What the label lists and what reports show
Eribulin side effects
Eribulin's FDA label: “The most common adverse reactions (≥25%) in metastatic breast cancer were neutropenia, anemia, asthenia/fatigue, alopecia, peripheral neuropathy, nausea, and constipation.” FAERS holds 3,719 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 neutropenia (537 reports).
- Generic listed
Check it at the source: the eribulin FDA label on DailyMed (effective November 7, 2025, Eisai 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 HALAVEN?HALAVEN may cause serious side effects, including: See “ What is the most important information I should know about HALAVEN?” HALAVEN can cause changes in your heartbeat ( called QT prolongation ). This can cause irregular heartbeats. Your healthcare provider may do heart monitoring (electrocardiogram or ECG) or blood tests during your treatment with HALAVEN to check for heart problems. The most common side effects of HALAVEN in people with breast cancer include: low white blood cell count (neutropenia) low red blood cell count (anemia) weakness or tiredness hair loss (alopecia) nausea constipation The most common side effects of HALAVEN in people with liposarcoma include: tiredness nausea hair loss (alopecia) constipation stomach pain fever Your healthcare provider will do blood tests before and during treatment while you are taking HALAVEN. […]
Source: FDA drug label, Eisai Inc., effective November 7, 2025 (SPL set 31ce4750-ded5-4a0b-95e9-f229fa6bc822), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common adverse reactions (≥25%) in metastatic breast cancer were neutropenia, anemia, asthenia/fatigue, alopecia, peripheral neuropathy, nausea, and constipation.
Table 2: Adverse Reactions a with a Per-Patient Incidence of at Least 10% in Study 1
| Reaction | All Grades | ≥ Grade 3 | All Grades | ≥ Grade 3 |
|---|---|---|---|---|
| Neutropenia | 82% | 57% | 53% | 23% |
| Anemia | 58% | 2% | 55% | 4% |
| Peripheral neuropathy c | 35% | 8% | 16% | 2% |
| Headache | 19% | <1% | 12% | <1% |
| Asthenia/Fatigue | 54% | 10% | 40% | 11% |
| Pyrexia | 21% | <1% | 13% | <1% |
| Mucosal inflammation | 9% | 1% | 10% | 2% |
| Nausea | 35% | 1% | 28% | 3% |
| Constipation | 25% | 1% | 21% | 1% |
| Vomiting | 18% | 1% | 18% | 1% |
| Diarrhea | 18% | 0 | 18% | 0 |
| Arthralgia/Myalgia | 22% | <1% | 12% | 1% |
| Back pain | 16% | 1% | 7% | 2% |
| Bone pain | 12% | 2% | 9% | 2% |
| Pain in extremity | 11% | 1% | 10% | 1% |
| Decreased weight | 21% | 1% | 14% | <1% |
| Anorexia | 20% | 1% | 13% | 1% |
| Dyspnea | 16% | 4% | 13% | 4% |
| Cough | 14% | 0 | 9% | 0 |
| Alopecia | 45% | NA d | 10% | NA d |
| Urinary Tract Infection | 10% | 1% | 5% | 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 most common adverse reactions (≥25%) in metastatic breast cancer were neutropenia, anemia, asthenia/fatigue, alopecia, peripheral neuropathy, nausea, and constipation. ( 6.1 ) The most common adverse reactions (≥25%) in liposarcoma and leiomyosarcoma were fatigue, nausea, alopecia, constipation, peripheral neuropathy, abdominal pain, and pyrexia. The most common (≥5%) Grade 3-4 laboratory abnormalities in liposarcoma and leiomyosarcoma were neutropenia, hypokalemia, and hypocalcemia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Eisai Inc. at (1-877-873-4724) 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, the adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in other clinical trials and may not reflect the rates observed in clinical practice. The following adverse reactions are discussed in detail in other sections of the labeling: Neutropenia [ see Warnings and Precautions (5.1) ] Peripheral neuropathy [see Warnings and Precautions (5.2)] QT prolongation [see Warnings and Precautions (5.4) ] In clinical trials, HALAVEN has been administered to 1963 patients including 467 patients exposed to HALAVEN for 6 months or longer. …
Source: FDA drug label, Eisai Inc., effective November 7, 2025 (SPL set 31ce4750-ded5-4a0b-95e9-f229fa6bc822), via openFDA; the full label on DailyMed
What do FAERS reports show?
3,719 reports list eribulin among the medicines taken, each a report of something that happened, not proof the medicine caused it; 659 are coded as a death and 1,947 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. Of the 24 reactions below, 17 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?
- Eribulin: 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