Danazol

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Medically reviewed

Laura Arias

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Danazol

Property Description
Active ingredient Danazol
Form Oral Capsule
Pharmacological Class Gonadotropin Inhibitor / Synthetic Androgen
General Purpose To create a low-estrogen environment
Origin Synthetic Steroid (derived from 17alpha-ethinyltestosterone)

What Type of Medicine is Danazol?

Danazol is a synthetic steroid medication primarily classified as a gonadotropin inhibitor and a synthetic androgen. This compound is a single-ingredient, prescription-only hormonal agent derived from 17alpha-ethinyltestosterone (ethisterone). Its structure is engineered to interact directly with endocrine receptors.

As an International Nonproprietary Name (INN) product, Danazol is the active substance in several well-known brands. It falls into a specialized pharmacological class of antigonadotropic agents. This classification indicates that the medicine works by suppressing hormone signals, differentiating it from purely estrogen or progestin replacement therapies. It is consistently supplied as an oral capsule, which is taken by mouth for systemic absorption.


What is the General Purpose of This Hormonal Agent?

The general therapeutic purpose of Danazol is to manage specific chronic conditions that are clinically recognized to benefit from a significant reduction in cyclical hormonal activity. It achieves this by acting upstream in the body's hormone-signaling system.

The primary action involves the suppression of the pituitary-ovarian axis, meaning it slows the signals from the brain that stimulate the ovaries. By inhibiting the release of key gonadotropins—specifically Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH)—Danazol effectively reduces the ovaries' natural production of estrogen and progesterone. This fundamental hormonal suppression is central to the drug's activity and effects. This action creates a relatively low-estrogen environment, which is the general mechanism providing stabilization and managing discomfort in conditions driven or exacerbated by high or fluctuating natural hormone levels.

Regulatory References

  1. MedlinePlus Drug Information

What side effects are possible with Danazol?

Possible Side Effects and Safety Information

The safety profile of Danazol, as documented in official regulatory sources, is defined by the high incidence of side effects related to its androgenic and hormone-suppressive properties, alongside warnings regarding serious organ-system risks.

Adverse Reaction Scope

The most frequent adverse reactions are often linked to the medication's hormonal actions. These commonly include androgenic effects such as voice deepening (hoarseness, pitch instability), acne, mild hirsutism, weight gain, and fluid retention. Menstrual disturbances, including amenorrhea (absence of menstruation) or spotting, are also commonly documented. Other common effects involve changes in libido, emotional lability, headache, flushing, and gastrointestinal issues like nausea.

Serious Adverse Reactions and Safety Constraints

Official labeling defines several rare but serious adverse reactions, which include thromboembolic events (such as stroke, sagittal sinus thrombosis, and deep vein thrombosis). Serious hepatobiliary complications, including peliosis hepatis and benign hepatic adenoma, are documented, particularly in association with prolonged use.

Use of the medication is contraindicated in several populations. It is contraindicated during pregnancy due to the risk of androgenic effects on the female fetus and for nursing mothers. The medication must also not be used in individuals with pre-existing severe hepatic, renal, or cardiac impairment. Furthermore, official regulatory documents require the mandatory exclusion of breast cancer before initiating treatment for fibrocystic breast disease.

Overdose and Emergency Response

Overdose and When to Seek Help

The regulatory profile for Danazol overdose emphasizes the potential for severe systemic events and mandates immediate action. No specific pharmacological antidote for Danazol is documented in official labeling; therefore, management focuses on symptomatic and supportive treatment.


Documented Manifestations and Emergency Actions

Overdose Presentation and Risk Required Emergency Action
Severe systemic signs: Collapse, seizure, trouble breathing, or inability to be awakened (unconsciousness). Call emergency services (e.g., 911) immediately and contact a Poison Control center for guidance.
Serious complications: Symptoms of Benign Intracranial Hypertension (severe headache, visual disturbances, nausea/vomiting), thromboembolic events, or signs of hepatic toxicity. Seek emergency medical treatment at once. If neurological symptoms are present, immediate discontinuation of Danazol is required, and specialist referral is mandated for screening for papilledema.

Overdose Structure Summary

The overdose profile is defined by the risk of life-threatening vascular, neurological, and hepatic complications, which necessitate urgent medical help. Patients with pre-existing markedly impaired hepatic, renal, or cardiac function face an increased risk of severe toxicity in an overdose scenario, as stated in regulatory documents.

