What the label lists and what reports show
Belumosudil side effects
Belumosudil's FDA label: “The most common (≥20%) adverse reactions, including laboratory abnormalities, are infections, asthenia, nausea, diarrhea, dyspnea, cough, edema, hemorrhage, abdominal pain, musculoskeletal pain, headache, phosphate decreased, gamma glutamyl transferase …” FAERS holds 3,183 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 (257 reports).
- No generic listed
Check it at the source: the belumosudil FDA label on DailyMed (effective April 7, 2026, Kadmon Pharmaceuticals, LLC); 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 REZUROCK?The most common side effects of REZUROCK include: infections tiredness or weakness nausea diarrhea shortness of breath cough swelling bleeding stomach (abdominal) pain muscle or bone pain headache high blood pressure Your healthcare provider may change your dose of REZUROCK, temporarily stop, or permanently stop treatment with REZUROCK if you have certain side effects. REZUROCK may affect fertility in males and females. Talk to your healthcare provider if this is a concern for you. These are not all the possible side effects of REZUROCK. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects to Kadmon Pharmaceuticals, LLC at 1-800-633-1610.
Source: FDA drug label, Kadmon Pharmaceuticals, LLC, effective April 7, 2026 (SPL set 102e4ef4-7f84-4e34-8df1-479c24d1575d), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common (≥20%) adverse reactions, including laboratory abnormalities, are infections, asthenia, nausea, diarrhea, dyspnea, cough, edema, hemorrhage, abdominal pain, musculoskeletal pain, headache, phosphate decreased, gamma glutamyl transferase increased, lymphocytes decreased, and hypertension.
Table 2: Nonlaboratory Adverse Reactions in ≥10% Patients with Chronic GVHD Treated with REZUROCK
| Reaction | Adverse Reaction All Grades (%) | REZUROCK 200 mg once daily (N=83) Grades 3–4 (%) |
|---|---|---|
| Infection (pathogen not specified) infection with an unspecified pathogen includes acute… | 53 | 16 |
| Viral infection includes influenza, rhinovirus infection, gastroenteritis viral, viral… | 19 | 4 |
| Bacterial infection includes cellulitis, Helicobacter infection, Staphylococcal… | 16 | 4 |
| Asthenia includes fatigue, asthenia, malaise. | 46 | 4 |
| Edema includes edema peripheral, generalized edema, face edema, localized edema, edema. | 27 | 1 |
| Pyrexia | 18 | 1 |
| Nausea includes nausea, vomiting. | 42 | 4 |
| Diarrhea | 35 | 5 |
| Abdominal pain includes abdominal pain, abdominal pain upper, abdominal pain lower. | 22 | 1 |
| Dysphagia | 16 | 0 |
| Dyspnea includes dyspnea, dyspnea exertional, apnea, orthopnea, sleep apnea syndrome. | 33 | 5 |
| Cough includes cough, productive cough. | 30 | 0 |
| Nasal congestion | 12 | 0 |
| Hemorrhage includes contusion, hematoma, epistaxis, increased tendency to bruise,… | 23 | 5 |
| Hypertension | 21 | 7 |
| Musculoskeletal pain includes pain in extremity, back pain, flank pain, limb discomfort,… | 22 | 4 |
| Muscle spasm | 17 | 0 |
| Arthralgia | 15 | 2 |
| Headache includes headache, migraine. | 21 | 0 |
| Decreased appetite | 17 | 1 |
| Rash includes rash, rash maculo-papular, rash erythematous, rash generalized, dermatitis… | 12 | 0 |
| Pruritus includes pruritus, pruritus generalized. | 11 | 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 (≥20%) adverse reactions, including laboratory abnormalities, are infections, asthenia, nausea, diarrhea, dyspnea, cough, edema, hemorrhage, abdominal pain, musculoskeletal pain, headache, phosphate decreased, gamma glutamyl transferase increased, lymphocytes decreased, and hypertension. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Kadmon Pharmaceuticals, LLC at 1-800-633-1610 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trial Experience Because clinical trials are conducted under widely variable conditions, adverse reaction rates observed in clinical trials of a drug cannot be directly compared with rates of clinical trials of another drug and may not reflect the rates observed in practice. Chronic Graft versus Host Disease In two clinical trials (Study KD025-213 and Study KD025-208), 83 adult patients with chronic GVHD were treated with REZUROCK 200 mg once daily [see Clinical Studies (14.1) ]. The median duration of treatment was 9.2 months (range 0.5 to 44.7 months). Fatal adverse reaction was reported in one patient with severe nausea, vomiting, diarrhea and multi-organ failure. Permanent discontinuation of REZUROCK due to adverse reactions occurred in 18% of patients. The adverse reactions which resulted in permanent discontinuation of REZUROCK in >3% of patients included nausea (4%). …
Source: FDA drug label, Kadmon Pharmaceuticals, LLC, effective April 7, 2026 (SPL set 102e4ef4-7f84-4e34-8df1-479c24d1575d), via openFDA; the full label on DailyMed
What do FAERS reports show?
3,183 reports list belumosudil among the medicines taken, each a report of something that happened, not proof the medicine caused it; 287 are coded as a death and 816 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 16 reactions below, 11 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?
- Belumosudil: 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