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conjugated estrogens

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Brand names: Premarin

Conjugated Estrogen Rx

Premarin Intravenous is an injectable medicine that contains estrogen hormones. It is used to quickly raise estrogen levels for a short time.

Drug Pricing (NADAC)

Brand Price

$6.62/unit

Generic Available

No

WYETH PHARMS

Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →

What it does

Premarin Intravenous treats unusual bleeding from the uterus when it's caused by hormone problems and not by other health issues.

Common side effects

Nausea, Headache, Dizziness

Key warnings

Estrogen-alone therapy can increase the risk of uterine cancer, stroke, blood clots, and dementia.

How It Works

Premarin Intravenous contains estrogen hormones. These hormones help to control the menstrual cycle. By providing estrogen, it can help stop abnormal uterine bleeding caused by a hormone imbalance.

How to Take It

A healthcare provider will give you Premarin Intravenous as an injection into a vein or muscle. The usual dose is one 25 mg injection. If needed, the injection can be repeated in 6 to 12 hours. The injection should be given slowly to prevent flushing.

Pregnancy & Breastfeeding

You should not use Premarin Intravenous if you are pregnant or think you might be pregnant. Talk to your doctor if you are breastfeeding before using this medicine.

Missed Dose

Since a healthcare provider gives you this medicine, you are unlikely to miss a dose.

Storage

Store the package in the refrigerator between 36° to 46°F (2° to 8°C) before mixing.

Side Effects (from patient reports)

Based on 36,338 FDA adverse event reports.

Breast cancer
9,622
Breast cancer in women
8,862
The medicine did not work
3,281
Feeling sick to your stomach
2,360
Head pain
2,290
Pain
2,246
Feeling tired
2,197
Using the medicine for something it's not approved for
2,168
Breast cancer that has spread
1,682
Feeling lightheaded
1,630

FDA Adverse Event Report Analysis

Detailed analysis of 57,675 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 1996–2025.

Total Reports

57,675

Death-Related Reports

1,777

Hospitalization Reports

9,226

Top Indication

Hormone Replacement Therapy

Gender Distribution

Female 55,235 (99%)
Male 187 (0%)

Age Distribution

0–17 185
18–44 1,413
45–64 15,624
65–74 7,558
75+ 4,507

Most Reported Adverse Reactions (FAERS)

# Reaction Reports
1 BREAST CANCER 9,623
2 BREAST CANCER FEMALE 8,862
3 DRUG INEFFECTIVE 3,280
4 NAUSEA 2,360
5 HEADACHE 2,291
6 PAIN 2,248
7 FATIGUE 2,198
8 OFF LABEL USE 2,168
9 BREAST CANCER METASTATIC 1,681
10 DIZZINESS 1,632
11 DYSPNOEA 1,614
12 MALAISE 1,573
13 DIARRHOEA 1,521
14 ARTHRALGIA 1,438
15 ANXIETY 1,421

Reactions in Death Reports

DEATH 386
BREAST CANCER METASTATIC 206
BREAST CANCER 172
BREAST CANCER FEMALE 149
PNEUMONIA 105
MYOCARDIAL INFARCTION 104
CARDIAC ARREST 100
CEREBROVASCULAR ACCIDENT 82
OVARIAN CANCER 79
RENAL FAILURE 77

Reactions in Hospitalization Reports

BREAST CANCER 857
NAUSEA 781
PAIN 760
DYSPNOEA 759
FALL 722
FATIGUE 700
CHEST PAIN 622
DEPRESSION 617
DIARRHOEA 615
HYPERTENSION 612

Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation

Serious Warnings

Estrogen-alone therapy can increase the risk of uterine cancer, stroke, blood clots, and dementia. Estrogen with progestin can increase the risk of blood clots, stroke, heart attack, and dementia. Use the lowest dose for the shortest time needed.

Known Drug Interactions

Concomitant administration of itraconazole, a strong CYP3A4 inhibitor, with DUAVEE, resulted in increases in bazedoxifene exposure (40%) and, to a lesser extent, conjugated estrogens exposure (9% for baseline-adjusted total estrone, 5% for total equilin), compared to DUAVEE alone [see Pharmacokinetics (12.3) ] .

Mechanism: Itraconazole slows down how your body processes this medication, which can cause the levels of the drug in your blood to rise.

What to do: Talk to your doctor about whether you need to watch for increased side effects while taking these together.

Common Questions

What is Premarin Intravenous used for?
It is used to treat abnormal uterine bleeding due to hormonal imbalance.
How is Premarin Intravenous given?
It is given as an injection into a vein or muscle by a healthcare provider.
Can I use Premarin Intravenous if I have breast cancer?
No, you should not use it if you have known, suspected, or a history of breast cancer.
What should I do if I experience side effects?
Tell your healthcare provider about any side effects you experience.
Can I use Premarin Intravenous if I am pregnant?
No, it is not for use during pregnancy.
How often will I receive the injection?
You may receive one 25 mg injection, repeated in 6 to 12 hours if needed.
Does Premarin Intravenous prevent heart disease or dementia?
No, it should not be used to prevent heart disease or dementia.
What should I tell my doctor before using Premarin Intravenous?
Tell your doctor about all your medical conditions and medications you are taking.
Can Premarin Intravenous cause blood clots?
Yes, it can increase the risk of blood clots.
How should I store Premarin Intravenous before it is mixed?
Store it in the refrigerator between 36° to 46°F (2° to 8°C).
What are the common side effects of conjugated estrogens?
The most commonly reported side effects of conjugated estrogens include Nausea, Headache, Dizziness, Joint pain, Anxiety. Based on 36,338 FDA adverse event reports. Always consult your healthcare provider about potential side effects.
Does conjugated estrogens interact with other medications?
Yes, conjugated estrogens has 1 known drug interactions. Notable interactions include bazedoxifene/conjugated estrogens. Always inform your doctor about all medications you are taking.
What drug class is conjugated estrogens?
conjugated estrogens belongs to the Conjugated Estrogen drug class. It requires a prescription (Rx). Premarin Intravenous treats unusual bleeding from the uterus when it's caused by hormone problems and not by other health issues.
Is conjugated estrogens safe during pregnancy?
You should not use Premarin Intravenous if you are pregnant or think you might be pregnant. Talk to your doctor if you are breastfeeding before using this medicine. Always consult your healthcare provider before using any medication during pregnancy or breastfeeding.

Related Medications in Conjugated Estrogen

Other drugs grouped near conjugated estrogens — same-class peers and common alternatives.

Compare conjugated estrogens vs abiraterone side-by-side →

Medication Guides

Related Health & Safety Data

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What the FDA Data Shows for conjugated estrogens

The FDA label for conjugated estrogens (sold under brand names such as Premarin) classifies it as a prescription-only medication in the Conjugated Estrogen class. Premarin Intravenous treats unusual bleeding from the uterus when it's caused by hormone problems and not by other health issues. Official labeling lists 8 commonly reported side effects, including Nausea, Headache, Dizziness.

Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 36,338 voluntary reports. The database also lists 1 documented drug interaction derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS.

Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.

Data Sources

Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).

FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.

Last updated: May 30, 2025

All federal data sources used on this page