Precautions and Warnings With Esterified Estrogens

Specific Warnings and Precautions for Esterified Estrogens

Some of the warnings and precautions to be aware of prior to using esterified estrogens include the following:
  • For women who still have a uterus (who have not had a hysterectomy), taking esterified estrogens alone (without a progestin) increases the risk of endometrial cancer (cancer of the lining of the uterus). Women who still have a uterus should take esterified estrogens with a progestin medication.
  • Your healthcare provider should make sure that you are appropriately treated for any risk factors for heart disease (such as high blood pressure, high cholesterol, diabetes, obesity, or smoking) or blood clots before you take esterified estrogens. Studies have shown that estrogen hormone replacement therapy (such as esterified estrogens) increases the risk of strokes and blood clots in the legs.
  • Esterified estrogens should never be used to prevent heart disease (see Hormone Replacement Therapy and Heart Health for more information), as it is not effective for this use.
  • Let your healthcare provider know if you have abnormal vaginal bleeding (such as very heavy bleeding or bleeding between periods) while taking esterified estrogens, as this may be a sign of precancerous or cancerous changes in the uterus. Your healthcare provider can perform the necessary tests to rule out cancer.
  • When possible, esterified estrogens should be stopped four to six weeks before many surgeries, in order to help prevent blood clots.
  • Estrogen drugs (such as esterified estrogens) used with or without a progestin may increase the risk of breast cancer. Proper screening and monitoring (as determined by your healthcare provider), such as yearly mammograms and monthly breast self-exams, is recommended.
  • Estrogen drugs (such as esterified estrogens) used with or without a progestin seem to increase the risk of dementia. In no case should esterified estrogens be used to prevent or treat dementia (it is not effective for this use).
  • Women who take estrogen (such as esterified estrogens) have an increased risk for gallbladder disease.
  • Let your healthcare provider know right away if you notice any vision changes. This can signal a blood clot in the retina, a possible side effect of esterified estrogens.
  • Esterified estrogens can cause high blood pressure (hypertension) or high triglycerides in some women. Your healthcare provider should monitor you for these problems.
  • If you have had jaundice (yellowing of the whites of the eyes or skin) due to estrogens or pregnancy in the past, it is possible that esterified estrogens will cause similar problems to recur. If this happens, your healthcare provider will probably advise you to stop taking esterified estrogens.
  • If you have an underactive thyroid (hypothyroidism), esterified estrogens may increase your body's requirement for thyroid hormones. Your healthcare provider should monitor you and adjust the dose of your thyroid medications as necessary.
  • Esterified estrogens can cause fluid retention. This can cause problems for people with congestive heart failure (CHF) or kidney problems.
  • Esterified estrogens should be used with caution in people who have low calcium levels in the blood (known medically as hypocalcemia).
  • It is not clear whether esterified estrogens increases the risk of ovarian cancer. Some studies have shown an increased risk, while others have not.
  • Esterified estrogens can make endometriosis symptoms worse.
  • Esterified estrogens can interact with a number of different medications (see Drug Interactions With Esterified Estrogens for more information).
  • Esterified estrogens should not be used during pregnancy (see Menest and Pregnancy).
  • Esterified estrogens does pass through breast milk. Therefore, if you are breastfeeding or plan to start breastfeeding, discuss this with your healthcare provider prior to taking the drug (see Menest and Breastfeeding).
Last reviewed by: Kristi Monson, PharmD
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