Irinotecan Injection and Apalutamide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Apalutamide
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
Reduced irinotecan exposure and reduced irinotecan active metabolite exposure
Interaction Deep Dive
Avoid coadministration of irinotecan or irinotecan liposome with apalutamide (strong CYP3A4 inducer) unless there are no alternative therapies, as exposure of irinotecan or its active metabolite, SN-38 may be reduced. Use alternative nonenzyme-inducing therapy beginning at least 2 weeks prior to initiation of irinotecan therapy21. Concomitant use of apalutamide with irinotecan or irinotecan liposome (OATP1B1/BCRP and CYP3A4 substrate) may reduce the efficacy of irinotecan or irinotecan liposome. Evaluate for loss of activity of the substrate if concomitant use cannot be avoided 4.
Why it happens (mechanism)
Induction of OATP1B1-mediated efflux transport of irinotecan; induction of BCRP-mediated efflux transport of irinotecan; induction of CYP3A4-mediated metabolism of irinotecan
Literature reports
3 reports — tap to read
a) In a systematic review of studies of pharmacokinetic interactions involving St John's Wort, concomitant use with irinotecan in 1 study (N=5) resulted in a decrease in irinotecan AUC of 42% with a St. John's Wort dosage of 300 mg 3 times daily (hyperforin dose not known) 3.
b) Coadministration of apalutamide with single oral doses of transporter substrates resulted in a 41% decrease in the AUC of rosuvastatin (BCRP/OATP1B1 substrate) 4.
c) Coadministration of a single dose of apalutamide with midazolam, CYP3A4 substrate, resulted in a 92% decrease in the midazolam AUC 4.
Common questions
Can I take Irinotecan Injection and Apalutamide together?
Reduced irinotecan exposure and reduced irinotecan active metabolite exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Irinotecan Injection and Apalutamide 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 Apalutamide 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 (4)
- 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
- Chrubasik-Hausmann S, Vlachojannis J, & McLachlan AJ: Understanding drug interactions with St John's wort (Hypericum perforatum L.): impact of hyperforin content. J Pharm Pharmacol 2019; 71(1):129-138.
- Product Information: ERLEADA® oral tablets, apalutamide oral tablets. Janssen Products LP (per FDA), Horsham, PA, 2026. DailyMed
Keep reading about Apalutamide
Keep reading about Irinotecan Injection
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