How does this medication work? What will it do for me?

Danazol is in the class of medications known as pituitary gonadotropin inhibitors. It is used to treat endometriosis and to relieve pain caused by benign (noncancerous) fibrocystic breast disease.

In the treatment of endometriosis, danazol affects hormone levels resulting in changes in the endometrial tissue (that usually lines the uterus but exists outside of the uterus in endometriosis) so that these tissues become inactive and decrease in size.

In the treatment of fibrocystic breast disease, danazol results in the relief of pain and tenderness and decreases breast nodules. It should only be used for fibrocystic breast disease if other treatments do not work or cannot be taken.

Danazol is not recommended to be used for more than 6 months. The action of danazol on hormone regulation is reversible and normal menstruation returns within 2 to 3 months of stopping therapy.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

50 mg
Each hard pink gelatin capsule, with "D50" on the cap and on the body contains danazol 50 mg. Nonmedicinal ingredients: maize starch, gelatin, lactose monohydrate, magnesium stearate, red iron oxide, talc, and titanium dioxide. Bisulfite-, gluten-, sucrose-, and tartrazine-free.

100 mg
Each hard bicolour (grey cap/white body) gelatin capsule, with "D100" on the cap and on the body contains danazol 100 mg. Nonmedicinal ingredients: black iron oxide, maize starch, gelatin, lactose monohydrate, magnesium stearate, talc, and titanium dioxide. Bisulfite-, gluten-, sucrose-, and tartrazine-free.

200 mg
Each hard white gelatin capsule, with "D200" on the cap and on the body contains danazol 200 mg. Nonmedicinal ingredients: cornstarch, gelatin, lactose, magnesium stearate, talc, and titanium dioxide. Bisulfite-, gluten-, sucrose-, and tartrazine-free.

How should I use this medication?

Danazol therapy should be started during menstruation unless a reliable pregnancy test has been performed to ensure that you are not pregnant. An effective nonhormonal method of birth control should be used during therapy with danazol.

The usual dosage range for treating endometriosis is 200 mg to 800 mg taken daily in 2 to 4 divided doses without interruption for 3 to 6 months. The recommended maximum duration of therapy is 6 months.

The usual dosage range for treating fibrocystic breast disease is 100 mg to 400 mg taken daily in 2 divided doses. Symptoms should decrease within 30 to 40 days. The recommended maximum duration of therapy is 6 months. Treatment should stop before the end of the 6 months if the symptoms disappear.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one.If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take this medication if you:

  • are allergic to danazol or any ingredients of the medication
  • are breast-feeding
  • are pregnant
  • have a tumour dependent on androgen (male sex hormone)
  • have abnormal vaginal bleeding not diagnosed by a doctor
  • have genital cancer
  • have kidney, liver, or heart problems
  • have or have had problems with blood clots forming in the blood vessels
  • have porphyria

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • acne
  • fluid retention or puffiness in the hands, ankles, or feet
  • flushing or redness of skin
  • increased oiliness of hair or skin
  • mood or mental changes
  • nervousness
  • puffiness of the face
  • sweating
  • vaginal burning, dryness, or itching
  • vaginal spotting or bleeding

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • abdominal pain
  • changes in vision
  • decrease in breast size
  • deepening of the voice
  • headache (persistent)
  • increase in size of the clitoris
  • irregular menstrual periods
  • mild growth of body hair
  • signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
  • signs of pancreas problems (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
  • weight gain

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • seizures
  • signs of a blood clot in blood vessels (e.g., sudden vision change or dizziness, chest pain, pain and swelling in one leg muscle)
  • signs of a severe skin reaction (e.g., blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Altered hormone levels: Danazol treatment causes considerable changes in hormone levels and may result in such side effects as acne, weight gain, irregular menstrual patterns or no menstruation, and the development of male characteristics (see below). If these are bothersome, discuss your concerns with your doctor.

Blood clots: This medication may increase the chance of blood clot formation, causing reduced blood flow to organs or the extremities.

If you have a history of clotting, you may be at increased risk of experiencing blood-clot-related problems such as heart attack, stroke, or clots in the deep veins of your leg. Discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience symptoms such as sharp pain and swelling in the leg, difficulty breathing, chest pain, blurred vision, or difficulty speaking, contact your doctor immediately.

Breast cancer: Danazol is not intended to treat symptoms of breast cancer. Before starting danazol therapy for the treatment of fibrocystic breast disease, your doctor should exclude the possibility of breast cancer. Any nodules that do not decrease in size after 2 or 3 months should be discussed with your doctor.

Cholesterol levels: People taking danazol may experience changes to their blood cholesterol levels. If you have abnormal cholesterol levels or a history of elevated cholesterol, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Development of male characteristics: Women should watch closely for the development of male characteristics such as hoarseness or deepening of the voice, clitoral thickening, and more than minimal growth of body hair. These effects may not be reversible. If these effects occur, contact your doctor to discuss further therapy.

Diabetes: Danazol may interfere with blood glucose control. People with diabetes should monitor their blood glucose closely and report any abnormalities to their doctor. Antidiabetes medications may need to be adjusted.

Heart disease and blood pressure: Danazol may cause fluid retention, increased blood pressure and possibly blood clots. If you have a history of blood clots, high blood pressure, or other heart disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Kidney function: If you have kidney disease or reduced kidney function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. While you are taking danazol, your doctor may order blood tests to check how well your kidneys are working.

Liver function: Danazol can cause decreased liver function and may cause liver failure, when taken at normal doses. If you have liver disease or reduced liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. While you are taking danazol, your doctor may order blood tests to check how well your liver is working.

If you experience signs of decreased liver function, such as nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, or pale stools, contact your doctor as soon as possible.

Migraine headache: People taking danazol may experience increased migraine headaches. If you experience migraine headaches while taking danazol, contact your doctor. People who experience migraine headaches before taking danazol may experience an increase in the frequency of migraine headaches. If you experience migraine headaches, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Ovarian cancer: Danazol may increase the risk of ovarian cancer in people treated for endometriosis.

Seizure disorder: Danazol may affect medications taken to control seizures. If you have epilepsy or another seizure disorder, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Thyroid tests: Danazol may interfere with laboratory tests used to monitor thyroid function.

Pregnancy: If taken during pregnancy, danazol may be harmful to the unborn child. Danazol should be started during menstruation and an effective nonhormonal method of birth control should be used while taking it. If you think you may be pregnant, stop taking danazol and discuss the risks with your doctor.

Breast-feeding: Danazol may cause harm to an infant if it is taken by a breast-feeding mother. It must not be taken by women who are breast-feeding.

Children: The safety and effectiveness of this medication have not been established for use by children.

What other drugs could interact with this medication?

There may be an interaction between danazol and any of the following:

  • aripiprazole
  • carbamazepine
  • corticosteroids (e.g., dexamethasone, hydrocortisone, prednisone)
  • cyclosporine
  • diabetes medications (e.g., chlorpropamide, glipizide, glyburide, insulin, metformin, nateglinide, rosiglitazone)
  • dofetilide
  • high blood pressure medications
  • hydrocodone
  • lomitapide
  • phenobarbital
  • phenytoin
  • pimozide
  • "statin" cholesterol lowering medications (e.g., atorvastatin, pravastatin)
  • tacrolimus
  • vitamin D analogues (e.g., alfacalcidol, calcitriol, cholecalciferol)
  • warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.