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Premarin (Intravenous)


Generic Name: conjugated estrogens (Intravenous route)

KON-joo-gay-ted ES-troe-jenz

Intravenous route(Powder for Solution)

Estrogens increase the risk of endometrial cancer; monitor for abnormal vaginal bleeding. Estrogens with or without progestins should not be used for the prevention of cardiovascular disease or dementia. Increased risks of myocardial infarction, stroke, invasive breast cancer, pulmonary emboli, and DVT in postmenopausal women (50 to 79 years of age) have been reported. An increased risk of developing probable dementia in postmenopausal women 65 years of age or older has also been reported .

Commonly used brand name(s)

In the U.S.

  • Premarin

Available Dosage Forms:

  • Powder for Solution

Therapeutic Class: Endocrine-Metabolic Agent

Pharmacologic Class: Estrogen

Uses For Premarin

Conjugated estrogens is a medicine that contains a mixture of estrogen hormones. Conjugated estrogens injection is used to treat abnormal bleeding from your uterus caused by hormonal imbalance when your doctor has found no other cause of bleeding. This medicine is to be given for short-term use only, to provide a fast and temporary increase in your estrogen levels.

This medicine is to be given only by or under the direct supervision of a doctor.

Before Using Premarin

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies have not been performed on the relationship of age to the effects of Premarin® injection in the pediatric population. Safety and efficacy have not been established.


Although appropriate studies on the relationship of age to the effects of Premarin® injection have not been performed in the geriatric population, no geriatric-specific problems have been documented to date. However, elderly patients are more likely to have breast cancer, stroke, or dementia, which may require caution in patients receiving this medicine.


Pregnancy Category Explanation
All Trimesters X Studies in animals or pregnant women have demonstrated positive evidence of fetal abnormalities. This drug should not be used in women who are or may become pregnant because the risk clearly outweighs any possible benefit.

Breast Feeding

Studies suggest that this medication may alter milk production or composition. If an alternative to this medication is not prescribed, you should monitor the infant for side effects and adequate milk intake.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Bupropion
  • Dasabuvir
  • Donepezil
  • Paritaprevir

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Clarithromycin
  • Etoricoxib
  • Ginseng
  • Itraconazole
  • Ketoconazole
  • Levothyroxine
  • Licorice
  • St John's Wort
  • Tipranavir

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

  • Grapefruit Juice

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Blood clots (e.g., deep vein thrombosis, pulmonary embolism), active or history of or
  • Breast cancer, known or suspected, or a history of or
  • Heart attack, history of or
  • Liver disease or
  • Protein C, protein S, or other known blood clotting disorders or
  • Stroke, history of or
  • Tumors (estrogen-dependent), known or suspected—Should not be used in patients with these conditions.
  • Asthma or
  • Cancer, history of or
  • Diabetes or
  • Edema (fluid retention or body swelling) or
  • Endometriosis or
  • Epilepsy (seizures) or
  • Gallbladder disease or
  • Heart disease or
  • Hereditary angioedema (swelling of the face, lips, tongue, or throat) or
  • Hypercalcemia (high calcium in the blood) or
  • Hypertension (high blood pressure) or
  • Hypertriglyceridemia (high triglycerides or fats in the blood) or
  • Hypocalcemia (low calcium in the blood) or
  • Hypothyroidism (an underactive thyroid) or
  • Jaundice during pregnancy or from using hormonal therapy in the past or
  • Liver tumors or
  • Migraine headache or
  • Porphyria (an enzyme problem) or
  • Systemic lupus erythematosus (SLE)—Use with caution. May make these conditions worse.

Proper Use of Premarin

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. This medicine is not for long-term use.

This medicine comes with a patient information leaflet. Read the information carefully. Ask your doctor if you have any questions.

Precautions While Using Premarin

It is very important that your doctor check you closely to make sure this medicine is working properly and does not cause unwanted effects. Pelvic exam, breast exam, and mammogram (breast x-ray) may be needed to check for unwanted effects, unless your doctor tells you otherwise.

Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away.

Using this medicine may increase your risk of endometrial cancer, breast cancer, or uterine cancer. Talk with your doctor about this risk. If you still have your uterus (womb), ask your doctor if you should also use a progestin medicine. Check with your doctor immediately if your experience abnormal vaginal bleeding.

Using this medicine may increase your risk of dementia, especially in women 65 years of age and older.

Using this medicine may increase your risk for having blood clots, strokes, or heart attacks. This risk may continue even after you stop using the medicine. Your risk for these serious problems is even greater if you have high blood pressure, high cholesterol in your blood, diabetes, or are overweight or smoke cigarettes. Contact your doctor immediately if you experience confusion, difficulty speaking, double vision, headaches, an inability to move arms, legs or facial muscle, or an inability to speak.

This medicine may cause serious types of allergic reactions, including anaphylaxis and angioedema. Anaphylaxis and angioedema can be life-threatening and require immediate medical attention. Call your doctor right away if you have a rash; itching; hoarseness; trouble breathing; trouble swallowing; or any swelling of your hands, face, mouth, or throat while you are using this medicine.

Pancreatitis may occur while you are using this medicine. Check with your doctor right away if you have sudden and severe stomach pain, chills, constipation, nausea, vomiting, fever, or lightheadedness.

Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this medicine before you have surgery or if you need to stay in bed for an extended time. This medicine may affect the results of certain medical tests.

Check with your doctor immediately if severe headache or sudden loss of vision or any other change in vision occurs while you are using this medicine. Your doctor may want you to have your eyes checked by an ophthalmologist (eye doctor).

Do not eat grapefruit or drink grapefruit juice while you are using this medicine. Grapefruit and grapefruit juice may change the amount of this medicine that is absorbed in the body.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (e.g., St. John's wort) or vitamin supplements.

Premarin Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

Incidence not known
  • Abdominal or stomach cramps, pain, or tenderness
  • anxiety
  • backache
  • blistering, peeling, or loosening of the skin
  • bloody or clay-colored stools
  • changes in skin color
  • chest pain or discomfort
  • chills or fever
  • clear or bloody discharge from the nipple
  • cough or sore throat
  • darkened urine
  • difficulty with speaking
  • dizziness, lightheadedness, or confusion
  • double vision
  • fainting
  • fast heartbeat
  • fluid-filled skin blisters
  • headache, severe and throbbing
  • heartburn or indigestion
  • heavy bleeding
  • inability to move the arms, legs, or facial muscles
  • irregular heartbeats
  • joint or muscle pain
  • loss of appetite
  • loss of bladder control
  • lump in the breast or under the arm
  • muscle cramps in the hands, arms, feet, legs, or face
  • muscle spasm or jerking of all extremities
  • nausea, vomiting, or diarrhea
  • numbness and tingling around the mouth, fingertips, or feet
  • pain or discomfort in the arms, jaw, back, or neck
  • pain, redness, or swelling in the arm or leg
  • painful or tender cysts in the breasts
  • painful, red lumps under the skin, mostly on the legs
  • rash, hives or welts
  • rectal bleeding
  • red, irritated eyes
  • redness or swelling of the breast
  • sensitivity to the sun
  • sore on the skin of the breast that does not heal
  • sores, ulcers, or white spots in the mouth or on the lips
  • stomach discomfort or upset
  • sudden loss of consciousness
  • sudden shortness of breath or troubled breathing
  • sweating
  • swelling of the foot or leg
  • tremor
  • unusual tiredness or weakness
  • vomiting of blood
  • yellow eyes or skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known
  • Brown, blotchy spots on exposed skin
  • decreased interest in sexual intercourse
  • difficulty of wearing contact lenses
  • hair loss in the scalp
  • increase or decrease in weight
  • increased hair growth, especially on the face
  • mental depression
  • muscle pain or stiffness
  • pain or swelling at the injection site
  • twitching, uncontrolled movements of the tongue, lips, face, arms, or legs

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

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

See also: Side effects (in more detail)

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