Midazolam Injection and Amprenavir: 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 recordMidazolam 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
An increased risk of midazolam toxicity (excessive sedation, confusion)
Interaction Deep Dive
Because of the potential for serious and/or life-threatening prolonged sedation that can occur with increased plasma concentrations of midazolam, the concurrent use of amprenavir and midazolam is contraindicated. Currently no interaction study has been conducted. Amprenavir and midazolam are both metabolized by cytochrome P450 3A4 enzymes, and the competition for metabolism could result in an increased plasma concentration of midazolam1.
Why it happens (mechanism)
Competitive inhibition of cytochrome P450 3A4-mediated midazolam metabolism
Common questions
Can I take Midazolam Injection and Amprenavir together?
An increased risk of midazolam toxicity (excessive sedation, confusion) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Midazolam Injection and Amprenavir interaction?
It is rated contraindicated. These should generally not be used together.
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 "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Midazolam Injection or Amprenavir 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: Agenerase(R), amprenavir. Glaxo Wellcome Inc. Research Triangle Park, NC, 2000.
Keep reading about Amprenavir
Keep reading about Midazolam 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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