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Generic Name:

conjugated-estrogens, Oral tablet

All Brands

  • Premarin
SECTION 1 of 4

Highlights for conjugated-estrogens

Oral tablet
1

Conjugated estrogens is a drug that provides estrogen if your body doesn’t make enough estrogen. Conjugated estrogens is used to treat symptoms of menopause and to help reduce the risk of thin, weak bones (osteoporosis). You may also receive estrogen if your ovaries have been removed or don’t make enough estrogen naturally. Conjugated estrogens can also ease the symptoms of prostate and breast cancers in men and women.

2

Your dose depends on the condition that’s being treated. Your doctor will decide a dose that’s right for you.

3

Conjugated estrogens comes in many forms, including: oral tablet, topical and vaginal cream, and an injection, which is given by a healthcare provider.

4

Common side effects include headaches, breast pain, irregular vaginal bleeding, stomach pain, nausea, vomiting, swelling of your arms and legs, and vaginal yeast infections.

5

Tell your doctor right away if you have any new breast lumps, unusual vaginal bleeding, changes in vision and speech, sudden new severe headaches, severe pain in your chest or legs, weakness, or swollen lips, tongue, or face.

IMPORTANT INFORMATION

FDA warning

This drug has a Black Box Warning. This is the most serious warning from the Food & Drug Administration (FDA). Though the medication can still be sold and used, a black box warning alerts doctors and patients to potentially dangerous effects.

Uterine cancer warning. Using estrogen alone may increase your chance of endometrial or uterine cancer. Tell your doctor right away if you have any unusual vaginal bleeding. Vaginal bleeding after menopause may be a sign of endometrial or uterine cancer.

Stroke, blood clot, and dementia warning. Using estrogen alone may increase the chance of having a stroke or blood clot, or dementia in senior women. Using estrogen with progestin may increase your risk of a heart attack, stroke, breast cancer, blood clots, or dementia.

Risk for other conditions

Tell your doctor about all of your medical problems. This drug may make certain conditions worse. These include asthma, seizures, diabetes, migraines, endometriosis, lupus, high calcium levels, or problems with your heart, liver, or kidneys. Check with your doctor to find out if this drug is right for you.

Blood clots

Tell your doctor if you plan to have surgery or will be on bed rest. This drug may cause blood clots. You may need to temporarily stop taking this drug before surgery.

What are conjugated estrogens?

This drug is a prescription drug. It is only available as a brand drug. It’s available in these forms: oral tablet, topical and vaginal cream, and an injection, which is given by a healthcare provider.

If you’re a woman who has gone through menopause (postmenopausal) and has a uterus, progestin should be given along with the conjugated estrogens. This is done to lower your risk of endometrial cancer. If you don’t have a uterus, you don’t usually need combination therapy with progestin. If you’ve had a hysterectomy and have a history of endometriosis, you may need to take progestin.

Why it's used

This drug is used to replace the estrogen the body makes.

More Details

How it works

This drug belongs to a class of drugs called estrogen replacement therapy.

More Details

Why it's used

This drug is used to replace the estrogen the body makes.

Estrogen is produced in women by their ovaries. After menopause, women no longer make estrogen from the ovaries. This drug is given after menopause to reduce hot flashes, treat menopausal changes in and around the vagina, and help reduce the chance of thin, weak bones (osteoporosis).

You may need to take estrogen if your ovaries have been removed or they aren’t working to make enough estrogen. This drug can also ease the symptoms of prostate and breast cancers in men and women.

How it works

This drug belongs to a class of drugs called estrogen replacement therapy. A class of drugs refers to medications that work similarly. They have a similar chemical structure and are often used to treat similar conditions. This drug is a mixture of natural estrogens (conjugated estrogens).

Estrogen is a hormone that’s made by a woman’s ovaries. After menopause, your ovaries don’t make enough estrogen. This can cause symptoms of menopause, such as hot flashes, sweating, and chills. This drug gives your body more estrogen. This treats the symptoms of menopause and osteoporosis that are caused by not having enough estrogen.

In your body, estrogen helps develop and maintain the female reproductive system and sexual characteristics. Estrogen works on the pituitary’s secretion of hormones called gonadotropins (luteinizing hormone and follicle-stimulating hormone).

