Flutamide (Eulexin) — Clinical FAQs

Question 1

What is Flutamide FDA-approved to treat?

Accepted Answer

Flutamide is FDA-approved for the following oncology indications: 1. Metastatic prostate carcinoma (Stage D2) in combination with a GnRH agonist (e.g., leuprolide) for maximal/combined androgen blockade 2. Locally confined Stage B2-C prostate carcinoma in combination with a GnRH agonist.

Question 2

How does Flutamide work (mechanism of action)?

Accepted Answer

Flutamide is a nonsteroidal, pure antiandrogen that, together with its active metabolite 2-hydroxyflutamide, competitively binds the androgen receptor and blocks the uptake and/or nuclear binding of androgens (testosterone and dihydrotestosterone) in target tissues. By preventing androgen-receptor interaction, it inhibits androgen-dependent transcription and growth of prostatic carcinoma cells. Because it lacks the negative feedback suppression of a steroidal antiandrogen, flutamide monotherapy raises LH and testosterone; it is therefore combined with medical or surgical castration (a GnRH agonist or orchiectomy) to achieve combined/maximal androgen blockade, and it counteracts the tumor flare that can accompany initiation of a GnRH agonist.

Question 3

How is Flutamide administered?

Accepted Answer

Flutamide is administered Oral (PO). Usual dose is 250 mg PO every 8 hours (750 mg/day) with or without food.

Question 4

What are the most common side effects of Flutamide?

Accepted Answer

The most commonly reported side effects of Flutamide (≥10% incidence) include: Hot flashes, Loss of libido and impotence, Gynecomastia and breast tenderness, Diarrhea and other GI disturbances, Nausea and vomiting and others (6 total). Consult your oncologist for complete prescribing information.

Question 5

Does Flutamide have a black box warning?

Accepted Answer

Yes. Flutamide carries FDA black box warning(s) regarding: 1. Hepatotoxicity: Serious and fatal hepatic injury (including hepatic encephalopathy, hepatic necrosis, and death) has been reported. Measure serum transaminases before starting, monthly for the first 4 months, and periodically thereafter; measure at the first sign or symptom of liver dysfunction. Discontinue immediately if ALT rises above 2 times the upper limit of normal or if jaundice/hepatic injury develops.

Question 6

Is Flutamide safe during pregnancy?

Accepted Answer

Flutamide pregnancy safety: Not indicated for use in women. Based on its antiandrogenic mechanism, flutamide can cause fetal harm (feminization of a male fetus) and should not be used during pregnancy.. Oncologists should review the complete prescribing information and discuss reproductive risks with patients before initiating therapy.

Flutamide — Drug Monograph

Mechanism of Action

FDA Indications

Common Side Effects

Clinical Pearl

Related Therapies & Mechanisms