Therapeutic Uses of Danazol

Quick Facts

  • Endometriosis: Offers management of symptoms associated with this condition.
  • Hereditary Angioedema (HAE): Aids in the prevention of recurrent swelling episodes (attacks).
  • Fibrocystic Breast Disease: May assist in addressing nodularity, pain, and tenderness in symptomatic cases.

What Danazol Treats: Main Uses and Benefits

Danazol is a prescription medication utilized in therapeutic contexts to address several specific medical conditions.

It is an option for the management of endometriosis, a condition where tissue similar to the uterine lining is present outside the uterus. The medication helps to diminish the presence of this tissue and may contribute to the relief of associated symptoms such as pelvic pain.

Danazol is also indicated for the prevention of attacks of hereditary angioedema (HAE), which is a rare, inherited disorder that results in episodic swelling of the extremities, face, airway, or intestines. Continued use can help maintain a stable state and may lead to a reduced frequency of swelling episodes.

For some patients with symptomatic fibrocystic breast disease, Danazol may be considered. In these cases, treatment is intended to assist in reducing breast pain, tenderness, and nodularity when simple measures are deemed insufficient. It is important to confirm the absence of breast cancer prior to initiating this therapy. This medication is part of a broader therapeutic approach and its use should align with the direction of a qualified healthcare professional.

Eligibility and Restrictions for Use

Population Eligibility and Contraindications

Danazol's official eligibility profile defines who may use the medicine and who is strictly prohibited, based on established regulatory standards.

Absolute Non-Eligibility

Use of Danazol is contraindicated and strictly prohibited for patients with certain high-risk conditions, including active or a history of thromboembolic disease (blood clots), porphyria, and any known or suspected androgen-dependent tumor. It is also contraindicated for individuals with undiagnosed abnormal genital bleeding.

Organ Function and Reproductive Status

The medicine is prohibited for patients with markedly impaired function of the heart, liver, or kidneys. Furthermore, Danazol is contraindicated during known or suspected pregnancy due to the risk of fetal harm; women of childbearing potential must use non-hormonal contraception. It is also contraindicated for women who are breastfeeding.

Age-Based and Conditional Use

The safety and effectiveness of Danazol have not been established in pediatric patients. For patients with symptomatic fibrocystic breast disease, carcinoma of the breast must be ruled out prior to starting treatment. Patients with conditions such as epilepsy, hypertension, or diabetes mellitus require careful observation or use with caution during therapy.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Danazol's official regulatory profile documents specific pharmacokinetic and pharmacodynamic interactions with co-administered substances. The most stringent restriction involves co-administration with certain HMG-CoA reductase inhibitors (statins). Co-administration with Simvastatin is formally contraindicated due to the significantly increased systemic exposure and resulting risk of muscle toxicity, including rhabdomyolysis. A similar metabolic interaction requires that the dose of Lovastatin must not exceed 20 mg per day.

This medicine acts as an inhibitor of CYP3A4 metabolism, which can elevate the plasma concentrations of certain co-administered drugs. Regulatory labeling notes this effect for immunosuppressants such as Ciclosporin and Tacrolimus, potentially increasing the risk of toxicity. Danazol also potentiates the action of oral anticoagulants like Warfarin, increasing the risk of bleeding and necessitating close monitoring.

Pharmacodynamic interactions are documented where Danazol may oppose the therapeutic action of anti-diabetic agents and anti-hypertensive agents by promoting insulin resistance or fluid retention. It may also decrease the effectiveness of hormonal contraceptives. Furthermore, subjective intolerance, including nausea and shortness of breath, is reported with co-administration of Ethyl Alcohol. Official information indicates that the consequences of interactions may be more significant in patients with existing hepatic or renal dysfunction.

Mechanism of Action

Suppression of the Central Endocrine Axis

Danazol's primary mechanism involves the inhibition of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) secretion from the anterior pituitary gland. This central action modulates the signaling loop known as the Hypothalamic-Pituitary-Ovarian (HPO) Axis. This suppression leads to the functional arrest of follicular development and ovarian activity, resulting in the establishment of a systemic hypoestrogenic environment and anovulation.


Peripheral Enzyme and Receptor Modulation

Danazol acts peripherally by inhibiting the Aromatase enzyme ( CYP19A1), which converts androgens into estrogens in local tissues. It also interacts with steroid receptors, exhibiting weak binding to the Androgen Receptor (AR), clear binding affinity for the Progesterone Receptor (PR), and some affinity for the Glucocorticoid Receptor (GR). This peripheral activity contributes to the anti-estrogenic status and imparts weak androgenic properties directly to target cells.


