Prescription medication · Conjugated Estrogen
conjugated estrogens
Also sold as Premarin. Premarin Intravenous treats unusual bleeding from the uterus when it's caused by hormone problems and not by other health issues.
Data updated 2026-05-15
- 57,675
- FDA reportsOften reported
- 1
- InteractionFew interactions
- $6.62
- Brand price (NADAC)
What the data shows
conjugated estrogens (Premarin) is a prescription Conjugated Estrogen, more reported than most tracked drugs (57,675 FDA reports), with 1 documented drug interaction.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
conjugated estrogens (Premarin) is a prescription Conjugated Estrogen. Premarin Intravenous treats unusual bleeding from the uterus when it's caused by hormone problems and not by other health issues.
Premarin Intravenous is an injectable medicine that contains estrogen hormones. It is used to quickly raise estrogen levels for a short time.
Verify with FDA → · CMS NADAC pricing →
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.
The sections below are summarized in plain English from conjugated estrogens's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
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.
This is a plain-language summary of conjugated estrogens's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
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.
This is a plain-language summary of conjugated estrogens's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
Since a healthcare provider gives you this medicine, you are unlikely to miss a dose.
This is a plain-language summary of conjugated estrogens's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed 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 57,675 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for conjugated estrogens, by number of reports
- Breast cancer
Breast cancer
9,622 reports
- Breast cancer in women
Breast cancer in women
8,862 reports
- Feeling sick to your stomach 2,360
Feeling sick to your stomach
2,360 reports
- Head pain 2,290
Head pain
2,290 reports
- Pain 2,246
Pain
2,246 reports
- Feeling tired 2,197
Feeling tired
2,197 reports
- Breast cancer that has spread 1,682
Breast cancer that has spread
1,682 reports
- Feeling lightheaded 1,630
Feeling lightheaded
1,630 reports
- Difficulty breathing 1,612
Difficulty breathing
1,612 reports
- Feeling unwell 1,572
Feeling unwell
1,572 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for conjugated estrogens each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where conjugated estrogens sits
conjugated estrogens has more FDA adverse-event reports than 76% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is conjugated estrogens; the line is the median (50th percentile).
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
Reports Mentioning Death
1,777
3.1% of reports — not proof of cause
Hospitalization Reports
9,226
Top Indication
Hormone Replacement Therapy
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | BREAST CANCER | 9,623 |
| 2 | BREAST CANCER FEMALE | 8,862 |
| 4 | NAUSEA | 2,360 |
| 5 | HEADACHE | 2,291 |
| 6 | PAIN | 2,248 |
| 7 | FATIGUE | 2,198 |
| 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 |
| 16 | DEPRESSION | 1,402 |
| 17 | INSOMNIA | 1,287 |
Reactions in Death Reports
Reactions in Hospitalization Reports
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.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
What is Premarin Intravenous used for?
How is Premarin Intravenous given?
Can I use Premarin Intravenous if I have breast cancer?
What should I do if I experience side effects?
Can I use Premarin Intravenous if I am pregnant?
How often will I receive the injection?
Does Premarin Intravenous prevent heart disease or dementia?
What should I tell my doctor before using Premarin Intravenous?
Can Premarin Intravenous cause blood clots?
How should I store Premarin Intravenous before it is mixed?
What are the common side effects of conjugated estrogens?
Does conjugated estrogens interact with other medications?
What drug class is conjugated estrogens?
Is conjugated estrogens safe during pregnancy?
Related Medications in Conjugated Estrogen
Other drugs grouped near conjugated estrogens - same-class peers and common alternatives.
abiraterone
Zytiga
Abiraterone (Zytiga) is a medicine used with prednisone to treat prostate cancer that has spread.
Compare with conjugated estrogens →
anastrozole
Arimidex
Anastrozole is a medicine used to treat breast cancer in women after menopause.
Compare with conjugated estrogens →
bazedoxifene/conjugated estrogens
Duavee
Duavee is a combination medicine containing estrogen and a drug that blocks estrogen in some parts of the body.
Compare with conjugated estrogens →
cabergoline
Dostinex
Cabergoline is a medicine that helps lower the amount of prolactin in your body.
Compare with conjugated estrogens →
clomiphene
Clomid, Serophene
Clomiphene citrate is a medicine that helps women ovulate.
Compare with conjugated estrogens →
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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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 57,675 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
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages