WARNINGS
Included as part of the PRECAUTIONS section.
See BOXED WARNINGS.
Cardiovascular Disorders
An increased risk of PE, DVT, stroke, and MI has been
reported with estrogen plus progestin therapy. Should any of these events occur
or be suspected, estrogen plus progestin therapy should be discontinued
immediately.
Risk factors for arterial vascular disease (for example,
hypertension, diabetes mellitus, tobacco use, hypercholesterolemia, and obesity)
and/or venous thromboembolism (VTE) (for example, personal history or family
history of VTE, obesity, and systemic lupus erythematosus) should be managed appropriately.
Stroke
In the WHI estrogen plus progestin substudy, a
statistically significant increased risk of stroke was reported in women 50 to
79 years of age receiving CE (0.625 mg) plus MPA (2.5 mg) compared to women in
the same age group receiving placebo (33 versus 25 per 10,000 women-years).
(See Clinical Studies.) The increase in risk was demonstrated after the
first year and persisted. Should a stroke occur or be suspected, estrogen plus
progestin therapy should be discontinued immediately.
Coronary Heart Disease
In the WHI estrogen plus progestin substudy, there was a
statistically non-significant increased risk of CHD events reported in women
receiving daily CE (0.625 mg) plus MPA (2.5 mg) compared to women receiving
placebo (41 versus 34 per 10,000 women-years). An increase in relative risk was
demonstrated in year 1, and a trend toward decreasing relative risk was
reported in years 2 through 5.
In postmenopausal women with documented heart disease (n
= 2,763, average 66.7 years of age), in a controlled clinical trial of
secondary prevention of cardiovascular disease (Heart and Estrogen/Progestin
Replacement Study [HERS]), treatment with daily CE (0.625 mg) plus MPA (2.5mg) demonstrated
no cardiovascular benefit. During an average follow-up of 4.1 years, treatment
with CE plus 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 plus MPA-treated group than in the placebo group in year 1, but not
during the subsequent years. Two thousand three hundred and twentyone (2,321)
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 plus MPA group and the placebo group in HERS, HERS II,
and overall.
Venous Thromboembolism
In the WHI estrogen plus progestin substudy, a
statistically significant 2-fold greater rate of VTE (DVT and PE) was reported
in women receiving daily CE (0.625 mg) plus MPA (2.5 mg) compared to women receiving
placebo (35 versus 17 per 10,000 women-years). Statistically significant
increases in risk for both DVT (26 versus 13 per 10,000 women-years) and PE (18
versus 8 per 10,000 women-years) were also demonstrated. The increase in VTE
risk was demonstrated during the first year and persisted. (See Clinical
Studies.) Should a VTE occur or be suspected, estrogen plus progestin
therapy should be discontinued immediately.
If feasible, estrogens plus progestins 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
Breast Cancer
The most important randomized clinical trial providing
information about breast cancer in estrogen plus progestin users is the WHI
substudy of daily CE (0.625 mg) plus MPA (2.5 mg). After a mean follow-up of
5.6 years, the estrogen plus progestin substudy reported an increased risk of
invasive breast cancer in women who took daily CE plus MPA.
In this substudy, prior use of estrogen-alone or estrogen
plus progestin therapy was reported by 26 percent of the women. The relative
risk of invasive breast cancer was 1.24, and the absolute risk was 41 versus 33
cases per 10,000 women-years, for CE plus 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 plus 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 plus MPA compared with placebo. In the same substudy, invasive breast
cancers were larger, were more likely to be node positive, and were diagnosed
at a more advanced stage in the CE (0.625 mg) plus MPA (2.5 mg) 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. (See Clinical
Studies.)
Consistent with the WHI clinical trial, observational
studies have also reported an increased risk of breast cancer for estrogen plus
progestin therapy, and a smaller risk for estrogen-alone therapy, after several
years of use. The risk increased with duration of use, and appeared to return
to baseline over about 5 years after stopping treatment (only the observational
studies have substantial data on risk after stopping). Observational studies
also suggest that the risk of breast cancer was greater, and became apparent
earlier, with estrogen plus progestin therapy as compared to estrogen-alone therapy.
However, these studies have not found significant variation in the risk of
breast cancer among different estrogen plus progestin combinations, or routes
of administration.
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.
Endometrial Cancer
An increased risk of endometrial cancer has been reported
with the use of unopposed estrogen therapy in women with a uterus. The reported
endometrial cancer risk among unopposed estrogen users is about 2 to 12 times
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 the use of estrogens for less than 1 year. The greatest risk appears associated
with prolonged use, with increased risks of 15- to 24-fold for 5 to 10 years or
more. This risk has been shown to persist for at least 8 to 15 years after
estrogen therapy is discontinued.
Clinical surveillance of all women using estrogen plus
progestin therapy 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 genital 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.
Ovarian Cancer
The WHI estrogen plus progestin substudy reported a
statistically non-significant increased risk of ovarian cancer. After an
average follow-up of 5.6 years, the relative risk for ovarian cancer for CE plus
MPA versus placebo was 1.58 (95 percent CI, 0.77–3.24). The absolute risk for
CE plus MPA was 4 versus 3 cases per 10,000 women-years. In some epidemiologic
studies, the use of estrogen plus progestin and estrogen-only products, in
particular for 5 or more years, has been associated with increased risk of
ovarian cancer. However, the duration of exposure associated with increased
risk is not consistent across all epidemiologic studies and some report no
association.
Probable Dementia
In the WHIMS estrogen plus progestin ancillary study of
WHI, a population of 4,532 postmenopausal women aged 65 to 79 years was
randomized to daily CE (0.625 mg) plus MPA (2.5 mg) or placebo. After an
average follow-up of 4 years, 40 women in the CE plus MPA group and 21 women in
the placebo group were diagnosed with probable dementia. The relative risk of
probable dementia for CE plus MPA versus placebo was 2.05 (95 percent CI,
1.21–3.48). The absolute risk of probable dementia for CE plus MPA versus
placebo was 45 versus 22 cases per 10,000 women-years. It is unknown whether
these findings apply to younger postmenopausal women. (See Clinical Studies
and PRECAUTIONS, Geriatric Use.)
Visual Abnormalities
Discontinue estrogen plus progestin therapy 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, estrogen plus progestin therapy should be permanently
discontinued.