Sitaxsentan and Cyclosporine Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cyclosporine Injection
Sitaxsentan
No brand names on record
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
Increased sitaxsentan plasma concentrations
Interaction Deep Dive
Concomitant use of cycloSPORINE and sitaxsentan is contraindicated as this has resulted in a significant increase in sitaxsentan plasma concentrations in pharmacokinetic studies. The manufacturer postulates that sitaxsentan is an organic anion-transporting polypeptide (OATP) substrate that is inhibited by cycloSPORINE, a potent inhibitor of OATP1.
Why it happens (mechanism)
Unknown
Literature reports
1 report — tap to read
a) In pharmacokinetic studies with sitaxsentan, the concomitant use of cycloSPORINE 3.5 mg/kg twice daily and sitaxsentan 100 mg once daily resulted in a 6-fold increase in the pre-dose sitaxsentan sodium concentrations. CycloSPORINE pharmacokinetics were not significantly altered 1.
Common questions
Can I take Sitaxsentan and Cyclosporine Injection together?
Increased sitaxsentan plasma concentrations Always confirm with your pharmacist or prescriber before making any change.
How serious is the Sitaxsentan and Cyclosporine Injection 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 "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Sitaxsentan or Cyclosporine Injection 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: THELIN(R) Australia oral tablets, sitaxentan sodium oral tablets. CSL Limited, Victoria, Australia, 2008.
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