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Overview: Premarin is taken to replace estrogen hormones in the body to help with symptoms of menopause, prevent osteoporosis after menopause, or raise estrogen levels when the ovaries are not working properly or have been removed. It can also be used to lower androgen (male hormone) levels in certain types of advanced cancers. Common side effects include headache, nausea, and breast tenderness. Before taking Premarin, tell your health care provider about any health conditions or medicines you are taking. Get emergency help if you have trouble breathing, chest pain, vision changes, or trouble speaking.

Uses

What is Premarin used for?

Premarin (conjugated estrogens) is commonly used for the following conditions.

Premarin may also be used for other conditions as determined by your health care provider.

How does Premarin work (mechanism of action)?

Premarin works by replacing estrogen, a hormone your body makes less of during menopause or when the ovaries are not working properly or have been removed. In certain cases of advanced breast or prostate cancer, Premarin can also help lower levels of male hormones (androgens). 

How is Premarin supplied (dosage forms)?

Brands and other names

  • Premarin

Dosage forms and strengths

  • 0.3 mg, 0.45 mg, 0.625 mg, 0.9 mg, 1.25 mg oral tablets

Premarin is also available in a vaginal form that is inserted into the vagina. See Premarin vaginal (conjugated estrogens) for more information.

How should I store Premarin?

Premarin should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place. 

Side Effects

What are the most common side effects of Premarin?

The most common side effects of Premarin are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Stomach pain, cramps, bloating, gas, nausea, or vomiting
  • Feeling unusually weak or tired
  • Headache
  • Back pain
  • Depression
  • Trouble sleeping
  • Breast pain or tenderness
  • Vaginal discharge, inflammation, or yeast infection
  • Irregular vaginal bleeding or spotting
  • Hair loss
  • Fluid retention (see below)

There may be other side effects of Premarin that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of Premarin?

While less common, the most serious side effects of Premarin are described below, along with what to do if they happen.

Severe Allergic Reactions. Premarin may cause allergic reactions, which can be serious. Stop taking Premarin and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Blood Clots. Premarin may cause a blood clot in your arteries or veins and could cause a stroke, heart attack, or venous thromboembolism (VTE), including a blood clot in the lungs (pulmonary embolism), in the back of your eye (retinal vein occlusion), or in your legs or arms (deep venous thrombosis). Stop taking Premarin and get emergency help if you have any of the following signs of a blood clot.

  • Chest pain or pressure
  • Fast or abnormal heartbeat
  • Trouble breathing
  • Pain in your back, jaw, throat, or arm
  • Sweating, upset stomach, vomiting, or dizziness
  • Sudden weakness on one side of your body
  • Sudden and severe headache
  • Slurred speech or trouble understanding speech
  • Pain, swelling, or tenderness in your arm or leg
  • Vision loss
  • Bulging eyes
  • Double vision

Gallbladder Problems. Taking Premarin can cause gallbladder problems, including cholecystitis and cholelithiasis (also known as gallstones). Call your health care provider right away if you have any of the following symptoms.

  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)
  • Fever
  • Pain in your upper stomach area
  • Clay-colored stool (poop)

Endometrial Cancer. You may be at a higher risk for cancer in the lining of your uterus (endometrial cancer) if you take Premarin. Call your health care provider right away if you have any abnormal vaginal bleeding.

Breast Cancer. You may be at a higher risk for breast cancer if you take Premarin. Call your health care provider right away if you have any of the following symptoms.

  • New lump in your breast or armpit
  • Changes in the size, shape, texture, or temperature of your breast
  • Nipple changes

Ovarian Cancer. You may be at a higher risk for cancer in your ovaries (ovarian cancer) if you take Premarin. Call your health care provider right away if you have any of the following symptoms.

  • Unusual vaginal discharge
  • Belly or back pain
  • Need to pee more often or urgently

Dementia. Premarin may increase the risk of slowing of your brain function, especially if you are 65 or older. Tell your health care provider right away if you or your friends or family notice that you have any of the following.

  • Memory problems, such as asking the same question over and over
  • Confusion or disorientation
  • Trouble with complex but familiar tasks, such as cooking a meal or paying your bills
  • Personality changes, such as depression, agitation, paranoia, and mood swings

Increased Blood Sugar. Premarin may increase your blood sugar levels. Talk to your health care provider about how to maintain healthy blood sugar levels.

Increased Blood Pressure (Hypertension). Premarin may increase your blood pressure or make it worse if you have a history of high blood pressure. Call your health care provider if your blood pressure increases while taking this medicine.

Fluid Retention (Edema). Premarin can cause fluid retention, also called edema. Fluid retention can cause serious issues in people with certain conditions, such as heart failure or kidney problems. Call your health care provider right away if you have any of the following symptoms.

  • Chest pain
  • Irregular heartbeat
  • Shortness of breath
  • Stretched or shiny skin
  • Swollen body parts, such as the belly or ankles

Warnings & Precautions

Who should not use Premarin?

Allergies to Ingredients. People who are allergic to any of the following should not take Premarin.

  • Conjugated estrogens
  • Premarin
  • Any other medicine known as an estrogen
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in Premarin.

