1. Clinical Overview
Danazol is a synthetic androgen derived from ethisterone. It acts as a pituitary gonadotropin inhibitor and has weak androgenic effects. It is primarily used to treat endometriosis, fibrocystic breast disease, and hereditary angioedema.
| Onset | Duration | Bioavailability |
|---|---|---|
| NA | NA | NA |
2. Mechanism of Action
Danazol binds to androgen, progesterone, and glucocorticoid receptors. Its primary therapeutic action is the dose-dependent suppression of pituitary gonadotropin secretion (LH and FSH), leading to atrophy of endometrial tissue. It also inhibits multiple enzymes in the steroidogenic pathway. It increases the level of C1 esterase inhibitor in patients with hereditary angioedema and reduces immunoglobulin production.
3. Indications & Uses
- Endometriosis (symptom management)
- Fibrocystic breast disease
- Hereditary angioedema (prophylaxis of attacks)
4. Dosage & Administration
Adult Dosage: Varies by indication. For endometriosis: 200-800 mg/day in 2-4 divided doses. For fibrocystic breast disease: 100-400 mg/day in 2 divided doses. For hereditary angioedema: 200 mg 2-3 times daily. Initial dose often starts higher, then reduced for maintenance.
Administration: Administer orally with food to minimize gastrointestinal upset. Dosage should be individualized. Therapy for endometriosis should begin during menstruation. For chronic use, liver function and lipid profile should be monitored.
5. Side Effects
Common side effects may include:
- Weight gain
- Acne, oily skin
- Hirsutism (excessive hair growth)
- Voice deepening (may be irreversible)
- Hot flashes, sweating
- Menstrual irregularities, amenorrhea
- Headache, dizziness
- Muscle cramps
- Nausea
- Edema
- Reduced breast size
- Mood changes, anxiety
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Warfarin / other anticoagulants | Danazol may potentiate anticoagulant effect, increasing risk of bleeding. | Major |
| Cyclosporine, Tacrolimus | Danazol can inhibit metabolism, increasing their blood levels and risk of toxicity. | Major |
| Carbamazepine, Phenytoin | May reduce danazol levels via increased metabolism. | Moderate |
| Insulin, Oral hypoglycemics | Danazol may alter glucose tolerance, requiring dose adjustment. | Moderate |
| Statins (e.g., Lovastatin, Simvastatin) | Increased risk of myopathy/rhabdomyolysis. | Major |
7. Patient Counselling
8. Toxicology & Storage
Overdose: Seek immediate medical attention.
Storage: Store in a cool, dry place.