Danocrine (Danazol)

Danocrine (danazol) is a synthetic steroid derived from ethisterone that has a structure similar to testosterone, an androgen or male sex hormone. Discovered in 1963, it has been in medical use since 1971.

Danocrine, taken in oral capsule form, is approved by the U.S. Food and Drug Administration (FDA) to treat symptoms due to endometriosis, benign breast nodules, and hereditary angioedema.

How Danocrine works

Danocrine mainly works by suppressing hormone production by the pituitary and sex glands (gonads), which are responsible for sexual development and reproduction. Danocrine has multiple effects on the body, including many androgenic — or male-like — side effects.

In hereditary angioedema, a rare genetic disorder marked by insufficient blood levels of the C1 esterase inhibitor (C1INH) protein and C4 protein, Danocrine helps to prevent spontaneous edema attacks by increasing C1INH and C4 levels in the blood. Exactly how it regulates these protein levels is not fully understood.

Danocrine in clinical trials

A number of clinical and retrospective studies, dating back to the mid-1970s, assessed Danocrine in managing symptoms of hereditary angioedema.

Results of a double-blinded clinical trial in nine patients, reported in The New England Journal of Medicine in 1976, evaluated Danocrine’s efficacy in preventing acute hereditary angioedema attacks. Among patients randomized to receive a 46-treatment course of Danocrine, only one had an angioedema attack while under treatment. Among patients given 47 courses of a placebo, a total of 44 attacks were recorded. Data also showed that C1INH and C4 protein levels increased in treated patients immediately upon using Danocrine, and reached maximal levels in one or two weeks of treatment, suggesting the medication could “correct the underlying biochemical abnormality.”

Another study, whose results were published The Journal of Allergy and Clinical Immunology in 1980, assessed 12 patients treated first daily with Danocrine and then intermittently (five days on treatment; five days off treatment) over a long term, or up to 25 months.  Eleven of the 12 patient experienced a complete remission, with no attacks. C1INH and C4 protein levels in patients’ blood were also seen to increase with treatment. Side effects were reported to be minimal.

A long-term survey of Danocrine use, published in 2008, reported on 118 hereditary angioedema patients in Germany and Denmark using the treatment from two months to up to 30 years. Almost all patients (111 of 118) responded to the treatment, and a near majority (54  or 45.8%) reported experiencing one or fewer attacks each year. Others reported their attacks were milder with the treatment. Side effects ranging from weight gain and virilization (or male-like characteristics in women), to menstrual irregularities and headache or depression were reported by in 93 of the 118 patients, and led 30 to stop the treatment.

Because Danocrine influences the hormone balance in the body, the therapy can cause developmental problems in children and adolescents. But a recent study that followed 42 hereditary angioedema patients — one group ages 15 or younger, the other ages 20 or younger — treated with Danocrine found no delay in normal development during puberty. Findings, the researchers wrote, “suggest that treatment with the lowest effective doses of danazol does not influence growth.”

Additional information

Due to its interference with sex hormones, the most common side effects of Danocrine are acne, weight gain, deepening of the voice, male-like hair growth, and menstrual irregularities.

There is a risk of long-term Danocrine treatment causing liver damage. Liver problems can be recognized by dark urine, stomach pain, yellowing of the skin or the eyes, fatigue, or bruising.


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