WARNINGS
See BOXED WARNINGS.
Premarin Intravenous for injection is indicated for
short-term use. However, warnings, precautions and adverse reactions associated
with oral Premarin treatment should be taken into account.
Cardiovascular Disorders
An increased risk of stroke and DVT has been reported with
estrogen-alone therapy.
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
with or without 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-alone substudy, a statistically
significant increased risk of stroke was reported in women 50 to 79 years of
age receiving daily CE (0.625 mg)-alone compared to women in the same age group
receiving placebo (45 versus 33 per 10,000 women-years). (See Clinical
Studies.) The increase in risk was demonstrated in year 1 and persisted.
Should a stroke occur or be suspected, estrogen-alone therapy should be
discontinued immediately.
Subgroup analyses of women 50 to 59 years of age suggest no
increased risk of stroke for those women receiving CE (0.625 mg)-alone versus
those receiving placebo (18 versus 21 per 10,000 women-years).
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 daily 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-alone substudy, no overall effect on CHD
events (defined as nonfatal MI, silent MI, or CHD death) was reported in women
receiving estrogen-alone compared to placebo. (See Clinical Studies.)
In the WHI estrogen plus progestin substudy, there was a
non-statistically 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/MPA 2.5 mg 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
one, but not during the subsequent years. Two thousand three hundred and
twenty-one (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
the HERS, the HERS II, and overall.
Venous thromboembolism
In the WHI estrogen-alone substudy, the risk of VTE (DVT and
PE), was increased for women receiving daily CE (0.625 mg)-alone compared to
placebo (30 versus 22 per 10,000 women-years), although only the increased risk
of DVT reached statistical significance (23 versus 15 per 10,000 women-years).
The increase in VTE risk was demonstrated during the first 2 years. (See Clinical
Studies.) Should a VTE occur or be suspected, estrogen-alone therapy should
be discontinued immediately.
In the WHI estrogen plus progestin substudy, a statistically
significant 2-fold greater rate of VTE 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.
Malignant Neoplasms
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 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 and this risk has been shown to persist for at least 8 to 15
years after estrogen therapy is discontinued.
Breast cancer
The most important randomized clinical trial providing
information about breast cancer in estrogen-alone users is the WHI substudy of
daily CE (0.625 mg)-alone. In the WHI estrogen-alone substudy, after an average
follow-up of 7.1 years, daily CE (0.625 mg)-alone was not associated with an
increased risk of invasive breast cancer (relative risk [RR] 0.80). (See Clinical
Studies.)
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, respectively. 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 increased 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, doses, or routes of administration.
The use of estrogen-alone and 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.
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 versus placebo 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 an 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-alone ancillary study of WHI, a
population of 2,947 hysterectomized women 65 to 79 years of age was randomized
to daily CE (0.625 mg)-alone or placebo.
After an average follow-up of 5.2 years, 28 women in the
estrogen-alone group and 19 women in the placebo group were diagnosed with
probable dementia. The relative risk of probable dementia for CE-alone versus
placebo was 1.49 (95 percent CI, 0.83-2.66). The absolute risk of probable
dementia for CE-alone versus placebo was 37 versus 25 cases per 10,000
women-years. (See Clinical Studies and PRECAUTIONS, Geriatric
Use.)
In the WHIMS estrogen plus progestin ancillary study of WHI,
a population of 4,532 postmenopausal women 65 to 79 years of age 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. (See Clinical
Studies and PRECAUTIONS, Geriatric Use.)
When data from the two populations in the WHIMS
estrogen-alone and estrogen plus progestin ancillary studies were pooled as
planned in the WHIMS protocol, the reported overall relative risk for probable
dementia was 1.76 (95 percent CI, 1.19-2.60). Since both substudies were
conducted in women 65 to 79 years of age, it is unknown whether these findings
apply to younger postmenopausal women. (See PRECAUTIONS, Geriatric
Use.)
Gallbladder Disease
A 2- to 4-fold increase in the risk of gallbladder disease
requiring surgery in postmenopausal women receiving postmenopausal 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.
Anaphylactic Reaction and Angioedema
Cases of anaphylaxis, which developed within minutes to
hours after using PREMARIN Intravenous and require emergency medical
management, have been reported in the postmarketing setting. Skin (hives,
pruritis, swollen lips-tongue-face) and either respiratory tract (respiratory
compromise) or gastrointestinal tract (abdominal pain, vomiting) involvement
has been noted.
Angioedema involving the tongue, larynx, face, hands, and
feet requiring medical intervention has occurred postmarketing in patients
using PREMARIN Intravenous. If angioedema involves the tongue, glottis, or
larynx, airway obstruction may occur. Patients who develop an anaphylactic
reaction with or without angioedema after treatment with PREMARIN Intravenous
should not receive PREMARIN Intravenous again.
Hereditary Angioedema
Exogenous estrogens may induce or exacerbate symptoms of
angioedema, particularly in women with hereditary angioedema.