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Label Changes for:

Premarin Intravenous (conjugated estrogens, USP) for injection

February 2008

Changes have been made to the WARNINGS, PRECAUTIONS, ADVERSE REACTIONS and PATIENT PACKAGE INSERT sections of the safety label.

Detailed View: Safety Labeling Changes Approved By FDA Center for Drug Evaluation and Research (CDER) -- February 2008


The detailed view includes drug products with safety labeling changes to the BOXED WARNING, CONTRAINDICATIONS, WARNINGS, PRECAUTIONS, ADVERSE REACTIONS, or PATIENT PACKAGE INSERT/MEDICATION GUIDE sections. Deletions or editorial revisions made to these sections are not included in this summary.

Summary View


Sections Modified Summary of Changes to Contraindications and Warnings


  • Malignant Neoplasms
    • Endometrial Cancer
    • Breast Cancer


  • General
  • Ovarian Cancer
    • The estrogen plus progestin substudy of WHI reported a non-statistically significant increased risk of ovarian cancer. After an average follow-up of 5.6 years, the relative risk for ovarian cancer for CE/MPA versus placebo was 1.58 (95 percent nCI 0.77-3.24)...


  • Gastrointestinal
    • Ischemic Colitis
  • Central Nervous System
    • Possible growth potentiation of benign meningioma


  • What can I do to lower my chances of getting a serious side effect with Premarin Intravenous?
    • If you have a uterus, talk with your healthcare provider about whether the addition of a progestin...


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...

Breast Cancer

...The results from observational studies are generally consistent with those of 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...