Altering Free Hormone Bioavailability

A crucial component of Danazol's mechanism is the suppression of Sex Hormone-Binding Globulin ( SHBG) synthesis in the liver. By reducing SHBG levels, Danazol causes a marked increase in the fraction of free, biologically active testosterone circulating in the bloodstream. This physiological shift contributes to the drug's functional androgenic effects.

Dosage and Administration Information

Administration Guidelines for Danazol

Danazol is a synthetic steroid available as an oral capsule and is administered systemically only by the oral route. The use of the medicine is characterized by specific procedural instructions and dose ranges.


Administration Scope

Property Instruction
Route of administration Oral (by mouth only).
Dosing schedule The total daily dose is administered in divided doses (mathbf2 to mathbf4 times per day, typically mathbf2).
Timing in relation to meals Must be taken with a meal to significantly enhance the extent of drug absorption (bioavailability), which can increase three- to fourfold compared to the fasted state.
Age-group administration rules The drug’s safety and efficacy have not been established in pediatric patients. Use is generally not recommended for the geriatric population.
Special procedural conditions In female patients, therapy must be initiated during menstruation (preferably on the first day). The use of non-hormonal contraception is required throughout the course of use.

Labeled Dosing Regimens

Indication Initial Daily Dose Range (Adults) Duration / Titration Logic
Endometriosis mathbf200 mg to mathbf800 mg daily, divided. Course is typically mathbf6 months and should not exceed mathbf9 months.
Fibrocystic Breast Disease mathbf100 mg to mathbf400 mg daily, divided. Typically administered for mathbf3 to mathbf6 months.
Hereditary Angioedema (HAE) mathbf400 mg to mathbf600 mg daily, divided. After a favorable response, the dose is gradually decreased by mathbf50% or less at intervals of mathbf1 to mathbf3 months to determine the minimal effective maintenance dose.

Connection to the overall use protocol: The protocol for Danazol emphasizes adherence to the oral route and requires the capsule to be consistently administered with food to optimize drug availability. The defined course durations and the mandatory initiation during the menstrual cycle establish the standard, time-bound, and cyclical nature of its use.

Recent Clinical Evidence

Research evidence / Overview of studies for Danazol


Evidence for Use in Endometriosis

Clinical research exploring Danazol for endometriosis has typically been conducted using short-term Randomized Controlled Trials (RCTs) and systematic reviews. These studies were applied in research exploring how symptoms change over time in adult premenopausal women diagnosed with endometriosis. As documented in these clinical trials and reviews, researchers examined specific outcomes related to the measurement of pelvic pain and studies monitored documented changes in the size of the tissue implants.

Research highlights changes measured during the study period, with some trials reporting patterns observed in the studies related to changes in measured pain during the study period. Studies also report how symptoms evolved in the observed populations after the treatment was completed, with research consistently monitoring the pattern of symptom recurrence following the cessation of the study period.


Evidence for Use in Hereditary Angioedema (HAE)

For Hereditary Angioedema (HAE), a rare condition characterized by fluctuating or episodic manifestations of swelling, the evidence relies more heavily on long-term Observational Studies, Prospective Cohort Studies, and clinical experience gathered over many years. Observational and cohort studies reported that this research primarily involved adult males and females, including adolescents (typically 12 years and older), diagnosed with HAE.

Studies monitored outcomes describing episodic or acute changes, focusing on the measurement of the frequency and documented severity of swelling attacks. Findings indicate patterns observed during chronic use related to the frequency of acute episodes, and studies described concurrent measurements of increased levels of C1-INH and C4 in the observed populations.


What is Still Uncertain in the Research Record

The evidence landscape, while documenting specific patterns, also highlights areas where certainty remains low. The long-term effects of Danazol, particularly for managing endometriosis and fibrocystic breast disease, are not fully established, as follow-up durations were limited in many key studies. Comparative evidence is limited regarding outcomes versus newer treatments developed in recent decades.

Additionally, due to the nature of older trials and the rarity of HAE, sample sizes were small for some research areas. Finally, the evidence is inconsistent across studies, and findings were inconsistent for specific endpoints, such as the change in nodularity in breast disease, meaning subgroup findings are uncertain for those particular patient groups.

