Flutamide
Flutamide is a first-generation non-steroidal androgen-receptor antagonist once used for prostate cancer and hirsutism/acne. Its use has fallen sharply because of a well-documented risk of severe, sometimes fatal hepatotoxicity, and it has been largely replaced by bicalutamide and safer agents.
01 Overview
Flutamide (Eulexin) blocks the androgen receptor and was historically prescribed for advanced prostate cancer and androgen-dependent skin conditions in women. It is effective but carries a black-box warning for hepatic failure.
Because safer AR antagonists now exist, flutamide is rarely first-line. It requires frequent liver monitoring and is generally avoided where alternatives are available.
02 Mechanism
Competitively antagonises the androgen receptor via its active metabolite hydroxyflutamide, blocking testosterone and DHT activity. Does not lower serum androgens directly.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Hirsutism (off-label) | 62.5–250 mg/day | Oral | Lower doses used off-label; hepatotoxicity risk persists |
| Prostate cancer | 250–750 mg/day | Oral | 250 mg three times daily historically |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Androgen-receptor blockadeReduces androgen-driven prostate growth and virilising features. | Strong | Clinical | |
| Reduced hirsutism (off-label)Decreases unwanted hair growth in women, though safer options are preferred. | Effective | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Severe hepatotoxicityCan cause fulminant hepatic failure and death; carries a regulatory warning. | Life-threatening | Uncommon but serious | Clinical | |
| GynecomastiaBreast growth and tenderness in men from AR blockade. | Moderate | Common | Clinical |