Generic name: conjugated estrogens [ KON-joo-gay-ted-ES-troe-jenz ]
Drug class: Estrogens
Medically reviewed by Drugs.com. Last updated on Jul 13, 2023.
There is an increased risk of endometrial cancer in a woman with a uterus who uses unopposed estrogens. Adding a progestin to estrogen therapy has been shown to reduce the risk of endometrial hyperplasia, which may be a precursor to endometrial cancer. Adequate diagnostic measures, including directed or random endometrial sampling when indicated, should be undertaken to rule out malignancy in postmenopausal women with undiagnosed persistent or recurring abnormal genital bleeding.
Cardiovascular Disorders and Probable Dementia
Estrogen-alone therapy should not be used for the prevention of cardiovascular disease or dementia.
The Women’s Health Initiative estrogen-alone substudy reported increased risks of stroke and deep vein thrombosis in postmenopausal women (50 to 79 years of age) during 7.1 years of treatment with daily oral conjugated estrogens (0.625 mg)-alone, relative to placebo.
The Women’s Health Initiative Memory Study estrogen-alone ancillary study of the Women’s Health Initiative reported an increased risk of developing probable dementia in postmenopausal women 65 years of age or older during 5.2 years of treatment with daily conjugated estrogens (0.625 mg)-alone, relative to placebo. It is unknown whether this finding applies to younger postmenopausal women.
In the absence of comparable data, these risks should be assumed to be similar for other doses of conjugated estrogens and other dosage forms of estrogens
Estrogens with or without progestins should be prescribed at the lowest effective doses and for the shortest duration consistent with treatment goals and risks for the individual woman.
Estrogen Plus Progestin Therapy
Cardiovascular Disorders and Probable Dementia
Estrogen plus progestin therapy should not be used for the prevention of cardiovascular disease or dementia.
The Women’s Health Initiative estrogen plus progestin substudy reported increased risks of DVT, pulmonary embolism, stroke and myocardial infarction in postmenopausal women (50 to 79 years of age) during 5.6 years of treatment with daily oral conjugated estrogens (0.625 mg) combined with medroxyprogesterone acetate (2.5 mg), relative to placebo.
The Women’s Health Initiative Memory Study estrogen plus progestin ancillary study of the Women’s Health Initiative reported an increased risk of developing probable dementia in postmenopausal women 65 years of age or older during 4 years of treatment with daily conjugated estrogens (0.625 mg) combined with medroxyprogesterone acetate (2.5 mg), relative to placebo. It is unknown whether this finding applies to younger postmenopausal women.
The Women’s Health Initiative estrogen plus progestin substudy also demonstrated an increased risk of invasive breast cancer.
In the absence of comparable data, these risks should be assumed to be similar for other doses of conjugated estrogens and medroxyprogesterone acetate, and other combinations and dosage forms of estrogens and progestins.
Estrogens with or without progestins should be prescribed at the lowest effective doses and for the shortest duration consistent with treatment goals and risks for the individual woman .
Uses for conjugated estrogens
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 conjugated estrogens
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.
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.
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.
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. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
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 conjugated estrogens
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 conjugated estrogens
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.
Side Effects of conjugated estrogens
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
- 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
- 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
- swelling of the foot or leg
- 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.
More about conjugated estrogens
- Check interactions
- Compare alternatives
- Reviews (91)
- Side effects
- Dosage information
- During pregnancy
- Drug class: estrogens
- En español
- Conjugated estrogens drug information
- Conjugated estrogens (Oral) (Advanced Reading)
- Conjugated estrogens synthetic a (Advanced Reading)
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