Unusual Vaginal Bleeding. Premarin should not be used if you have bleeding from the uterus or vagina that is not part of the menstrual cycle or is abnormal. 

Cancer. Premarin should not be used if you have, suspect, or had breast cancer or have a tumor or cancer that is sensitive to estrogen. These conditions could worsen if you take Premarin.

Blood Clots. Premarin should not be used if you have or had blood clots, including a blood clot in the lungs (pulmonary embolism) or deep venous thrombosis (DVT). In addition, the medicine should not be used if you have a condition that makes your blood more prone to forming clots (thrombophilia). Premarin can increase the risk of having a blood clot that could be dangerous, even fatal.

Heart Attack or Stroke. Premarin should not be used if you have or had a stroke or heart attack. Premarin can increase the risk of having a heart attack or stroke that could be dangerous, even fatal.

Liver Problems. Premarin should not be used if your liver is not working as well as it should be. If there is a concern about the health of your liver, your health care provider may do tests to see if it is working well enough to take this medicine.

Pregnancy. Do not take Premarin if you are pregnant or think you may be pregnant. If you become pregnant, contact your health care provider right away. See the Pregnancy section for more details.

What should I know about Premarin before using it?

Do not take Premarin unless it has been prescribed to you by a health care provider. Take it as prescribed.

Do not share Premarin with other people, even if they have the same condition as you. It may harm them.

Keep Premarin out of the reach of children.

You should try to take Premarin at about the same time each day. 

You may sometimes notice something in your stool (poop) that looks like a Premarin tablet. If this happens, tell your health care provider. 

People who are 65 and older can be at greater risk of some side effects from Premarin. Talk to your health care provider about your risks if you are in this age group.

Make sure to keep all follow-up appointments with your health care provider. They will use these appointments to check if your dose or medicine needs to be changed. Estrogen-containing medicines should be used at the lowest possible dose for only as long as it is needed.

Perform monthly self-breast exams and have regular pelvic exams (female exam), breast exams (done by a health care provider), and mammograms (X-ray to look closely at breast tissue) before taking Premarin and during treatment with it. Follow your health care provider’s recommendations for these.

Your health care provider may prescribe other hormonal medicines with Premarin. This is done in some cases to reduce cancer risk if you have a uterus. 

Premarin may cause some laboratory tests to give a false reading, including thyroid function tests, certain hormone tests, and cholesterol blood tests. Talk to your health care provider if you have any concerns.

What should I tell my health care provider before using Premarin?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if Premarin is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

Tobacco Use. Smoking and tobacco use can increase your risk of getting heart disease, which increases your risk of having a heart attack, stroke, or blood clots. Tell your health care provider if you use any tobacco products before starting Premarin.

Upcoming Surgery or Bed Rest. You may be at an increased risk for some side effects of Premarin if you do not move around normally for an extended period of time. Tell your health care provider if you have any upcoming surgeries or need to be on bed rest. Your health care provider can tell you if or when you need to stop taking Premarin.

Contact Lenses. Premarin may make it hard to wear contact lenses. Tell your health care provider if you become sensitive or intolerant to wearing them while taking Premarin.

High Triglyceride Levels. If you have high triglyceride levels, Premarin may increase your triglyceride levels even further. Very high triglyceride levels can lead to inflammation of the pancreas, which is called pancreatitis. Tell your health care provider if you have high triglyceride levels.

Uterine Fibroids. If you have benign tumors (fibroids) in your uterus, Premarin may cause them to get bigger. Some fibroids are small and cause no symptoms, while others may grow and cause problems. Talk to your health care provider if you have any of the following symptoms.

  • Heavy, long, painful periods
  • Pain in the lower belly or back
  • Painful sex
  • Peeing often 
  • Discomfort in the rectum

Pregnancy. Premarin should not be taken during pregnancy. Tell your health care provider if you are pregnant, think you may be pregnant, or plan to become pregnant. If you become pregnant while taking Premarin, stop taking it right away and contact your health care provider.

Breastfeeding. Premarin passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should stop breastfeeding or stop Premarin.

How can I get more information about Premarin?

For more information about Premarin, you can visit the drugmaker’s website at www.premarin.com or call them at 800-505-4426.

Interactions

Does Premarin interact with foods or drinks?

Eating grapefruit or drinking grapefruit juice while taking Premarin can increase the level of estrogens in your body. Talk to your health care provider if you eat grapefruit or drink grapefruit juice. 

It is unknown if drinking alcohol will affect Premarin. 

Does Premarin interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking Premarin.

  • St. John’s wort, which is a supplement that may be used for depression
  • Phenobarbital, which is a medicine that may be used for seizures
  • Carbamazepine (Carbatrol, Tegretol, and others), which is a medicine commonly used to treat seizures or nerve pain
  • Rifampin (Rifadin), which is a medicine commonly used to treat an infection called tuberculosis
  • Clarithromycin or erythromycin (Ery-Tab and others), which are medicines used for bacterial infections
  • Itraconazole (Sporanox, Tolsura) or ketoconazole, which are medicines used for fungal infections
  • Ritonavir (Norvir), which is a medicine commonly used to treat HIV

Some other medicines may alter the blood levels of Premarin. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with Premarin. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much Premarin?

If you or someone else has used too much Premarin, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of Premarin?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.