Key Studies & References

  1. HAE Treatment Guidelines - HAEA - US Hereditary Angioedema Association (Clinical Guideline/Chronic Management)
  2. Danazol Therapy in Hereditary Angioedema - Henry Ford Health Scholarly Commons (Long-term Observational Data)

Frequently Asked Questions (FAQ)

Common questions about Danazol (FAQ)


Q: Can Danazol affect my mood or cause depression?

A: Official information lists depression, nervousness, anxiety, and emotional lability (which means mood swings) among the reported potential side effects of Danazol. If mood changes are experienced, official guidance recommends consultation with a healthcare provider.


Q: Are there any common over-the-counter medicines that interact with Danazol?

A: Regulatory documents indicate that Danazol may influence the action of certain co-administered drugs. This may include altering the effectiveness of anti-diabetic agents and certain common analgesics (pain relievers). Regulatory guidance recommends that the co-administration of all prescription and non-prescription medicines be reviewed with a healthcare provider.


Q: Does Danazol interact with birth control pills?

A: Yes, regulatory documents state that Danazol may decrease the effectiveness of hormonal contraceptives, which includes birth control pills. Because of this, official prescribing information advises women of childbearing potential to use a non-hormonal method of contraception throughout the course of treatment.


Q: Is it safe to drink alcohol while taking Danazol?

A: Official documentation reports that co-administration with Ethyl Alcohol has been associated with subjective intolerance. This is described as symptoms such as nausea and shortness of breath that have been reported to occur when alcohol is consumed.


Q: How long can a person safely take Danazol?

A: The required duration of use depends on the condition being treated, as defined in regulatory labeling. For endometriosis, the course is typically 6 months and the typical treatment course does not exceed 9 months. For long-term conditions like hereditary angioedema (HAE), the dose is reduced to the minimal effective maintenance dose, but regulatory documents note that experience with very long-term therapy is limited.


Q: Are long-term side effects a concern with Danazol?

A: Official documents describe that certain serious adverse reactions are associated with prolonged use of Danazol. These include potential hepatobiliary complications (such as peliosis hepatis or hepatic adenoma). The existence of these serious risks is noted in relation to prolonged use, and this factor contributes to the defined course limits for some indications.


Q: Does Danazol affect cholesterol levels?

A: Official product information notes that alterations of lipid metabolism are among the observed adverse effects. This means that changes to lipid profiles, which include cholesterol and triglyceride levels, have been reported during treatment.


Q: Can taking Danazol cause acne?

A: Yes, official safety information lists acne as a common side effect reported during use. This is categorized as an androgenic-like effect resulting from the medicine's hormone-modulating properties.


Q: Is it common to have hot flashes while taking Danazol?

A: Yes, official regulatory documents report flushing as a common side effect. Flushing is the clinical term often used to describe the experience of hot flashes.


Q: Can people with kidney problems use Danazol?

A: The medicine is strictly contraindicated (prohibited) for individuals with markedly impaired renal (kidney) function. Patients with less severe kidney impairment are listed as a condition requiring careful observation during therapy.


Q: Can people with heart problems use Danazol?

A: The use of Danazol is contraindicated for individuals with markedly impaired cardiac (heart) function. For patients with pre-existing conditions, such as hypertension (high blood pressure), they are listed as a condition requiring careful observation during therapy.


Q: Are there different Danazol doses available?

A: While the dosage ranges prescribed for different conditions vary widely, the original FDA-approved capsule strengths included 50 mg, 100 mg, and 200 mg.


Q: What is the typical experience regarding returning periods after stopping Danazol?

A: Official product information states that following the cessation of therapy, cyclical bleeding and ovulation usually return within 60 to 90 days. However, it is reported that persistent amenorrhoea (absence of periods) has occasionally been observed.


Q: How quickly does Danazol start working for symptoms?

A: Official product information indicates that for the treatment of endometriosis, the rapid relief of painful symptoms is observed, particularly when higher doses are used. The specific time frame for the onset of relief is not universally defined in the regulatory documents.


Q: What should I expect the first few weeks after starting Danazol?

A: In the early phase of treatment, official documents state that patients commonly report menstrual disturbances, which can include spotting or absence of periods. Other potential androgenic effects, such as weight gain or acne, may also begin to appear.


Q: Can Danazol cause weight gain?