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SECTION 2 of 4

conjugated-estrogens Side Effects

Oral tablet

Most Common Side Effects

The most common side effects that occur with conjugated estrogens include:

  • headaches

  • breast or back pain

  • irregular vaginal bleeding or spotting

  • upset stomach

  • stomach cramps

  • nausea and vomiting

  • hair loss

  • fluid retention, including swelling of your arms and legs

  • vaginal inflammation or discharge

  • weakness

  • gas

  • trouble sleeping

  • increased tissue growth in your uterus (endometrial hyperplasia). Symptoms may include:

    • unusual bleeding or unusual absence of menstruation
    • pain during intercourse

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

If you experience any of these serious side effects, call your doctor right away. If your symptoms are potentially life threatening, or if you think you’re experiencing a medical emergency, call 9-1-1.

  • heart attack. Symptoms may include:

    • chest pain
  • stroke. Symptoms may include:

    • loss of balance or function on one side of your body
    • slurred speech
  • blood clot. Symptoms may include:

    • shortness of breath
    • sharp chest pain
    • coughing up blood
    • swelling of your arms or legs
    • changes in vision and speech
  • dementia

  • breast cancer. Symptoms may include:

    • new breast lumps
  • womb (uterine or endometrial) cancer. Symptoms may include:

    • unusual vaginal bleeding or spotting
  • ovarian cancer. Your risk may be higher if you take this drug for 5 or more years. Symptoms may include:

    • pelvic or stomach pain
    • bloating
    • feeling full
  • high blood pressure

  • high blood sugar. Symptoms may include:

    • frequent urination
    • thirst
  • gallbladder disease. Symptoms may include:

    • severe stomach pain
    • chest pain
    • heartburn
    • nausea and vomiting
    • fever, chills
    • tender abdomen
  • liver problems. Symptoms may include:

    • yellowing of your skin or whites of your eyes
    • pain in your right upper stomach area
  • enlargement of benign tumors of the uterus (fibroids). Symptoms may include:

    • heavy vaginal bleeding
    • frequent urination
    • painful sex
    • low back pain
  • allergic reaction. Symptoms may include:

    • skin rash
    • shortness of breath
    • sudden new severe headaches
    • severe pains in your chest or legs with or without shortness of breath, weakness, and fatigue
    • swollen lips, tongue, and face
  • high calcium blood levels

  • high triglyceride levels

Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

This drug doesn’t cause drowsiness.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
SECTION 3 of 4

conjugated-estrogens May Interact with Other Medications

Oral tablet

Conjugated estrogens can interact with other medications, herbs, or vitamins you might be taking. That’s why your doctor should manage all of your medications carefully. If you’re curious about how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Note: You can reduce your chances of drug interactions by having all of your prescriptions filled at the same pharmacy. That way, a pharmacist can check for possible drug interactions.

Food interactions

Don’t eat grapefruit or drink grapefruit juice if you’re taking conjugated estrogens. These may increase the levels of conjugated estrogens in your body. This can cause more side effects.

Medications that might interact with this drug

Drugs for seizures
  • phenobarbital
  • carbamazepine

These drugs may decrease the levels of conjugated estrogens in your body. This means that it won’t work as well to treat your condition.

Tuberculosis drug
  • rifampin

This drug may decrease the levels of conjugated estrogens in your body. This means that it won’t work as well to treat your condition.

Herbal product use for depression
  • St John’s wort

This drug may decrease the levels of conjugated estrogens in your body. This means that it won’t work as well to treat your condition.

Drugs for infections
  • erythromycin
  • clarithromycin
  • ketoconazole
  • itraconazole

These drugs may increase the level of conjugated estrogens in your body. This means that you may have more side effects.

Drugs for Human immunodeficiency virus (HIV)
  • ritonavir

This drug may increase the level of conjugated estrogens in your body. This means that you may have more side effects.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Drug warnings
vaginal bleeding
People with vaginal bleeding

If you have vaginal bleeding, conjugated estrogens may make this worse. Vaginal bleeding after menopause may be a sign of uterine or endometrial cancer.

cancer
People with a history of certain cancers

This drug may increase the chance of breast, uterine, or endometrial cancers. It may make cancer that’s estrogen-receptor positive worse.

stroke or heart attack
People with a history of stroke or heart attack

This drug can increase your chance of having another stroke or heart attack.

history of blood clots
People with a history of blood clots

This drug may increase your risk for more blood clots. You shouldn’t take this drug if you’ve had a blood clot in your legs (deep vein thrombosis) or in your lung (pulmonary embolism). You also shouldn’t use this drug if you have a higher risk for blood blots due to a deficiency of protein C, protein S, or antithrombin.

