Health Guide

Conjugated estrogens (By injection)

Conjugated Estrogens (KON-joo-gay-ted ES-troe-jenz)

Treats abnormal bleeding from your uterus caused by a hormonal imbalance.

Brand Name(s):

Premarin Intravenous

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use it if you had angioedema or an allergic reaction to conjugated estrogens, or if you are pregnant or have unusual vaginal bleeding not checked by a doctor. Do not use it if you have liver disease, breast cancer, blood clotting problems, or a history of blood clots, heart attack, or stroke.

How to Use This Medicine:


  • A nurse or other trained health professional will give you this medicine in a hospital. This medicine is given into a vein or into a muscle.
  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
  • This medicine is not for long-term use.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Some medicines and foods can affect how this medicine works. Tell your doctor if you are taking any of the following:
    • Carbamazepine, phenobarbital
    • Clarithromycin, erythromycin
    • Itraconazole, ketoconazole
    • Rifampin
    • Ritonavir
    • St John's wort
    • Thyroid medicine
  • Do not eat grapefruit or drink grapefruit juice while you are using this medicine.

Warnings While Using This Medicine:

  • It is not safe to take this medicine during pregnancy. It could harm an unborn baby. Tell your doctor right away if you become pregnant.
  • Tell your doctor if you are breastfeeding or if you have endometriosis, heart disease, high blood pressure, kidney or gallbladder disease, edema, asthma, diabetes, epilepsy, lupus, migraine headaches, porphyria, thyroid problems, liver problems, a history of cancer, or a family history of breast cancer or high cholesterol.
  • This medicine may increase your risk for the following:
    • Certain cancers, such as breast or uterine cancer
    • Heart attack or dementia
    • Stroke or blood clots, especially if you smoke, you have high blood pressure, high cholesterol, or diabetes, or you are overweight
  • Tell your doctor if you have a sudden, severe headache or vision changes while you are taking this medicine. He may want you to have your eyes checked by an eye doctor.
  • Tell any doctor or dentist who treats you that you are using this medicine. This medicine may affect certain medical test results. Tell any doctor or dentist who treats you that you are taking this medicine. You may need to stop taking it before you have surgery or if you need to be on bedrest.
  • Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments. You should have regular pelvic exams, breast exams, and mammograms as directed by your doctor.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Breast lump
  • Chest pain, trouble breathing, coughing up blood
  • Numbness or weakness on one side of your body, sudden or severe headache, problems with vision, speech, or walking
  • Pain in your calf
  • Swelling in your hands, ankles, or feet
  • Sudden and severe stomach pain, nausea, vomiting
  • Unusual or unexpected vaginal bleeding or heavy bleeding
  • Vision changes
  • Yellow skin or eyes

If you notice these less serious side effects, talk with your doctor:

  • Mild nausea, vomiting, stomach cramps
  • Pain, itching, swelling, or a rash where the needle is placed
  • Swollen or tender breasts

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 7/4/2018
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