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Danazol for Endometriosis


Generic Name

Danazol is a synthetic form of the male hormone testosterone.

How It Works

Danazol is a drug that lowers estrogen levels and increases androgen levels. This puts the body in a state that is like menopause and can cause some male physical traits, as well. As a result, danazol:

Why It Is Used

Danazol is sometimes used to treat endometriosis, usually when all other hormone therapies have not helped. Danazol can:

  • Relieve pain.
  • Prevent endometriosis from getting worse.
  • Reduce the size of endometriosis implants.
  • Be used to shrink implants before surgery, which can help prevent internal scarring from the surgery.

Danazol is not widely used to treat endometriosis and other estrogen-related conditions, because it can cause serious side effects. Because of these serious side effects, such as increased cholesterol levels, danazol use is limited to 6 to 9 months at a time. Danazol may not be appropriate if you already have a high risk for developing increased cholesterol levels or liver disease.

Reasons not to use danazol include:

  • Undiagnosed abnormal vaginal bleeding.
  • Chronic liver, kidney, or heart disease, which can become worse with danazol therapy.
  • Pregnancy or possibility of pregnancy during treatment (danazol can harm a fetus).
  • Breast-feeding.
  • Inherited disorder of skin pigment (porphyria).

How Well It Works

Up to 90 out of 100 women who use danazol report improvement in symptoms of endometriosis.1 Relief is likely to be noticed within a few months after starting treatment. Pain relief typically lasts for 6 to 12 months after stopping treatment.

Like all hormone therapies and surgery for endometriosis, danazol does not cure the disease.

Danazol does not improve infertility caused by endometriosis.

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Call911or other emergency services right away if you have:

Call your doctor if you have:

Common side effects of this medicine include:

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Danazol may cause your skin to be more sensitive to sunlight. When you are taking this medicine:

  • Stay out of the sun, if possible.
  • Wear long pants, long-sleeved shirts, and hats, if possible.
  • Use sunscreen with an SPF that your doctor recommends.
  • Call your doctor if you have a severe reaction after being in the sun.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Advice for women

Do not use this medicine if you are pregnant or planning to get pregnant. If you need to use this medicine, talk to your doctor about how you can prevent pregnancy.


Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.


  1. Lobo RA (2012). Endometriosis: Etiology, pathology, diagnosis, management. In GM Lentz et al., eds., Comprehensive Gynecology, 6th ed., pp. 433–452. Philadelphia: Mosby.

By Healthwise Staff
Primary Medical Reviewer Sarah Marshall, MD - Family Medicine
Specialist Medical Reviewer Kirtly Jones, MD - Obstetrics and Gynecology
Current as of March 12, 2014

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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