Premarin precautions
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
List of precautions
Addition of a progestin when a woman has not had a hysterectomy
Elevated blood pressure
Hypertriglyceridemia
Impaired liver function and past history of cholestatic jaundice
Hypothyroidism
Fluid retention
Hypocalcemia
Ovarian cancer
Exacerbation of endometriosis
Addition of a progestin when a woman has not had a hysterectomy
Studies of the addition of a progestin for 10 or more days of a cycle of estrogen administration,
or daily with estrogen in a continuous regimen, have reported a lowered incidence of endometrial
hyperplasia than would be induced by estrogen treatment alone. Endometrial hyperplasia may be
a precursor to endometrial cancer.
There are, however, possible risks that may be associated with the use of progestins with
estrogens compared with estrogen-alone regimens. These include a possible increased risk of
breast cancer, adverse effects on lipoprotein metabolism (e.g., lowering HDL, raising LDL) and
impairment of glucose tolerance. Return to top
Elevated blood pressure
In a small number of case reports, substantial increases in blood pressure have been attributed to
idiosyncratic reactions to estrogens. In a large, randomized, placebo-controlled clinical trial, a
generalized effect of estrogen therapy on blood pressure was not seen. Blood pressure should be
monitored at regular intervals with estrogen use. Return to top
Hypertriglyceridemia
In patients with pre-existing hypertriglyceridemia, estrogen therapy may be associated with
elevations of plasma triglycerides leading to pancreatitis and other complications. In the HOPE
study, the mean percent increase from baseline in serum triglycerides after one year of treatment
with Premarin 0.625 mg/2.5 mg, 0.45 mg/1.5 mg, and 0.3 mg/1.5 mg compared with placebo
were 32.8, 24.8, 23.3, and 10.7, respectively. After two years of treatment, the mean percent
changes were 33.0, 17.1, 21.6, and 5.5, respectively. Return to top
Impaired liver function and past history of cholestatic jaundice
Estrogens may be poorly metabolized in patients with impaired liver function. For patients with a
history of cholestatic jaundice associated with past estrogen use or with pregnancy, caution
should be exercised and in the case of recurrence, medication should be discontinued. Return to top
Hypothyroidism
Estrogen administration leads to increased thyroid-binding globulin (TBG) levels. Patients with
normal thyroid function can compensate for the increased TBG by making more thyroid
hormone, thus maintaining free T4 and T3 serum concentrations in the normal range. Patients
dependent on thyroid hormone replacement therapy who are also receiving estrogens may
require increased doses of their thyroid replacement therapy. These patients should have their
thyroid function monitored in order to maintain their free thyroid hormone levels in an
acceptable range. Return to top
Fluid retention
Because estrogens/progestins may cause some degree of fluid retention, patients with conditions
that might be influenced by this factor, such as cardiac or renal dysfunction, warrant careful
observation when estrogens are prescribed. Return to top
Hypocalcemia
Estrogens should be used with caution in individuals with severe hypocalcemia Return to top
Ovarian cancer
Use of estrogen-only products, in particular for ten or more years, has been associated with an
increased risk of ovarian cancer in some epidemiological studies. Other studies did not show a
significant association. Data are insufficient to determine whether there is an increased risk with
combined estrogen/progestin therapy in postmenopausal women. Return to top
Exacerbation of endometriosis
Endometriosis may be exacerbated with administration of estrogens. Return to top
Exacerbation of other conditions
Estrogens may cause an exacerbation of asthma, diabetes mellitus, epilepsy, migraine, porphyria,
systemic lupus erythematosus, and hepatic hemangiomas and should be used with caution in
women with these conditions. Return to top
Adapted from the FDA Package Insert.