WARNINGS
See BOX WARNING.
Systemic absorption may occur with the use of ESTRACE (estradiol vaginal cream, USP, 0.01%). The
warnings, precautions, and adverse reactions associated with oral estrogen treatment should be taken
into account.
Cardiovascular Disorders
Estrogen and estrogen/progestin therapy has been associated with an increased risk of cardiovascular
events such as myocardial infarction and stroke, as well as venous thrombosis and pulmonary embolism
(venous thromboembolism or VTE). Should any of these occur or be suspected, estrogens should be
discontinued immediately.
Risk factors for arterial vascular disease (for example, hypertension, diabetes mellitus, tobacco use,
hypercholesterolemia, and obesity) and/or venous thromboembolism (for example, personal history or
family history of VTE, obesity, and systemic lupus erythematosus) should be managed appropriately.
Coronary Heart Disease And Stroke
In the Women’s Health Initiative (WHI) study, an increase in the number of myocardial infarctions and
strokes has been observed in women receiving CE compared to placebo. These observations are
preliminary, and the study is continuing (see CLINICAL PHARMACOLOGY, Clinical Studies ).
In the CE/MPA substudy of WHI, an increased risk of coronary heart disease (CHD) events (defined as
nonfatal myocardial infarction and CHD death) was observed in women receiving CE/MPA compared to
women receiving placebo (37 versus 30 per 10,000 women-years). The increase in risk was observed
in year one and persisted.
In the same substudy of WHI, an increased risk of stroke was observed in women receiving CE/MPA
compared to women receiving placebo (29 versus 21 per 10,000 women-years). The increase in risk
was observed after the first year and persisted.
In postmenopausal women with documented heart disease (n = 2,763, average age 66.7 years) a
controlled clinical trial of secondary prevention of cardiovascular disease (Heart and
Estrogen/Progestin Replacement Study; HERS) treatment with CE/MPA (0.625 mg/2.5 mg per day)
demonstrated no cardiovascular benefit. During an average follow-up of 4.1 years, treatment with
CE/MPA did not reduce the overall rate of CHD events in postmenopausal women with established
coronary heart disease. There were more CHD events in the CE/MPA-treated group than in the placebo
group in year 1, but not during the subsequent years. Two thousand three hundred and twenty one women
from the original HERS trial agreed to participate in an open label extension of HERS, HERS II.
Average follow-up in HERS II was an additional 2.7 years, for a total of 6.8 years overall. Rates of
CHD events were comparable among women in the CE/MPA group and the placebo group in HERS,
HERS II, and overall.
Large doses of estrogen (5 mg conjugated estrogens per day), comparable to those used to treat cancer
of the prostate and breast, have been shown in a large prospective clinical trial in men to increase the
risks of nonfatal myocardial infarction, pulmonary embolism, and thrombophlebitis.
Venous Thromboembolism (VTE)
In the Women’s Health Initiative (WHI) study, an increase in VTE has been observed in women
receiving CE compared to placebo. These observations are preliminary, and the study is continuing (see CLINICAL PHARMACOLOGY, Clinical Studies ).
In the CE/MPA substudy of WHI, a 2-fold greater rate of VTE, including deep venous thrombosis and
pulmonary embolism, was observed in women receiving CE/MPA compared to women receiving
placebo. The rate of VTE was 34 per 10,000 women-years in the CE/MPA group compared to 16 per
10,000 women-years in the placebo group. The increase in VTE risk was observed during the first year
and persisted.
If feasible, estrogens should be discontinued at least 4 to 6 weeks before surgery of the type
associated with an increased risk of thromboembolism, or during periods of prolonged immobilization.
Malignant Neoplasms
Endometrial Cancer
The use of unopposed estrogens in women with intact uteri has been associated with an increased risk
of endometrial cancer. The reported endometrial cancer risk among unopposed estrogen users is about
2- to 12-fold greater than in non-users, and appears dependent on duration of treatment and on estrogen
dose. Most studies show no significant increased risk associated with use of estrogens for less than
one year. The greatest risk appears associated with prolonged use, with increased risks of 15- to 24-
fold for five to ten years or more and this risk has been shown to persist for at least 8 to 15 years after
estrogen therapy is discontinued.
Clinical surveillance of all women taking estrogen/progestin combinations is important. Adequate
diagnostic measures, including endometrial sampling when indicated, should be undertaken to rule out
malignancy in all cases of undiagnosed persistent or recurring abnormal vaginal bleeding. There is no
evidence that the use of natural estrogens results in a different endometrial risk profile than synthetic
estrogens of equivalent estrogen dose. Adding a progestin to estrogen therapy has been shown to
reduce the risk of endometrial hyperplasia, which may be a precursor to endometrial cancer.
