosing: Renal Impairment
No dosage adjustment is necessary in patients with chronic renal insufficiency.
Dosing: Hepatic Impairment
Mild to moderate impairment: There are no dosage adjustments provided in the manufacturer’s labeling.
Severe impairment: Use is contraindicated.
May be administered with or without food. Administer orally in 3 divided doses (every 8 hours).
Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F). Dispense with a child-resistant closure in a tight, light-resistant container.
Abiraterone Acetate: May increase the serum concentration of CYP1A2 Substrates. Monitor therapy
Cannabis: May decrease the serum concentration of CYP1A2 Substrates. Monitor therapy
Choline C 11: Antiandrogens may diminish the therapeutic effect of Choline C 11. Monitor therapy
CloZAPine: CYP1A2 Inhibitors (Weak) may increase the serum concentration of CloZAPine. Monitor therapy
CYP1A2 Inducers (Strong): May increase the metabolism of CYP1A2 Substrates. Management: Consider an alternative for one of the interacting drugs. Some combinations may be specifically contraindicated. Consult appropriate manufacturer labeling. Consider therapy modification
CYP1A2 Inhibitors (Moderate): May decrease the metabolism of CYP1A2 Substrates. Monitor therapy
CYP1A2 Inhibitors (Strong): May decrease the metabolism of CYP1A2 Substrates. Consider therapy modification
Cyproterone: May decrease the serum concentration of CYP1A2 Substrates. Monitor therapy
Dapsone (Topical): May enhance the adverse/toxic effect of Methemoglobinemia Associated Agents. Monitor therapy
Deferasirox: May increase the serum concentration of CYP1A2 Substrates. Monitor therapy
Indium 111 Capromab Pendetide: Antiandrogens may diminish the diagnostic effect of Indium 111 Capromab Pendetide. Avoid combination
Nitric Oxide: May enhance the adverse/toxic effect of Methemoglobinemia Associated Agents. Combinations of these agents may increase the likelihood of significant methemoglobinemia. Management: Monitor patients for signs of methemoglobinemia (e.g., hypoxia, cyanosis) when nitric oxide is used in combination with other agents associated with development of methemoglobinemia. Avoid lidocaine/prilocaine. Monitor therapy
Obeticholic Acid: May increase the serum concentration of CYP1A2 Substrates. Monitor therapy
Peginterferon Alfa-2b: May increase the serum concentration of CYP1A2 Substrates. Monitor therapy
Prilocaine: Methemoglobinemia Associated Agents may enhance the adverse/toxic effect of Prilocaine. Combinations of these agents may increase the likelihood of significant methemoglobinemia. Management: Monitor patients for signs of methemoglobinemia (e.g., hypoxia, cyanosis) when prilocaine is used in combination with other agents associated with development of methemoglobinemia. Avoid lidocaine/prilocaine in infants receiving such agents. Monitor therapy
Sodium Nitrite: Methemoglobinemia Associated Agents may enhance the adverse/toxic effect of Sodium Nitrite. Combinations of these agents may increase the likelihood of significant methemoglobinemia. Monitor therapy
Teriflunomide: May decrease the serum concentration of CYP1A2 Substrates. Monitor therapy
Tetracaine (Topical): May enhance the adverse/toxic effect of Methemoglobinemia Associated Agents. Monitor therapy
TiZANidine: CYP1A2 Inhibitors (Weak) may increase the serum concentration of TiZANidine. Management: Avoid these combinations when possible. If combined use cannot be avoided, initiate tizanidine at an adult dose of 2 mg and increase in 2-4 mg increments based on patient response. Monitor for increased effects of tizanidine, including adverse reactions. Consider therapy modification
Vemurafenib: May increase the serum concentration of CYP1A2 Substrates. Management: Consider alternatives to such combinations whenever possible, particularly if the CYP1A2 substrate has a relatively narrow therapeutic index. Consider therapy modification
Endocrine & metabolic: Hot flash (46% to 61%), galactorrhea (9% to 42%), decreased libido (36%), increased lactate dehydrogenase (transient; mild)
Gastrointestinal: Diarrhea (12% to 40%), vomiting (11% to 12%)
Genitourinary: Impotence (33%), cystitis (16%), breast tenderness
Hematologic & oncologic: Rectal hemorrhage (14%), tumor flare
Hepatic: Increased serum AST (transient; mild)
1% to 10%:
Cardiovascular: Edema (4%), hypertension (1%)
Central nervous system: Anxiety, confusion, depression, dizziness, drowsiness, headache, insomnia, nervousness
