What the label lists and what reports show
Erdafitinib side effects
Erdafitinib's FDA label: “The most common (>20%) […]” FAERS holds 1,215 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 diarrhoea (97 reports).
- No generic listed
Check it at the source: the erdafitinib FDA label on DailyMed (effective October 24, 2025, Janssen Products LP); 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 BALVERSA?BALVERSA may cause serious side effects, including: Eye problems. Eye problems are common with BALVERSA but can also be serious. Eye problems include dry or inflamed eyes, inflamed cornea (front part of the eye) and disorders of the retina, an internal part of the eye. Tell your healthcare provider right away if you develop blurred vision, loss of vision or other visual changes. You should use artificial tear substitutes, hydrating or lubricating eye gels or ointments at least every 2 hours during waking hours to help prevent dry eyes. During treatment with BALVERSA, your healthcare provider will send you to see an eye specialist. High phosphate levels in the blood (hyperphosphatemia). Hyperphosphatemia is common with BALVERSA but can also be serious. High levels of phosphate in your blood may lead to build-up of minerals such as calcium in different tissues in your body. […]
Source: FDA drug label, Janssen Products LP, effective October 24, 2025 (SPL set 2a8aa5c0-6c92-4566-8c45-e8f4d1fc20ee), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common (>20%) […]
Table 5: Adverse Reactions Reported in ≥15% of Patients (Study BLC2001)
| Reaction | Adverse Reaction All Grades (%) | BALVERSA 8 mg daily (N=87) Grade 3–4 (%) |
|---|---|---|
| Stomatitis Includes multiple terms | 62 | 11 |
| Diarrhea | 48 | 4.6 |
| Dry mouth | 45 | 0 |
| Constipation | 28 | 1.1 |
| Nausea | 21 | 1.1 |
| Nail disorders | 62 | 14 |
| Dry skin | 37 | 0 |
| Alopecia | 26 | 0 |
| Palmar-plantar erythrodysesthesia syndrome | 26 | 6 |
| Fatigue , Includes fatal adverse reactions (n=2) | 54 | 8 |
| Decreased weight | 16 | 0 |
| Decreased appetite | 38 | 0.0 |
| Dysgeusia | 38 | 1.1 |
| Dry eye | 29 | 1.1 |
| Central serous retinopathy | 28 | 4.6 |
| Blurred vision | 17 | 0 |
| Urinary tract infection | 17 | 6 |
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 serious adverse reactions are also described elsewhere in the labeling: Ocular Disorders [see Warnings and Precautions (5.1) ]. Hyperphosphatemia [see Warnings and Precautions (5.2) ]. The most common (>20%) adverse reactions, including laboratory abnormalities, were increased phosphate, nail disorders, stomatitis, diarrhea, increased creatinine, increased alkaline phosphatase, increased alanine aminotransferase, decreased hemoglobin, decreased sodium, increased aspartate aminotransferase, fatigue, dry mouth, dry skin, decreased phosphate, decreased appetite, dysgeusia, constipation, increased calcium, dry eye, palmar-plantar erythrodysesthesia syndrome, increased potassium, alopecia, and central serous retinopathy. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Janssen Products, LP. at 1-800-526-7736 (1-800-JANSSEN and www.BALVERSA.com) 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. …
Source: FDA drug label, Janssen Products LP, effective October 24, 2025 (SPL set 2a8aa5c0-6c92-4566-8c45-e8f4d1fc20ee), via openFDA; the full label on DailyMed
What do FAERS reports show?
1,215 reports list erdafitinib among the medicines taken, each a report of something that happened, not proof the medicine caused it; 342 are coded as a death and 256 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 21 reactions below, 12 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?
- Erdafitinib: 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