liver problems
People with liver problems

This drug is cleared from your body by your liver. If your liver isn’t working well, this drug may build up in your body and cause more side effects. Use this drug with caution if you had cholestatic jaundice with past estrogen therapy or during pregnancy. If you get this condition again, you should stop taking this drug.

bleeding disorder
People with a bleeding disorder

This drug may increase your risk of bleeding.

gallbladder
People with gallbladder disease

Estrogen increases the risk of gallstones and can make gallbladder disease worse.

high levels of calcium
People with high blood levels of calcium

Estrogen can increase calcium levels in your body. You shouldn’t use this drug if you have hypercalcemia.

high triglyceride levels
People with high triglyceride levels

This may lead to sudden swelling of the pancreas (pancreatitis) if you already have high triglyceride levels. You may need to stop taking this drug.

hypothyroidism
People with hypothyroidism

If you’re taking thyroid replacement therapy, your doctor should check your thyroid function during treatment with this drug. You may need a higher dose of your thyroid medications.

heart failure or kidney problems
People with heart failure or kidney problems

Your doctor should monitor you during treatment if you have heart failure or kidney problems that can get worse from increased fluid in the body. Estrogen increases fluid in the body (fluid retention).

hyperparathyroidism
People with hypoparathyroidism

This drug can cause low calcium levels if your parathyroid doesn’t work well. 

hereditary angioedema
People with hereditary angioedema

This drug can make symptoms of hereditary angioedema worse.

endometriosis
People with endometriosis

If you have endometriosis after having a hysterectomy and are treated with this drug alone, your risk of endometrial cancer may be higher. Your doctor may also prescribe progestin to lower your risk.

asthma
People with asthma

This drug can increase fluid retention, which can make this condition worse.

diabetes
People with diabetes

This drug can decrease insulin sensitivity, which can worsen blood sugar levels.

seizures
People with seizures

This drug can increase fluid retention, which can make this condition worse.

headaches
People with headaches

This drug can increase fluid retention, which can make this condition worse.

porphyria
People with porphyria

This drug can make this condition worse.

lupus
People with lupus

This drug can increase the risk of clot formation. Patients with lupus also have an increased risk of clot formation. Together they both increase clot risk.

liver hemangiomas
People with liver hemangiomas

This drug can make the tumor grow larger and make this condition worse.

pregnant women
Pregnant women

This drug is a category X pregnancy drug. Category X drugs should never be used during pregnancy.

Tell your doctor if you’re pregnant or plan to become pregnant.

breastfeeding
Women who are breast-feeding

This drug changes breast milk. It lowers the amount and quality of breast milk. It also passes into breast milk and can cause serious effects in a breastfeeding child.

You and your doctor may need to decide if you’ll breastfeed or take this drug.

for seniors
For seniors

This drug used alone or with progestin may increase the risk of stroke, invasive breast cancer, and dementia in seniors.

call doctor
When to call the doctor

Tell your doctor if you’re going to have surgery. You may need to stop taking this drug for a short time.

allergies
Allergies

This drug can cause a severe allergic reaction. Symptoms may include:

  • swelling of your face and tongue (angioedema)
  • trouble breathing
  • stomach pain
  • vomiting

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal.

SECTION 4 of 4

How to Take conjugated-estrogens (Dosage)

Oral tablet

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

Moderate to severe symptoms of menopause

Brand: Premarin

Form: Oral tablet
Strengths: 0.3 mg, 0.45 mg, 0.625 mg, 0.9 mg, 1.25 mg
Adult dosage (ages 18 years and older)
  • All tablet strengths can be taken once daily. For cyclical administration (taking for 25 days and then not taking it for 5 days), usually the 0.3-mg, 0.625-mg, and 1.25-mg tablets are used.
  • The starting dose is one 0.3-mg tablet taken by mouth once a day.
  • Your doctor may increase your dose if needed to control symptoms.
  • This drug is given either daily or as a cycle. In a cycle, you take the drug for 25 days, and then you stop taking the drug for 5 days.  
Child dosage (ages 0-17 years)

Dosage for children younger than 18 years of age hasn’t been established.

Warnings

You should use the lowest effective dose for the shortest amount of time it takes to achieve your treatment goals. This is done to decrease your risk of side effects. You and your doctor should talk from time to time during your treatment to decide if you still need estrogen.