A: Yes, the product's safety information lists weight gain as a common side effect reported in association with its use. This is categorized as one of the medicine's androgenic-like effects.


Q: Are changes in my voice a common side effect of Danazol?

A: Voice change is listed in official documents as a common androgenic-like effect. This can manifest as hoarseness, pitch instability, or a deepening of the voice, and this change may occasionally persist even after treatment has ended.


Q: Is Danazol known to cause hair loss or extra hair growth?

A: Official documentation reports both types of hair changes as potential androgenic-like effects. Both mild hirsutism (extra hair growth) and hair loss have been reported in safety information.


Q: Do menstrual periods stop while taking Danazol?

A: The medication is designed to suppress ovarian function, and amenorrhoea (the absence of menstruation) is a commonly documented effect during therapy. However, some women may experience other menstrual disturbances, such as spotting.


Q: Can Danazol be used by men?

A: Yes, official indications for Danazol include the prevention of attacks of Hereditary Angioedema (HAE), a condition for which the drug is used in both adult males and females.


Q: Is Danazol a hormone replacement therapy?

A: No, Danazol is not classified as a hormone replacement therapy. Official sources define it as a synthetic steroid and an antigonadotropic agent. This means it works by suppressing the body’s natural hormone production, which is different from hormone replacement therapy.


Q: Does Danazol affect future fertility?

A: For women, cyclical bleeding and ovulation usually return within 60 to 90 days after stopping treatment, suggesting that the effect on fertility is generally temporary. For men, regulatory documents note that while some reductions in sperm production have been observed, these effects were found to be reversible in studies.


Q: Why is regular pregnancy testing sometimes mentioned for patients taking Danazol?

A: The drug is contraindicated during pregnancy because of the risk of causing fetal harm, specifically the virilisation of a female fetus. To address this risk, regulatory documents describe the necessity of excluding pregnancy before starting therapy and using non-hormonal contraception throughout the treatment course.


Q: Is it possible for Danazol to stop working over time?

A: For the treatment of endometriosis, official documentation notes that the recurrence of symptoms is common after the completion of the therapy period. The observation of symptom recurrence following cessation of therapy is a factor in the defined duration limits found in official guidelines.


Q: Can Danazol cause fluid retention or swelling?

A: Yes, official product information lists fluid retention (edema) as a potential adverse effect. This retention can sometimes manifest as swelling of the feet or lower legs.


Q: Can Danazol cause problems with blood sugar?

A: Official information indicates that Danazol can cause insulin resistance. Caution is advised because this effect may require increased insulin needs in diabetic patients or impact the effectiveness of anti-diabetic medications.


Q: Does Danazol impact sex drive?

A: Yes, the safety information lists changes in libido (sex drive) as a potential effect. Both a decreased and sometimes an increased sex drive have been reported in official documents.


Q: Is Danazol effective for pain related to endometriosis?

A: Clinical trials and studies reviewed in official sources reported patterns consistent with relief of painful symptoms associated with endometriosis when compared to inactive treatment (placebo).


Q: Can Danazol cause muscle cramps or stiffness?

A: The safety profile documents muscle cramps or spasms and general muscle pains among the reported musculoskeletal adverse effects that may occur during treatment.


Q: Are there any known interactions between Danazol and common supplements like vitamins?

A: Official documents caution that Danazol can increase the body's response to synthetic vitamin D analogs. Other common vitamins and supplements are not universally addressed as a collective group in the standard regulatory labeling.


Q: Are there any dietary restrictions mentioned in the official information for Danazol?

A: While there are no general dietary restrictions listed in regulatory guidelines, the medicine is specifically required to be taken with a meal. This administration condition is necessary to significantly increase the amount of the drug that is absorbed into the body.

How should Danazol be stored and disposed of?

Danazol Storage and Disposal Instructions

Danazol capsules must be stored in a closed, light-resistant container at Controlled Room Temperature, defined as 20 C to 25 C (68 F to 77 F). The medication must be protected from excessive heat, moisture, and direct light. It is mandatory to keep this medication out of the reach of children and pets and to keep it from freezing.


Disposal of Unused Medicine

Official labeling instructs users not to keep outdated or unused medicine. Patients should ask a healthcare professional or pharmacist how to properly dispose of any unused Danazol capsules. General regulatory guidance recommends discarding unused medicine by mixing it with an unappealing substance, securing it in a sealed plastic bag, and placing it in household trash.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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