Interferon Alfa-2B Injection and Clozapine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Clozapine
Interferon Alfa-2B 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 clozapine exposure
Interaction Deep Dive
The concomitant use of clozapine (a CYP1A2 substrate) with this drug (a weak or moderate CYP1A2 inhibitor) may increase the exposure of clozapine and lead to an increase in adverse events. If used concomitantly, monitor for adverse events and consider reducing the clozapine dose as necessary. If the inhibitor is discontinued, monitor closely for lack of clozapine effectiveness and consider increasing the dose as necessary1.
Why it happens (mechanism)
Inhibition of CYP1A2-mediated metabolism of clozapine
Common questions
Can I take Interferon Alfa-2B Injection and Clozapine together?
Increased clozapine exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Interferon Alfa-2B Injection and Clozapine 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 Interferon Alfa-2B Injection or Clozapine 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: CLOZARIL(R) oral tablets, clozapine oral tablets. HLS Therapeutics USA Inc (per FDA), Rosemont, PA, 2020. DailyMed
Keep reading about Clozapine
Keep reading about Interferon Alfa-2B Injection
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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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