Danazol, sold as Danocrine and other brand names, is a medication used in the treatment of endometriosis, fibrocystic breast disease, hereditary angioedema and other conditions.

[2] The use of danazol is limited by masculinizing side effects such as acne, excessive hair growth, and voice deepening.

Women taking danazol should practice effective contraception to prevent pregnancy if sexually active.

[24] Androgenic side effects are of concern, as some women taking danazol may experience unwanted hair growth (hirsutism), acne, irreversible deepening of the voice,[4] or adverse blood lipid profiles.

[16] The drug can act as both an agonist and antagonist of the PR depending on the bioassay, indicating that it could be regarded as a selective progesterone receptor modulator (SPRM).

[5] By occupying SHBG and CBG, danazol increases the ratio of free to plasma protein-bound testosterone, estradiol, progesterone, and cortisol.

[4][5] The table to the right shows the difference in testosterone levels in premenopausal women treated with danazol.

[41] The combination of its antiestrogenic, androgenic, and progestogenic or antiprogestogenic actions cause atrophy of the endometrium, which alleviates the symptoms of endometriosis.

[4][5][16][38][42] In men, danazol has been found to inhibit gonadotropin secretion and markedly decrease testosterone levels, likely due to its actions as a steroidogenesis inhibitor and antigonadotropin.

[2] Danazol is lipophilic and can partition into cell membranes, which indicates that it is likely to distribute deeply into tissue compartments.

[9][10][11][12][47] Danazol is or has been marketed under many brand names throughout the world including Anargil, Azol, Benzol, Bonzol, Cyclolady, Cyclomen, Danal, Danalol, Danamet, Danamin, Danasin, Danatrol, Danazant, Danazol, Danocrine, Danodiol, Danogen, Danokrin, Danol, Danonice, Danoval, Danzol, Dogalact (veterinary), Dorink, Dzol, Ectopal, Elle, Gonablok, Gong Fu Yi Kang, Gynadom, Kodazol, Kupdina, Ladogal, Lozana, Mastodanatrol, Nazol, Norciden, Vabon, and Winobanin.

[9][11][47] Danazol has been studied in the treatment of breast cancer in women, but produced relatively low response rates of about 15 to 20%.

[48][49] Low-dose danazol has been investigated in the treatment of diabetic macular edema in a phase III clinical trial.

[50][51] A 2016 phase I/II prospective study orally administered 800 mg per day to 27 patients with telomere diseases.

The primary efficacy endpoint was a 20% reduction in the annual rate of telomere attrition measured.

12 of 27 patients achieved the primary efficacy end point, 11 of whom increased telomere length at 24 months.

Hematologic responses (secondary efficacy endpoint) occurred in 10 of 12 patients who could be evaluated at 24 months.

Elevated liver-enzyme levels and muscle cramps (known adverse effects) of grade 2 or less occurred in 41% and 33% of the patients, respectively.