Pentostatin Injection and Nelarabine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 9, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Pentostatin Injection
Nelarabine
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
Reduced conversion of nelarabine to its active moiety, resulting in decreased nelarabine efficacy
Interaction Deep Dive
Pentostatin has been shown to be a strong inhibitor of adenosine deaminase (ADA) in vitro. Concurrent administration of nelarabine and pentostatin may result in reduced ADA-dependent conversion of nelarabine to its active moiety, thereby potentially decreasing nelarabine efficacy and/or altering nelarabine adverse event profile. Therefore, concomitant administration of nelarabine and pentostatin is not recommended1.
Why it happens (mechanism)
Potential inhibition of adenosine deaminase
Common questions
Can I take Pentostatin Injection and Nelarabine together?
Reduced conversion of nelarabine to its active moiety, resulting in decreased nelarabine efficacy Always confirm with your pharmacist or prescriber before making any change.
How serious is the Pentostatin Injection and Nelarabine interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
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 Pentostatin Injection or Nelarabine 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: ARRANON(R) IV injection, nelarabine IV injection. GlaxoSmithKline, Research Triangle Park, NC, 2006.
Keep reading about Pentostatin Injection
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