Losartan and Sparsentan: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Losartan
Sparsentan
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
An increased risk of hypotension, syncope, hyperkalemia, and changes in renal function (including acute renal failure), reduced CYP2C9 substrate exposure and reduced efficacy of CYP2C9 substrate
Interaction Deep Dive
Coadministration of sparsentan and ARBs that are also CYP2C9 substrates is contraindicated due to the potential for increased risk of hypotension, syncope, hyperkalemia, and changes in renal function (including acute renal failure). Concomitant administration may also reduce CYP2C9 substrates exposure of these substrates, which may reduce the efficacy of CYP2C9 substrates. If coadministered, monitor for efficacy of these substrates and consider dosage adjustment as required1.
Why it happens (mechanism)
Unknown; induction of CYP2C9-substrate metabolism by sparsentan
Common questions
Can I take Losartan and Sparsentan together?
An increased risk of hypotension, syncope, hyperkalemia, and changes in renal function (including acute renal failure), reduced CYP2C9 substrate exposure and reduced efficacy of CYP2C9 substrate Always confirm with your pharmacist or prescriber before making any change.
How serious is the Losartan and Sparsentan interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Losartan or Sparsentan need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (1)
- Product Information: FILSPARI(R) oral tablets, sparsentan oral tablets. Travere Therapeutics Inc (per FDA), San Diego, CA, 2024. DailyMed
Keep reading about Losartan
Keep reading about Sparsentan
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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