Recommended Topic Related To:


"Nov. 20, 2012 -- Although mammograms remain the gold standard for breast cancer screening, they are not the perfect test.

They don't find up to 30% of cancers, and they often find something that may be suspicious for cancer but really"...


Discontinued Warning IconPlease Note: This Brand Name drug is no longer available in the US.
(Generic versions may still be available.)

Teslac Patient Information Including Side Effects

Brand Names: Teslac

Generic Name: testolactone (Pronunciation: test O lack tone)

What is testolactone (Teslac)?

Testolactone blocks the production of the hormone estrogen. Certain types of breast cancer require estrogen to grow.

Testolactone is used to treat some types of breast cancer.

Testolactone may also be used for purposes other than those listed in this medication guide.

What are the possible side effects of testolactone (Teslac)?

Stop taking testolactone and seek emergency medical attention or contact your doctor immediately if you experience any of the following serious side effects:

  • an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);
  • new breast lumps;
  • bone pain;
  • menstrual changes, abnormal vaginal bleeding, vaginal discharge, or pelvic pain or pressure; or
  • excessive nausea, vomiting, or thirst.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

Read the Teslac (testolactone) Side Effects Center for a complete guide to possible side effects

What is the most important information I should know about testolactone (Teslac)?

Testolactone should not be used for the treatment of men with breast cancer or in patients with a history of allergic reactions to the drug.

Side Effects Centers

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Breast Cancer

Find support and advances in treatment.