What the label lists and what reports show
Enzalutamide side effects
Enzalutamide's FDA label: “The most common adverse reactions (≥ 10%) that occurred more frequently (≥ 2% over placebo) in the XTANDI-treated patients are musculoskeletal pain, fatigue, hot flush, constipation, decreased appetite, diarrhea, hypertension, hemorrhage, fall, fracture, and …” FAERS holds 58,437 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 fatigue (10,267 reports).
- No generic listed
Check it at the source: the enzalutamide FDA label on DailyMed (effective July 28, 2026, Astellas Pharma US, 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 XTANDI?XTANDI may cause serious side effects including: • Seizure. If you take XTANDI you may be at risk of having a seizure. You should avoid activities where a sudden loss of consciousness could cause serious harm to yourself or others. Tell your healthcare provider right away if you have loss of consciousness or seizure. • Posterior Reversible Encephalopathy Syndrome (PRES). If you take XTANDI you may be at risk of developing a condition involving the brain called PRES. Tell your healthcare provider right away if you have a seizure or quickly worsening symptoms such as headache, decreased alertness, confusion, reduced eyesight, blurred vision or other visual problems. Your healthcare provider will do a test to check for PRES. • Allergic Reactions. Allergic reactions have happened in people who take XTANDI. […]
Source: FDA drug label, Astellas Pharma US, Inc., effective July 28, 2026 (SPL set b129fdc9-1d8e-425c-a5a9-8a2ed36dfbdf), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common adverse reactions (≥ 10%) that occurred more frequently (≥ 2% over placebo) in the XTANDI-treated patients are musculoskeletal pain, fatigue, hot flush, constipation, decreased appetite, diarrhea, hypertension, hemorrhage, fall, fracture, and headache.
Table 1. Adverse Reactions in AFFIRM
| Reaction | Grade 1-4 CTCAE v 4. (%) | Grade 3-4 (%) | Grade 1-4 (%) | Grade 3-4 (%) |
|---|---|---|---|---|
| Asthenic Conditions Includes asthenia and fatigue. | 51 | 9 | 44 | 9 |
| Peripheral Edema | 15 | 1 | 13 | 0.8 |
| Back Pain | 26 | 5 | 24 | 4 |
| Arthralgia | 21 | 2.5 | 17 | 1.8 |
| Musculoskeletal Pain | 15 | 1.3 | 12 | 0.3 |
| Muscular Weakness | 10 | 1.5 | 7 | 1.8 |
| Musculoskeletal Stiffness | 2.6 | 0.3 | 0.3 | 0 |
| Diarrhea | 22 | 1.1 | 18 | 0.3 |
| Hot Flush | 20 | 0 | 10 | 0 |
| Hypertension | 6 | 2.1 | 2.8 | 1.3 |
| Headache | 12 | 0.9 | 5 | 0 |
| Dizziness Includes dizziness and vertigo. | 9 | 0.5 | 7 | 0.5 |
| Spinal Cord Compression and Cauda Equina Syndrome | 7 | 7 | 4.5 | 3.8 |
| Paresthesia | 7 | 0 | 4.5 | 0 |
| Mental Impairment Disorders Includes amnesia, memory impairment, cognitive disorder, and… | 4.3 | 0.3 | 1.8 | 0 |
| Hypoesthesia | 4 | 0.3 | 1.8 | 0 |
| Upper Respiratory Tract Infection Includes nasopharyngitis, upper respiratory tract… | 11 | 0 | 6 | 0.3 |
| Lower Respiratory Tract and Lung Infection Includes pneumonia, lower respiratory tract… | 8 | 2.4 | 4.8 | 1.3 |
| Insomnia | 9 | 0 | 6 | 0.5 |
| Anxiety | 6 | 0.3 | 4 | 0 |
| Hematuria | 7 | 1.8 | 4.5 | 1 |
| Pollakiuria | 4.8 | 0 | 2.5 | 0 |
| Fall | 4.6 | 0.3 | 1.3 | 0 |
| Non-pathologic Fractures | 4 | 1.4 | 0.8 | 0.3 |
| Pruritus | 3.8 | 0 | 1.3 | 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 adverse reactions are discussed in more detail in other sections of the labeling: • Seizure [see Warnings and Precautions ( 5.1 )] • Posterior Reversible Encephalopathy Syndrome (PRES) [see Warnings and Precautions ( 5.2 )] • Hypersensitivity [see Warnings and Precautions ( 5.3 )] • Ischemic Heart Disease [see Warnings and Precautions ( 5.4 )] • Falls and Fractures [see Warnings and Precautions ( 5.5 )] • Dysphagia or Choking [see Warnings and Precautions ( 5.7 )] The most common adverse reactions (≥ 10%) that occurred more frequently (≥ 2% over placebo) in the XTANDI-treated patients are musculoskeletal pain, fatigue, hot flush, constipation, decreased appetite, diarrhea, hypertension, hemorrhage, fall, fracture, and headache. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Astellas Pharma US, Inc. at 1-800-727-7003 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trial 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. …
Source: FDA drug label, Astellas Pharma US, Inc., effective July 28, 2026 (SPL set b129fdc9-1d8e-425c-a5a9-8a2ed36dfbdf), via openFDA; the full label on DailyMed
What do FAERS reports show?
58,437 reports list enzalutamide among the medicines taken, each a report of something that happened, not proof the medicine caused it; 11,360 are coded as a death and 11,077 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 2017 (10,285, against a median of 2,631 a year): FAERS counts follow reporting, which news, litigation and label changes can drive, not how often a reaction happens. Of the 22 reactions below, 16 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?
- Enzalutamide: 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