Breast Cancer
The use of estrogens and progestins by postmenopausal women has been reported to increase the risk
of breast cancer. The most important randomized clinical trial providing information about this issue is
the Women’s Health Initiative (WHI) substudy of CE/MPA (see CLINICAL PHARMACOLOGY, Clinical Studies). The results from observational studies are generally consistent with those of the
WHI clinical trial and report no significant variation in the risk of breast cancer among different
estrogens or progestins, doses, or routes of administration.
The CE/MPA substudy of WHI reported an increased risk of breast cancer in women who took
CE/MPA for a mean follow-up of 5.6 years. Observational studies have also reported an increased risk
for estrogen/progestin combination therapy, and a smaller increased risk for estrogen-alone therapy,
after several years of use. In the WHI trial and from observational studies, the excess risk increased
with duration of use. From observational studies, the risk appeared to return to baseline in about five
years after stopping treatment. In addition, observational studies suggest that the risk of breast cancer
was greater, and became apparent earlier, with estrogen/progestin combination therapy as compared to
estrogen-alone therapy.
In the CE/MPA substudy, 26 percent of the women reported prior use of estrogen-alone and/or
estrogen/progestin combination hormone therapy. After a mean follow-up of 5.6 years during the
clinical trial, the overall relative risk of invasive breast cancer was 1.24 (95 percent confidence interval
1.01 to 1.54), and the overall absolute risk was 41 versus 33 cases per 10,000 women-years for
CE/MPA compared with placebo. Among women who reported prior use of hormone therapy, the
relative risk of invasive breast cancer was 1.86, and the absolute risk was 46 versus 25 cases per
10,000 women-years for CE/MPA compared with placebo. Among women who reported no prior use
of hormone therapy, the relative risk of invasive breast cancer was 1.09, and the absolute risk was 40
versus 36 cases per 10,000 women-years for CE/MPA compared with placebo. In the same substudy,
invasive breast cancers were larger and diagnosed at a more advanced stage in the CE/MPA group
compared with the placebo group. Metastatic disease was rare with no apparent difference between the
two groups. Other prognostic factors such as histologic subtype, grade and hormone receptor status did
not differ between the groups.
The use of estrogen-plus-progestin has been reported to result in an increase in abnormal mammograms
requiring further evaluation. All women should receive yearly breast examinations by a healthcare
provider and perform monthly breast self-examinations. In addition, mammography examinations should
be scheduled based on patient age, risk factors, and prior mammogram results.
Dementia
In the Women’s Health Initiative Memory Study (WHIMS), 4,532 generally healthy postmenopausal
women 65 years of age and older were studied, of whom 35 percent were 70 to 74 years of age and 18
percent were 75 or older. After an average follow-up of 4 years, 40 women being treated with
CE/MPA (1.8 percent, n = 2,229) and 21 women in the placebo group (0.9 percent, n = 2,303) received
diagnoses of probable dementia. The relative risk for CE/MPA versus placebo was 2.05 (95 percent
confidence interval 1.21 to 3.48), and was similar for women with and without histories of menopausal
hormone use before WHIMS. The absolute risk of probable dementia for CE/MPA versus placebo was
45 versus 22 cases per 10,000 women-years, and the absolute excess risk for CE/MPA was 23 cases
per 10,000 women-years. It is unknown whether these findings apply to younger postmenopausal
women (see CLINICAL PHARMACOLOGY, Clinical Studies and PRECAUTIONS, Geriatric
Use).
It is unknown whether these findings apply to estrogen-alone therapy.
Gallbladder Disease
A 2- to 4-fold increase in the risk of gallbladder disease requiring surgery in postmenopausal women
receiving estrogens has been reported.
Hypercalcemia
Estrogen administration may lead to severe hypercalcemia in patients with breast cancer and bone
metastases. If hypercalcemia occurs, use of the drug should be stopped and appropriate measures taken
to reduce the serum calcium level.
Visual Abnormalities
Retinal vascular thrombosis has been reported in patients receiving estrogens. Discontinue medication
pending examination if there is sudden partial or complete loss of vision, or a sudden onset of
proptosis, diplopia, or migraine. If examination reveals papilledema or retinal vascular lesions,
estrogens should be permanently discontinued.