Vulvar and vaginal atrophy of menopause

Brand: Premarin

Form: Oral tablet
Strengths: 0.3 mg, 0.45 mg, 0.625 mg, 0.9 mg, 1.25 mg
Adult dosage (ages 18 years and older)
  • All tablet strengths can be taken once daily. For cyclical administration (taking for 25 days and then not taking it for 5 days), usually the 0.3-mg, 0.625-mg, and 1.25-mg tablets are used.
  • The starting dose is one 0.3-mg tablet taken by mouth once a day.
  • Your doctor may increase your dose if needed to control symptoms.
  • This drug is given either daily or as a cycle. In a cycle, you take the drug for 25 days, and then you stop taking the drug for 5 days. 
Child dosage (ages 0-17 years)

Dosage for children younger than 18 years of age hasn’t been established.

Warnings

You should use the lowest effective dose for the shortest amount of time it takes to achieve your treatment goals. This is done to decrease your risk of side effects. You and your doctor should talk from time to time during your treatment to decide if you still need estrogen.

Low estrogen levels

Brand: Premarin

Form: Oral tablet
Strengths: 0.3 mg, 0.45 mg, 0.625 mg, 0.9 mg, 1.25 mg
Adult dosage (ages 18 years and older)
  • All tablet strengths can be taken once daily. For cyclical administration (taking for 25 days and then not taking it for 5 days), usually the 0.3-mg, 0.625-mg, and 1.25-mg tablets are used.
  • Female hypogonadism: The dose is 0.3–0.625 mg taken by mouth once per day. You’ll take it for three weeks, and then you’ll stop taking the drug for one week (cyclical therapy).
  • Female castration and primary ovarian failure: The dose is 1.25 mg taken by mouth once a day. You’ll take it for three weeks and then you’ll stop taking the drug for one week (cyclical therapy).
  • Your doctor may increase or decrease your dose depending on your symptoms and how you respond to treatment. Your maintenance dose should be the lowest dose that controls your symptoms.
Child dosage (ages 0-17 years)

Dosage for children younger than 18 years of age hasn’t been established.

Warnings

You should use the lowest effective dose for the shortest amount of time it takes to achieve your treatment goals. This is done to decrease your risk of side effects. You and your doctor should talk from time to time during your treatment to decide if you still need estrogen.

Metastatic breast cancer

Brand: Premarin

Form: Oral tablet
Strengths: 0.3 mg, 0.45 mg, 0.625 mg, 0.9 mg, 1.25 mg
Adult dosage (ages 18 years and older)
  • All tablet strengths can be taken once daily. For cyclical administration (taking for 25 days and then not taking it for 5 days), usually the 0.3-mg, 0.625-mg, and 1.25-mg tablets are used. 
  • The dose is 10 mg (eight 1.25-mg tablets) taken by mouth 3 times per day for at least three months.
Child dosage (ages 0-17 years)

Dosage for children younger than 18 years of age hasn’t been established.

Warnings

You should use the lowest effective dose for the shortest amount of time it takes to achieve your treatment goals. This is done to decrease your risk of side effects. You and your doctor should talk from time to time during your treatment to decide if you still need estrogen.

Prostate cancer

Brand: Premarin

Form: Oral tablet
Strengths: 0.3 mg, 0.45 mg, 0.625 mg, 0.9 mg, 1.25 mg
Adult dosage (ages 18 years and older)
  • All tablet strengths can be taken once daily. For cyclical administration (taking for 25 days and then not taking it for 5 days), usually the 0.3-mg, 0.625-mg, and 1.25-mg tablets are used.
  • The dose is 1–2 1.25- mg tablets taken by mouth 3 times per day.
Child dosage (ages 0-17 years)

Dosage for children younger than 18 years of age hasn’t been established.

Warnings

You should use the lowest effective dose for the shortest amount of time it takes to achieve your treatment goals. This is done to decrease your risk of side effects. You and your doctor should talk from time to time during your treatment to decide if you still need estrogen.

Prevention of postmenopausal osteoporosis

Brand: Premarin

Form: Oral tablet
Strengths: 0.3 mg, 0.45 mg, 0.625 mg, 0.9 mg, 1.25 mg
Adult dosage (ages 18 years and older)
  • All tablet strengths can be taken once daily. For cyclical administration (taking for 25 days and then not taking it for 5 days), usually the 0.3-mg, 0.625-mg, and 1.25-mg tablets are used.
  • The starting dose is 0.3 mg taken by mouth once per day.
  • You may take this drug daily or in cycles. In a cycle, you take the drug for 25 days, and then you stop taking the drug for 5 days.
  • Your doctor may increase your dose based on your response to the drug and your bone mineral density results.
Child dosage (ages 0-17 years)

Dosage for children younger than 18 years of age hasn’t been established.