Dermatologic: Skin rash (3% to 8%), ecchymoses, pruritus
Endocrine & metabolic: Gynecomastia (9%)
Gastrointestinal: Nausea (9%), proctitis (8%), gastric distress (4% to 6%), anorexia (4%), constipation, dyspepsia, increased appetite
Genitourinary: Hematuria (7%)
Hematologic & oncologic: Anemia (6%), leukopenia (3%), thrombocytopenia (1%)
Infection: Herpes zoster
Neuromuscular & skeletal: Weakness (1%)
<1% (Limited to important or life-threatening): Cholestatic jaundice, hemolytic anemia, hepatic encephalopathy, hepatic failure, hepatic necrosis, hepatitis, hypersensitivity pneumonitis, increased blood urea nitrogen, increased gamma-glutamyl transferase, increased serum ALT, increased serum bilirubin, increased serum creatinine, jaundice, macrocytic anemia, malignant neoplasm of breast (male), methemoglobinemia, myocardial infarction, oligospermia, pulmonary embolism, skin photosensitivity, sulfhemoglobinemia, thrombophlebitis, urine discoloration (amber, yellow-green)
Concerns related to adverse effects:
• Gynecomastia: Gynecomastia may occur in patients receiving flutamide in combination with medical castration.
• Hepatic failure: [U.S. Boxed Warning]: Hospitalization and death (rare) due to liver failure have been reported in patients taking flutamide. Elevated serum transaminase levels, jaundice, hepatic encephalopathy, and acute hepatic failure have been reported. Hepatotoxicity was reversible after discontinuation in some cases. In about 50% of the cases, the onset of hepatotoxicity was within the first 3 months of treatment. Monitor serum transaminase levels at baseline, monthly for 4 months, and periodically thereafter. Also obtain liver function tests at the first symptoms suggestive of liver dysfunction (nausea, vomiting, abdominal pain, fatigue, anorexia, “flu-like” symptoms, hyperbilirubinuria, jaundice, or right upper quadrant tenderness). Use is not recommended in patients with ALT values greater than 2 times ULN; discontinue use immediately in patients with jaundice or if ALT rises above 2 times ULN. Use is contraindicated in patients with severe hepatic impairment.
• Cardiovascular disease: Androgen-deprivation therapy may increase the risk for cardiovascular disease (Levine, 2010).
• Hemoglobin M disease: Patients with hemoglobin M disease are at risk of toxicities associated with aniline exposure, including methemoglobinemia, hemolytic anemia, and cholestatic jaundice; monitor methemoglobin levels.
Concurrent drug therapy issues:
• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.
• Glucose-6 phosphate dehydrogenase deficiency: Patients with glucose-6 phosphate dehydrogenase deficiency are at risk of toxicities associated with aniline exposure, including methemoglobinemia, hemolytic anemia, and cholestatic jaundice; monitor methemoglobin levels.
• Smokers: Patients who smoke are at risk of toxicities associated with aniline exposure, including methemoglobinemia, hemolytic anemia, and cholestatic jaundice; monitor methemoglobin levels.
• Women: Not indicated for use in women and should not be used in women, particularly for nonserious or nonlife-threatening conditions.
Serum transaminases (at baseline, monthly for 4 months, and periodically thereafter); monitor liver function tests at the first sign or symptom of liver dysfunction (eg, nausea, vomiting, abdominal pain, fatigue, anorexia, flu-like symptoms, hyperbilirubinuria, jaundice, or right upper quadrant tenderness); monitor prostate specific antigen (PSA)
Pregnancy Risk Factor
Adverse events have been observed in animal reproduction studies. May cause fetal harm if administered in pregnancy. Flutamide is not indicated for use in women.
• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
• Patient may experience hot flashes, nausea, vomiting, enlarged breasts, decreased libido, or sexual dysfunction. Have patient report immediately to prescriber signs of infection, signs of liver problems (dark urine, feeling tired, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or yellow skin or eyes), signs of depression (suicidal ideation, anxiety, emotional instability, illogical thinking), blood in urine, rectal pain, rectal bleeding, severe headache, loss of strength and energy, bruising, bleeding, swelling of arms or legs, or severe diarrhea (HCAHPS).
• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.
Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.
More about flutamide
- Other brands: Eulexin