Flutamide was originally discovered in 1967 by Schering-Plough as a potential antibiotic, but researchers later recognized its antiandrogen effects. Clinical trials began in 1971, and the drug was introduced in Germany in 1983 before receiving U.S. FDA approval in 1989 for prostate cancer treatment. As the first nonsteroidal antiandrogen available, it has also been used off-label for conditions such as hirsutism in women, though concerns about liver toxicity have limited its broader use. Flutamide is a nonsteroidal anti-androgen medication mainly used to treat prostate cancer by blocking the action of male hormones such as testosterone and dihydrotestosterone (DHT). It works by attaching to androgen receptors, preventing these hormones from stimulating cancer cell growth. Taken orally in capsule form—often together with an LHRH analog—it can also be prescribed for other conditions linked to excess androgens, including hirsutism and acne.
BRAND NAMES
Eulexin
Flutamin
Generic Flutamide (various manufacturers)
Sold under multiple regional brand names worldwide
Availability varies by country due to safety restrictions
MECHANISM OF ACTION
Flutamide works by blocking the activity of male hormones such as testosterone and dihydrotestosterone (DHT). It attaches to androgen receptors in target tissues, preventing these hormones from promoting cell growth. This blockade slows the development and progression of androgen-dependent prostate cancer. The drug acts as a competitive antagonist, meaning it competes with natural hormones for binding sites. As a result, cancer cells lose one of their primary growth stimuli.
PHARMACOKINETICS
Absorption
Flutamide is taken orally and is well-absorbed into the bloodstream, where it converts into active metabolites. Its absorption may vary slightly with gastrointestinal and metabolic differences.
Distribution
After absorption, Flutamide spreads throughout the body and concentrates in androgen-responsive tissues. Plasma protein binding and liver function influence its distribution.
Metabolism
Flutamide is extensively metabolized in the liver into a more potent active metabolite. Liver impairment can alter this process and increase the risk of toxicity.
Excretion
Most metabolites are eliminated through the kidneys, with some excreted in bile. Excretion depends on healthy liver and kidney function for proper drug clearance.
PHARMACODYNAMICS
Flutamide reduces androgen-stimulated cellular activity by blocking hormone receptors. Its effects are most noticeable in tissues that rely heavily on androgen signaling. Over time, this reduces cell proliferation and lowers prostate cancer progression. The drug’s influence on hormone feedback systems can lead to increased testosterone production initially. Ultimately, it creates a hormonal environment less favorable for cancer cell survival.
ADMINISTRATION
Flutamide is taken orally, usually as a capsule. It is often prescribed alongside an LHRH analog to enhance therapeutic effect. The combination helps suppress androgen production and receptor activation simultaneously. Patients are typically instructed to maintain consistent timing with doses. Medical supervision is essential due to potential liver-related risks.
DOSAGE AND STRENGTH
Flutamide is available in 125 mg and 250 mg oral capsule/tablet strengths. The standard adult dosage for prostate cancer is 250 mg taken three times a day, for a total daily dose of 750 mg.
Dosage and Administration
The typical dosage regimen is:
Dose per administration: 250 mg.
Frequency: Three times daily, at 8-hour intervals.
Total daily dose: 750 mg.
DRUG INTERACTIONS
Flutamide has several significant drug interactions, primarily involving blood thinners (anticoagulants), medications that affect liver enzymes, and other agents that are also toxic to the liver. These interactions can increase the risk of bleeding, alter drug effectiveness, or cause liver damage.
FOOD INTERACTIONS
There are no known direct interactions between flutamide and food that affect the medicine's bioavailability or efficacy. It can be taken with or without food.
CONTRAINDICATIONS
Flutamide is contraindicated in patients with severe hepatic impairment and those with a known hypersensitivity to the drug or any of its components. It is also not approved for use in women, especially during pregnancy or lactation.
SIDE EFFECTS
Hot flashes → Flushing
Gastrointestinal issues → GI-distress
Sexual dysfunction → Impotence
Breast changes → Gynecomastia
Tiredness/weakness → Fatigue
Mood changes → Anxiety
Urine discoloration → Discoloration
OVER DOSE
Overdose may intensify side effects such as severe nausea, vomiting, or stomach distress. Liver toxicity risk increases significantly with excessive intake. Patients may experience confusion, dizziness, or abnormal fatigue. Immediate medical evaluation is required if an overdose is suspected. Treatment focuses on supportive care and monitoring organ function.
TOXICITY
Flutamide is known for its potential to cause liver toxicity, which can range from mild enzyme elevation to severe liver failure. Toxicity is more likely at high doses or in individuals with preexisting liver disease. Symptoms may include jaundice, abdominal pain, or dark urine. Regular liver-function monitoring is essential during therapy. Early detection can prevent long-term damage or life-threatening complications.