 Warnings

You should use the lowest effective dose for the shortest amount of time it takes to achieve your treatment goals. This is done to decrease your risk of side effects. You and your doctor should talk from time to time during your treatment to decide if you still need estrogen.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

This drug comes with serious risks if you don’t take it exactly as prescribed.

If you don't take it at all or if you stop taking it suddenly

Your symptoms of menopause, such as hot flashes, sweating, and chills, or the other condition that you’re treating may not get better.

If you take too much

If you take too much conjugated estrogens, you may have the following symptoms:

  • nausea
  • tender breasts
  • stomach pain
  • tiredness
  • vaginal bleeding in women

Call your doctor if you think that you’ve taken too much of this drug. Your doctor may treat your symptoms and may have you temporarily stop taking conjugated estrogens.

What to do if you miss a dose

If you forget to take your dose, take it as soon as you remember. If it’s just a few hours before the time for your next dose, then wait and only take one dose at that time.

Never try to catch up by taking two doses at once. This could result in toxic side effects.

How to tell if the drug is working

If you’re taking this drug to treat moderate to severe symptoms of menopause, your symptoms of menopause such as hot flashes, sweating, and chills may get better.

If you’re taking this drug to treat moderate to severe symptoms of vulvar and vaginal atrophy due to menopause, your symptoms of vaginal or vulvar atrophy such as vaginal dryness, itching, and soreness may get better.

If you’re taking this drug to treat low estrogen due to hypogonadism, castration, or primary ovarian failure, your symptoms such as hot flashes, loss of body hair, and low sex drive may get better.

If you’re taking this drug to ease the symptoms of breast cancer, your symptoms of breast cancer may get better.

If you’re taking this drug to ease the symptoms of prostate cancer, your symptoms of prostate cancer may get better. Your doctor may also check your phosphatase levels to tell if the drug is working.

If you’re taking this drug to prevent postmenopausal osteoporosis, you may be able to tell if this drug is working if your bone strength doesn’t decrease. Your doctor may also do bone density tests to tell if the drug is working.

This drug is a short-term or long-term drug.

This depends on the condition that’s being treated and how your body responds to the drug.

Important considerations for taking this drug
timing
Take this medication at the same time every day
can crush or cut
You can cut or crush the oral tablets
storage
Store this drug at room temperature
See Details
prescription is refillable
Prescription is refillable
travel
Travel
See Details
clinical monitoring
Clinical monitoring
See Details

Store this drug at room temperature

Keep it from 68–77°F (20–25°C).

Don’t freeze this drug.

Keep this drug away from high temperature.

Keep your drugs away from areas where they could get wet, such as bathrooms. Store this drug away from moisture and damp locations.

Travel

Always carry your medication with you. Don’t worry about airport x-ray machines. They can’t hurt this medication. You may need to show your pharmacy’s label to clearly identify the medication. Keep the original prescription label with you when traveling.

Clinical monitoring

Your doctor may monitor you with tests. Your doctor may do tests before you begin and during treatment with this drug to make sure it’s safe for you to take:

  • blood pressure
  • body weight
  • gallbladder function
  • heart function
  • thyroid function
  • kidney function
  • liver function
  • laboratory blood tests to check follicle stimulating hormone, estradiol, cholesterol, calcium, and blood sugar levels

Your doctor will also check you for side effects, such as:

  • vaginal bleeding
  • changes in your breasts or uterus
  • blood clots
  • vision changes

You should also:

  • have a pelvic exam, breast exam, and breast x-ray (mammogram) every year. If you have a family history of breast cancer or have a history of breast lumps or abnormal mammograms, you may need to get a breast x-ray more often.
  • do breast self-exams as your doctor has taught you. This will help you check for breast lumps that could be cancerous. 

If you’re taking this drug to ease the symptoms of prostate cancer, your doctor will check your phosphatase levels and symptoms.

If you’re taking this drug to prevent postmenopausal osteoporosis, your doctor will check your bone density.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.


Show Sources

Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on August 11, 2015

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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