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(estradiol/norethindrone acetate transdermal system)


Estrogens and progestins should not be used for the prevention of cardiovascular disease or dementia. (See WARNINGS, Cardiovascular disorders and Dementia.) The Womens 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 equine estrogens (CE 0.625 mg) combined with medroxyprogesterone acetate (MPA 2.5 mg) relative to placebo (See CLINICAL PHARMACOLOGY, Clinical Studies and WARNINGS, Cardiovascular disorders and Malignant neoplasms, Breast cancer.) The Womens 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. (See CLINICAL PHARMACOLOGY, Clinical Studies, WARNINGS, Dementia and PRECAUTIONS, Geriatric Use.) 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.


CombiPatch ® (estradiol/norethindrone acetate transdermal system) is an adhesive-based matrix transdermal patch designed to release both estradiol and norethindrone acetate (NETA), a progestational agent, continuously upon application to intact skin.

Two systems are available, providing the following delivery rates of estradiol and norethindrone acetate.

System Size
Estradiol (mg)
NETA1 (mg)
Nominal Delivery Rate2 (mg per day) Estradiol / NETA
9 sq cm round
0.05 / 0.14
16 sq cm round
0.05 / 0.25
1 NETA = norethindrone acetate
2 Based on in vivo/in vitro flux data, delivery of both components per day via skin of average permeability (interindividual variation in skin permeability is approximately 20%).

Estradiol USP (estradiol) is a white to creamy white, odorless, crystalline powder, chemically described as estra-1,3,5(10)-triene-3,17b -diol. The molecular weight of estradiol is 272.39 and the molecular formula is C18H24O2.

Norethindrone acetate USP is a white to creamy white, odorless, crystalline powder, chemically described as 17-hydroxy-19-nor-17a -pregn-4-en-20-yn-3-one acetate. The molecular weight of norethindrone acetate is 340.47 and the molecular formula is C22H28O3.

The structural formulas for estradiol and norethindrone acetate are

CombiPatch (estradiol, norethindrone acetate transdermal system) transdermal systems are comprised of three layers. Proceeding from the visible surface toward the surface attached to the skin, these layers are (1) a translucent polyolefin film backing, (2) an adhesive layer containing estradiol, norethindrone acetate, acrylic adhesive, silicone adhesive, oleyl alcohol, oleic acid NF, povidone USP and dipropylene glycol, and (3) a polyester release protective liner, which is attached to the adhesive surface and must be removed before the system can be used.

The active components of the system are estradiol USP and norethindrone acetate USP. The remaining components of the system are pharmacologically inactive.

What are the possible side effects of estradiol and norethindrone (Combipatch)?

Treatment with estrogens long-term may increase the risk of heart attack, stroke, breast cancer, and blood clots in the lungs or legs. Because of these risks, you should contact your doctor or healthcare provider to discuss your individual risks and benefits before using estradiol and norethindrone long-term. You should also talk to your doctor or healthcare provider on a regular basis (for example, every 3-6 months) about whether you should continue this treatment.

If you experience any of the following serious side effects, stop using estradiol and norethindrone...

Read All Potential Side Effects and See Pictures of CombiPatch »

What are the precautions when taking estradiol, norethindrone acetate transdermal system (CombiPatch)?

Before using this medication, tell your doctor or pharmacist if you are allergic to estradiol or norethindrone; 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...

Read All Potential Precautions of CombiPatch »

Last reviewed on RxList: 10/5/2006
This monograph has been modified to include the generic and brand name in many instances.


CombiPatch - User Reviews

CombiPatch User Reviews

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