Danazol

Danazol is a synthetic steroid derivative with potent androgenic and anti-gonadotropic properties, primarily indicated for the treatment of endometriosis and hereditary angioedema. It functions by suppressing pituitary-ovarian axis activity, leading to reduced estrogen production and creating a high-androgen, low-estrogen environment that inhibits endometrial tissue growth. Its immunomodulatory effects make it valuable in managing attacks of hereditary angioedema by increasing levels of functional C1 esterase inhibitor. With decades of clinical use, danazol remains a cornerstone therapy for these specific conditions when first-line treatments are ineffective or contraindicated.

Features

• Synthetic steroid derived from ethisterone with attenuated androgenic activity
• Available in 50 mg, 100 mg, and 200 mg capsules for oral administration
• Half-life of approximately 15 hours with hepatic metabolism
• High protein binding capacity (>95%)
• Multiple generic formulations available alongside brand versions
• Requires prescription and medical supervision throughout treatment

Benefits

• Provides significant pain relief for endometriosis patients within 2-3 months of initiation
• Reduces frequency and severity of hereditary angioedema attacks by 70-90%
• Creates amenorrhea, allowing endometrial lesions to atrophy
• Offers alternative therapy when hormonal contraceptives are contraindicated
• Prevents surgical intervention in many cases of moderate endometriosis
• Maintains bone density better than GnRH agonists during treatment

Common use

Danazol is primarily prescribed for the treatment of endometriosis-associated pain when conventional analgesic and hormonal therapies have proven inadequate. It is considered second-line therapy due to its androgenic side effect profile. In hereditary angioedema, danazol is used for prophylaxis against attacks in patients with documented C1 esterase inhibitor deficiency. Off-label uses include management of fibrocystic breast disease, idiopathic thrombocytopenic purpura, and precocious puberty, though evidence for these indications is less robust. Treatment duration typically ranges from 3-9 months for endometriosis and may be longer term for hereditary angioedema prophylaxis.

Dosage and direction

For endometriosis: Initial dosage typically ranges from 400-800 mg daily divided into two doses. Therapy should begin during menstruation to exclude pregnancy. Dosage may be tapered to the lowest effective dose once amenorrhea is achieved, usually 200-400 mg daily. Treatment beyond 9 months is generally not recommended.

For hereditary angioedema: Initial dose of 200 mg two or three times daily, which may be reduced by 50% or less at 1-3 month intervals depending on response. Maintenance doses as low as 200 mg daily or every other day may be effective.

Administration should be with food to minimize gastrointestinal upset. Regular monitoring of liver function, lipid profile, and hematologic parameters is essential throughout treatment.

Precautions

Liver function tests should be performed before initiation and at regular intervals during therapy due to potential hepatotoxicity. Patients should be monitored for signs of virilization including acne, hirsutism, clitoral enlargement, and voice changes. Lipid profiles should be assessed periodically as danazol may adversely affect cholesterol levels. Blood pressure should be monitored regularly due to potential hypertensive effects. Patients with diabetes should be closely monitored as danazol may decrease glucose tolerance. Caution is advised in patients with cardiac, renal, or hepatic impairment. Use with caution in patients with seizure disorders or migraine headaches as danazol may exacerbate these conditions.

Contraindications

Pregnancy (Category X) or women who may become pregnant during therapy. Nursing mothers. Undiagnosed abnormal genital bleeding. Severe hepatic, renal, or cardiac dysfunction. Porphyria. Known hypersensitivity to danazol or any component of the formulation. Masculinizing effects on a female fetus may occur if pregnancy occurs during treatment.

Possible side effect

Androgenic effects: Acne, oily skin, hirsutism, clitoral hypertrophy, voice deepening (may be irreversible), hair loss Estrogen deficiency: Hot flashes, sweating, vaginal dryness, atrophy, emotional lability Metabolic: Weight gain, fluid retention, elevated liver enzymes, cholestatic jaundice Hematologic: Leukopenia, thrombocytopenia, erythrocytosis Gastrointestinal: Nausea, vomiting, constipation, diarrhea Neurological: Headache, dizziness, fatigue, sleep disturbances Other: Muscle cramps, joint pain, decreased breast size, changes in libido

Drug interaction

Warfarin: Danazol may potentiate anticoagulant effect requiring dosage adjustment Cyclosporine: Increased cyclosporine levels and potential nephrotoxicity Carbamazepine: Possible increased carbamazepine levels Insulin/Oral hypoglycemics: May alter glucose tolerance requiring dosage adjustment Statins: Increased risk of myopathy and rhabdomyolysis CYP3A4 inhibitors/inducers: May alter danazol metabolism Oral contraceptives: May diminish efficacy of both medications

Missed dose

If a dose is missed, it should be taken as soon as remembered unless it is almost time for the next scheduled dose. In that case, the missed dose should be skipped and the regular dosing schedule resumed. Doubling of doses to make up for a missed dose is not recommended. If multiple doses are missed, contact healthcare provider for guidance on resuming therapy.

Overdose

Symptoms of overdose may include nausea, vomiting, dizziness, and headache. There is no specific antidote for danazol overdose. Treatment should be symptomatic and supportive. Gastric lavage may be considered if ingestion was recent. Monitor vital signs and provide appropriate supportive care. Hemodialysis is not likely to be effective due to high protein binding. Contact poison control center for latest guidance.

Storage

Store at room temperature (15-30°C or 59-86°F) in a tightly closed container. Protect from light and moisture. Keep out of reach of children and pets. Do not use after expiration date printed on packaging. Do not transfer capsules to other containers as this may affect stability.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before starting or changing any medication regimen. The prescribing physician should be consulted for specific dosing recommendations and monitoring parameters based on individual patient characteristics. This information may not include all possible uses, directions, precautions, or interactions.

Reviews

Clinical studies demonstrate danazol’s efficacy in reducing endometriosis-associated pain in 70-90% of patients, with significant improvement typically noted within 2-3 months of therapy. For hereditary angioedema prophylaxis, clinical trials show attack frequency reduction of 70-90% in responsive patients. Many specialists note that while side effects can be significant, the therapeutic benefits often outweigh risks for appropriately selected patients. Long-term follow-up studies indicate most androgenic effects are reversible upon discontinuation except for voice changes, which may be permanent. Patient satisfaction surveys show highest approval among those who experienced substantial pain reduction without intolerable side effects.