Prefest
FDA Approves Osphena for Postmenopausal Women Experiencing Pain During Sex »
"The U.S. Food and Drug Administration today approved Osphena (ospemifene) to treat women experiencing moderate to severe dyspareunia (pain during sexual intercourse), a symptom of vulvar and vaginal atrophy due to menopause.
Dyspareunia"...
Read the FDA Approves Osphena for Postmenopausal Women Experiencing Pain During Sex article »
Prefest
PREFEST™
(estradiol/norgestimate) Tablets
WARNING
Estrogens and progestins should not be used for the prevention of cardiovascular disease. (See WARNINGS, Cardiovascular disorders.)
The Women's Health Initiative (WHI) study reported increased risks of myocardial infarction, stroke, invasive breast cancer, pulmonary emboli, and deep vein thrombosis in postmenopausal women (50 to 79 years of age) during 5 years of treatment with oral conjugated estrogens (CE 0.625 mg) combined with medroxyprogesterone acetate (MPA 2.5 mg) relative to placebo. (See CLINICAL PHARMACOLOGY, Clinical Studies.)
The Women's Health Initiative Memory Study (WHIMS), a substudy of WHI, reported increased risk of developing probable dementia in postmenopausal women 65 years of age or older during 4 years of treatment with oral conjugated estrogens plus medroxyprogesterone acetate relative to placebo. It is unknown whether this finding applies to younger postmenopausal women or to women taking estrogen alone therapy. (See CLINICAL PHARMACOLOGY, Clinical Studies.)
Other doses of oral conjugated estrogens with medroxyprogesterone acetate, and other combinations and dosage forms of estrogens and progestins were not studied in the WHI clinical trials and, in the absence of comparable data, these risks should be assumed to be similar. Because of these risks, estrogens with or without progestins should be prescribed at the lowest effective doses and for the shortest duration consistent with treatment goals and risks for the individual woman.
DRUG DESCRIPTION
The PREFEST (estradiol, norgestimate) regimen provides for a single oral tablet to be taken once daily. The pink tablet containing 1.0 mg estradiol is taken on days one through three of therapy; the white tablet containing 1.0 mg estradiol and 0.09 mg norgestimate is taken on days four through six of therapy. This pattern is then repeated continuously to produce the constant estrogen/intermittent progestogen regimen of PREFEST (estradiol, norgestimate) .
The estrogenic component of PREFEST (estradiol, norgestimate) is estradiol, USP. It is a white, crystalline solid, chemically described as estra-1,3,5(10)-triene-3,17β-diol. It has an empirical formula of C18H24O2 and molecular weight of 272.39. The structural formula is:
![]() |
The progestational component of PREFEST (estradiol, norgestimate) is micronized norgestimate, a white powder which is chemically described as 18,19-dinor-17-pregn-4-en-20-yn-3-one, 17-(acetyloxy)-13-ethyl-,oxime,(17α)-(+)-. It has an empirical formula of C23H31NO3 and a molecular weight of 369.50. The structural formula is:
![]() |
Each tablet for oral administration contains 1.0 mg estradiol alone or 1.0 mg estradiol and 0.09 mg of norgestimate, and the following inactive ingredients: croscarmellose sodium, microcrystalline cellulose, magnesium stearate, ferric oxide red, and lactose monohydrate.
What are the possible side effects of estradiol and norgestimate ()?
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using this medication and call your doctor at once if you have a serious side effect such as:
- unusual vaginal bleeding (especially if you are past menopause);
- chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling;
- sudden numbness or weakness, especially on one side of the body;
- sudden severe headache, confusion, problems...
Read All Potential Side Effects and See Pictures of Prefest »
What are the precautions when taking estradiol, norgestimate (Prefest)?
Before taking this medication, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: vaginal bleeding of unknown cause, certain cancers (such as breast cancer, cancer of the uterus/ovaries), blood clots, stroke, heart disease (such as heart attack), liver disease, kidney disease, family medical history (especially breast lumps, cancer, blood clots, angioedema), blood clotting disorders (such as protein C or protein S deficiency), high blood pressure, diabetes, high blood cholesterol/triglyceride levels,...
Last reviewed on RxList: 3/4/2009
This monograph has been modified to include the generic and brand name in many instances.
Additional Prefest Information
Prefest - User Reviews
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.
Women's Health
Find out what women really need.








