Amprenavir and Dapsone: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Amprenavir
No brand names on recordDapsone
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
An increased risk of dapsone toxicity (hemolytic anemia, methemoglobinemia, lethargy, weakness)
Interaction Deep Dive
Amprenavir is metabolized by cytochrome P450 3A4 isoenzymes in addition to inhibiting CYP3A41. It is possible that concurrent use of dapsone and amprenavir could result in reduced dapsone metabolism, thereby leading to increased dapsone serum concentrations and potential dapsone toxicity.
Why it happens (mechanism)
Inhibition of cytochrome P450 3A4-mediated dapsone metabolism
Common questions
Can I take Amprenavir and Dapsone together?
An increased risk of dapsone toxicity (hemolytic anemia, methemoglobinemia, lethargy, weakness) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amprenavir and Dapsone 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 Amprenavir or Dapsone 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)
- Product Information: Agenerase(R), amprenavir. Glaxo Wellcome Inc. Research Triangle Park, NC, 2000.
Keep reading about Amprenavir
Keep reading about Dapsone
These medications also interact with supplements
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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