Interferon Alfa-2B Injection and Ribavirin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ribavirin
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
Worsening mental depression, anger, and hostility
Interaction Deep Dive
In a prospective study, patients treated concurrently with interferon alfa-2b and ribavirin experienced significant increases in the severity of neuropsychiatric symptoms (depression, anxiety, anger and hostility) compared with patients treated with interferon alfa monotherapy. The incidence of neuropsychiatric disorder did not differ between treatment groups1.
Why it happens (mechanism)
Unknown
Literature reports
1 report — tap to read
a) The severity of neuropsychiatric symptoms (depression, anxiety, anger and hostility) increased in patients when interferon alfa-2b and ribavirin were concurrently administered. In a prospective, open-label, nonrandomized study, patients receiving treatment for chronic hepatitis C were given 3 to 5 million units of interferon alfa-2b 3 times weekly for up to 12 months with (n=40) or without ribavirin 1000 to 1200 milligrams daily. Psychiatric health was assessed with the Hospital Anxiety and Depression Scale (HADS) and the Symptom Checklist-90, revised (SC90R); such assessments were completed in a serial manner after 4 weeks, 3 to 4 months, 6 to 8 months, and after termination of therapy. Whereas the treatment group as a whole showed a significant increase in depression scores compared with pretreatment levels, patients receiving combination therapy scored significantly higher on the HADS depression and anxiety scales (p=0.005 and 0.032, respectively) compared with patients receiving interferon monotherapy; similar increases in anger and hostility scores were seen in patients receiving co-treatment with interferon alfa-2b and ribavirin compared with interferon monotherapy (p=0.044). The incidence rates for depression, anxiety, and anger/hostility returned to pretreatment levels after the completion of therapy 1.
Common questions
Can I take Interferon Alfa-2B Injection and Ribavirin together?
Worsening mental depression, anger, and hostility Always confirm with your pharmacist or prescriber before making any change.
How serious is the Interferon Alfa-2B Injection and Ribavirin interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
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 Interferon Alfa-2B Injection or Ribavirin 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 anything you'd monitor while I'm on both?
References (1)
- Kraus MR, Schafer A, Faller H, et al: Psychiatric symptoms in patients with chronic hepatitis C receiving interferon alfa-2b therapy. J Clin Psychiatry 2003; 64:708-714. PubMed
Keep reading about Ribavirin
Keep reading about Interferon Alfa-2B Injection
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