What the label lists and what reports show
Pralsetinib side effects
Pralsetinib's FDA label: “The most common adverse reactions (≥ 25%) were musculoskeletal pain, constipation, hypertension, diarrhea, fatigue, edema, pyrexia and cough.” FAERS holds 1,788 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 (126 reports).
- No generic listed
- Boxed warning
Check it at the source: the pralsetinib FDA label on DailyMed (effective December 30, 2025, Rigel Pharmaceuticals, 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 GAVRETO?GAVRETO may cause serious side effects, including: See "What is the most important information I should know about GAVRETO?" Lung problems. GAVRETO may cause severe or life-threatening inflammation of the lungs during treatment, that can lead to death. Tell your healthcare provider right away if you have any new or worsening symptoms, including: shortness of breath cough fever High blood pressure (hypertension). High blood pressure is common with GAVRETO and may sometimes be severe. You should check your blood pressure regularly during treatment with GAVRETO. Tell your healthcare provider if you have increased blood pressure readings or get any symptoms of high blood pressure, including: confusion headaches shortness of breath dizziness chest pain Liver problems. […]
Source: FDA drug label, Rigel Pharmaceuticals, Inc., effective December 30, 2025 (SPL set 16edd46e-28b8-f06d-e063-6394a90ae31b), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common adverse reactions (≥ 25%) were musculoskeletal pain, constipation, hypertension, diarrhea, fatigue, edema, pyrexia and cough.
Table 7: Adverse Reactions (≥ 15%) in RET-altered Thyroid Cancer Patients Who Received GAVRETO in ARROW
| Reaction | Adverse Reactions Grades 1-4 (%) | GAVRETO N=138 Grades 3-4 (%) |
|---|---|---|
| Musculoskeletal Pain Musculoskeletal Pain includes arthralgia, arthritis, back pain, bone… | 42 | 0.7 Only includes a Grade 3 adverse reaction |
| Constipation | 41 | 0.7 |
| Diarrhea Diarrhea includes colitis, diarrhea | 34 | 5 |
| Abdominal Pain Abdominal Pain includes abdominal discomfort, abdominal pain, abdominal… | 17 | 0.7 |
| Dry mouth | 17 | 0 |
| Stomatitis Stomatitis includes mucosal inflammation, stomatitis, tongue ulceration | 17 | 0.7 |
| Nausea | 17 | 0.7 |
| Hypertension | 40 | 21 |
| Fatigue Fatigue includes asthenia, fatigue | 38 | 6 |
| Edema Edema includes eyelid edema, face edema, edema, edema peripheral, periorbital edema | 29 | 0 |
| Pyrexia | 22 | 2.2 |
| Cough Cough includes cough, productive cough, upper-airway cough syndrome | 27 | 1.4 |
| Dyspnea Dyspnea includes dyspnea, dyspnea exertional | 22 | 2.2 |
| Headache Headache includes headache, migraine | 24 | 0 |
| Peripheral Neuropathy Peripheral neuropathy includes dysaesthesia, hyperaesthesia,… | 20 | 0 |
| Dizziness Dizziness includes dizziness, dizziness postural, vertigo | 19 | 0.7 |
| Dysgeusia Dysgeusia includes ageusia, dysgeusia | 17 | 0 |
| Rash Rash includes dermatitis, dermatitis acneiform, eczema, palmar-plantar,… | 24 | 0 |
| Decreased Appetite | 15 | 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: Serious Infections, Including Opportunistic Infections [see Warnings and Precautions (5.1) ] Interstitial Lung Disease/Pneumonitis [see Warnings and Precautions (5.2) ] Hypertension [see Warnings and Precautions (5.3) ] Hepatotoxicity [see Warnings and Precautions (5.4) ] Hemorrhagic Events [see Warnings and Precautions (5.5) ] Tumor Lysis Syndrome [see Warnings and Precautions (5.6) ] Risk of Impaired Wound Healing [see Warnings and Precautions (5.7) ] Embryo-Fetal Toxicity [see Warnings and Precautions (5.8) ] The most common adverse reactions (≥ 25%) were musculoskeletal pain, constipation, hypertension, diarrhea, fatigue, edema, pyrexia and cough. The most common Grade 3-4 laboratory abnormalities (≥ 2%) were decreased lymphocytes, decreased neutrophils, decreased hemoglobin, decreased phosphate, decreased leukocytes, decreased sodium, increased aspartate aminotransferase (AST), increased alanine aminotransferase (ALT), decreased calcium (corrected), decreased platelets, increased alkaline phosphatase, increased potassium, decreased potassium and increased bilirubin.
Source: FDA drug label, Rigel Pharmaceuticals, Inc., effective December 30, 2025 (SPL set 16edd46e-28b8-f06d-e063-6394a90ae31b), via openFDA; the full label on DailyMed
What do FAERS reports show?
1,788 reports list pralsetinib among the medicines taken, each a report of something that happened, not proof the medicine caused it; 252 are coded as a death and 520 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 19 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?
- Pralsetinib: 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