See the DrugPatentWatch profile for filspari
Common Side Effects of Filspari
Filspari (sparsentan), approved for IgA nephropathy, causes peripheral edema in 25% of patients, often mild to moderate and appearing within weeks of starting treatment. Headache affects 18%, hypotension or low blood pressure 14%, dizziness 12%, and diarrhea 11%. Hyponatremia (low sodium) occurs in 10%.[1][2]
Serious Risks and Warnings
Risk of embryo-fetal toxicity requires pregnancy testing and contraception for females of reproductive potential; it's contraindicated in pregnancy. Hepatotoxicity monitoring is needed with monthly liver tests for the first year, then periodically—discontinue if ALT/AST exceeds 3x upper limit with bilirubin rise. Acute kidney injury or worsening renal function can happen, especially early; monitor eGFR closely. Volume depletion from diuretics heightens hypotension risk.[1][2]
Side Effects by Frequency
| Frequency | Side Effects |
|-----------|--------------|
| ≥10% | Peripheral edema, hypotension, dizziness, headache, hyponatremia, diarrhea |
| 5-10% | Fatigue, anemia, hyperkalemia, nausea, viral infections |
| <5% | Increased creatinine, acute kidney injury, rash, syncope, acute liver injury[1][2] |
How Side Effects Compare to Other IgA Nephropathy Drugs
Unlike Tarpeyo (budesonide), which mainly causes upper respiratory infections and hypertension, Filspari's edema and hypotension stem from its dual endothelin/angiotensin receptor blockade, similar to mechanisms in atrasentan but with added RAAS inhibition.2
Patient Monitoring and Management
Check blood pressure, electrolytes, kidney function, and liver enzymes before starting and regularly. Manage edema with dose reduction or diuretics; hold for severe hypotension or liver issues. No routine dose adjustment for mild renal impairment.[1]
What Happens If Side Effects Occur
Mild cases often resolve with monitoring or supportive care. Severe hypotension may need hospitalization; liver enzyme elevations >3x typically prompt discontinuation. Report symptoms like swelling, fatigue, or yellowing skin immediately.[1][2]
[1]: https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/217481s000lbl.pdf (Filspari Prescribing Information)
[2]: https://www.filspari.com/ (Official Product Site)