Conjugated Estrogens (Cenestin, Enjuvia, Estrace, and Others) (cont.)

Pharmacy Author:
Medical and Pharmacy Editor:

The Women's Health Initiative found that postmenopausal women (50 to 79 years old) taking conjugated estrogens, 0.625 mg daily, in combination with medroxyprogesterone (Provera, Depo-Provera, Depo-Sub Q Provera 104), 2.5 mg daily, for five years, had an increased risk of heart attacks, stroke, breast cancer, and blood clots, while postmenopausal women taking conjugated estrogens without progesterone experienced only increased strokes but not increased blood clots, heart disease, or breast cancer.

There was an increased risk of impaired cognition and/or dementia among women over age 65 treated with either estrogens or estrogens and medroxyprogesterone.

What drugs interact with conjugated estrogens?

Medications like St. John's Wort, phenobarbital, carbamazepine (Tegretol, Tegretol XR, Equetro, Carbatrol), and rifampin (Rifadin) can accelerate the breakdown of conjugated estrogens, leading to low levels of absorbed drug and reduced effectiveness. Grapefruit juice and medications like erythromycin, clarithromycin (Biaxin, Biaxin XL), ketoconazole (Nizoral, Extina, Xolegel, Kuric), and ritonavir can slow down the breakdown of conjugated estrogens in the liver, leading to increased levels of estrogens and increased estrogen side effects.

What formulations of conjugated estrogens are available?

Medically Reviewed by a Doctor on 7/2/2014


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.

Pill Finder Tool

Need help identifying pills and medications?
Use the pill identifier tool on RxList.


Back to Medications Index