Irinotecan Injection and Posaconazole: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Posaconazole
Irinotecan Injection
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 irinotecan exposure and an increased irinotecan active metabolite exposure
Interaction Deep Dive
Avoid coadministration of irinotecan (a CYP3A4 substrate) with a strong CYP3A4 inhibitor unless there are no therapeutic alternatives, as concomitant use may result in an increased exposure to irinotecan or its active metabolite, SN-38. Discontinue strong CYP3A4 inhibitors at least 1 week prior to initiating therapy with irinotecan21.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of irinotecan
Common questions
Can I take Irinotecan Injection and Posaconazole together?
Increased irinotecan exposure and an increased irinotecan active metabolite exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Irinotecan Injection and Posaconazole interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
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.
Questions for your pharmacist
- Does my dose of Irinotecan Injection or Posaconazole 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 (2)
- Product Information: CAMPTOSAR(R) intravenous injection, irinotecan intravenous injection. Pharmacia & Upjohn Co (per Manufacturer), New York, NY, 2014. DailyMed
- Product Information: ONIVYDE(R) intravenous injection, irinotecan liposome intravenous injection. Ipsen Biopharmaceuticals Inc (per FDA), Cambridge, MA, 2024. DailyMed
Keep reading about Posaconazole
Keep reading about Irinotecan Injection
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