Indications
Danazol is a synthetic hormone medicine used under specialist care for endometriosis (womb-lining tissue growing outside the womb, causing pain), painful benign breast lumps and breast pain (fibrocystic breast disease), and to prevent attacks of hereditary angioedema (repeated swelling of the face, throat or gut). It is sometimes used for certain blood disorders such as low platelets, as decided by a specialist.
How It Works
Danazol acts on the pituitary gland in the brain and reduces the release of hormones that stimulate the ovaries. This lowers oestrogen levels and stops ovulation and periods, so endometriosis tissue shrinks and breast symptoms ease. It also has weak male-hormone (androgen) effects. In hereditary angioedema, it raises the level of a protein (C1 esterase inhibitor) that helps prevent swelling attacks.
Dosage and Administration
Take exactly as prescribed. The dose and length of treatment depend on the condition and are set by the specialist, usually starting during a period after a negative pregnancy test. Capsules are taken by mouth, often in divided doses. Do not stop or change the dose without advice.
Interactions
Danazol can increase the effect of Warfarin and raise levels of Carbamazepine, Ciclosporin and Tacrolimus. Using it with Simvastatin, Atorvastatin or Lovastatin raises the risk of serious muscle damage. It may change blood sugar control and affect the dose of Insulin or other diabetes medicines. Hormonal contraceptives should not be used during treatment; use a barrier method instead.
Contraindications
Do not use in pregnancy or breastfeeding, or if you have undiagnosed vaginal bleeding, severe liver, kidney or heart disease, a history of blood clots or stroke, porphyria, a hormone-dependent tumour, or an allergy to Danazol.
Side Effects
Common side effects include weight gain, fluid retention, acne, oily skin, increased hair growth, deepening of the voice (which may be permanent), hot flushes, vaginal dryness, smaller breasts, irregular spotting, muscle cramps, headache and mood changes. It can affect liver tests and cholesterol.
Get urgent medical help if you have yellowing of the skin or eyes, severe stomach pain, signs of a blood clot (pain or swelling in one leg, chest pain, sudden breathlessness, weakness on one side, slurred speech), severe headache with vision problems, or a serious allergic reaction. Tell your doctor promptly about voice changes so treatment can be reviewed.
Pregnancy and Lactation
Danazol can cause male-type changes in a female unborn baby. It must not be used in pregnancy; a pregnancy test is done before starting and a non-hormonal barrier method of contraception must be used during treatment. Do not breastfeed while taking it.
Precautions and Warnings
Liver function, blood counts and lipids are checked during treatment. Use with care in epilepsy, migraine, diabetes, high blood pressure and heart or kidney problems, because fluid retention may worsen them. Long-term use needs regular review.
Overdose
Overdose is unlikely to cause immediate serious harm, but contact a doctor or the nearest hospital for advice.
Therapeutic Class
Synthetic steroid hormone, gonadotropin inhibitor.
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.