What the label lists and what reports show
Elacestrant side effects
Elacestrant's FDA label: “The most common (>10%) adverse reactions, including laboratory abnormalities, of ORSERDU were musculoskeletal pain, nausea, increased cholesterol, increased AST, increased triglycerides, fatigue, decreased hemoglobin, vomiting, increased ALT, decreased …” FAERS holds 7,117 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is nausea (1,501 reports).
- No generic listed
Check it at the source: the elacestrant FDA label on DailyMed (effective June 24, 2026, Stemline Therapeutics, Inc.); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of ORSERDU?ORSERDU may cause serious side effects, including: Increased fat (lipid) levels in your blood (hypercholesterolemia and hypertriglyceridemia). Your healthcare provider will do blood tests to check your lipid levels before and during your treatment with ORSERDU. The most common side effects of ORSERDU include: muscle and joint (musculoskeletal) pain nausea increased cholesterol and triglyceride levels in your blood increased liver function tests tiredness decreased red blood cell counts vomiting decreased salt (sodium) levels in your blood increased kidney function test decreased appetite diarrhea headache constipation stomach-area (abdominal) pain hot flush indigestion or heartburn Your healthcare provider may decrease your dose, temporarily stop, or completely stop treatment with ORSERDU, if you develop certain side effects. […]
Source: FDA drug label, Stemline Therapeutics, Inc., effective June 24, 2026 (SPL set aa66ae5c-2bd2-4444-8178-b55651e054ef), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common (>10%) adverse reactions, including laboratory abnormalities, of ORSERDU were musculoskeletal pain, nausea, increased cholesterol, increased AST, increased triglycerides, fatigue, decreased hemoglobin, vomiting, increased ALT, decreased sodium, increased creatinine, decreased appetite, diarrhea, headache, constipation, abdominal pain, hot flush, and dyspepsia.
A table the label prints in its adverse reactions section without a title; its column headings name the groups compared
| Reaction | All Grades (%) | Grade 3 or 4 c (%) | All Grades (%) | Grade 3 or 4 c (%) |
|---|---|---|---|---|
| Musculoskeletal pain b | 41 | 7 | 39 | 1 |
| Nausea | 35 | 2.5 | 19 | 0.9 |
| Vomiting b | 19 | 0.8 | 9 | 0 |
| Diarrhea | 13 | 0 | 10 | 1 |
| Constipation | 12 | 0 | 6 | 0 |
| Abdominal pain b | 11 | 1 | 10 | 0.9 |
| Dyspepsia | 10 | 0 | 2.6 | 0 |
| Fatigue b | 26 | 2 | 27 | 1 |
| Decreased appetite | 15 | 0.8 | 10 | 0.4 |
| Headache | 12 | 2 | 12 | 0 |
| Hot flush | 11 | 0 | 8 | 0 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following clinically significant adverse reactions are described elsewhere in the labeling: Dyslipidemia [see Warnings and Precautions ( 5.1 )] The most common (>10%) adverse reactions, including laboratory abnormalities, of ORSERDU were musculoskeletal pain, nausea, increased cholesterol, increased AST, increased triglycerides, fatigue, decreased hemoglobin, vomiting, increased ALT, decreased sodium, increased creatinine, decreased appetite, diarrhea, headache, constipation, abdominal pain, hot flush, and dyspepsia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Stemline Therapeutics, Inc. at 1-877-332-7961 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of ORSERDU was evaluated in 467 patients with ER+/HER2- advanced breast cancer following CDK4/6 inhibitor therapy in EMERALD, a randomized, open-label, multicenter study [see Clinical Studies ( 14 )]. Patients received ORSERDU 345 mg orally once daily (n=237) or standard of care (SOC) consisting of fulvestrant or an aromatase inhibitor (n=230). …
Source: FDA drug label, Stemline Therapeutics, Inc., effective June 24, 2026 (SPL set aa66ae5c-2bd2-4444-8178-b55651e054ef), via openFDA; the full label on DailyMed
What do FAERS reports show?
7,117 reports list elacestrant among the medicines taken, each a report of something that happened, not proof the medicine caused it; 548 are coded as a death and 891 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Reports rose sharply in 2024 (3,661, against a median of 0 a year): FAERS counts follow reporting, which news, litigation and label changes can drive, not how often a reaction happens. Of the 21 reactions below, 10 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Elacestrant: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions