Drug Interaction Report

Nifedipine and Amprenavir: Interaction Details

A pharmacist-reviewed analysis of the Nifedipine and Amprenavir interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Amprenavir

No brand names on record
+

Nifedipine

Adalat® Adalat® CC Afeditab CR Afeditab® CR Nifedical® XL Nifeditab® CR Procardia Procardia®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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.

Of 325 documented Nifedipine interactions, 266 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
delayed
Evidence
theoretical
Severity
Major

What happens

Increased NIFEdipine exposure and reduced NIFEdipine exposure

Interaction Deep Dive

Avoid coadministration of NIFEdipine (CYP3A4 substrate) and amprenavir or fosamprenavir (prodrug of amprenavir) (CYP3A4 inducer) as it may significantly reduce NIFEdipine exposure. Consider alternate antihypertensive treatment32. Monitor for reduced effectiveness of NIFEdipine or for clinical signs of NIFEdipine toxicity, including hypotension and bradycardia 1. Coadministration of NIFEdipine and amprenavir or fosamprenavir, a CYP3A4 inhibitor may also increase NIFEdipine exposure. Adjust dose and consider initiating NIFEdipine at the lowest dose available if given concomitantly with NIFEdipine and amprenavir or fosamprenavir 32.

Why it happens (mechanism)

Inhibition of CYP3A4-mediated metabolism of NIFEdipine; induction of CYP3A4-mediated metabolism of NIFEdipine

Common questions

Can I take Nifedipine and Amprenavir together?

Increased NIFEdipine exposure and reduced NIFEdipine exposure Always confirm with your pharmacist or prescriber before making any change.

How serious is the Nifedipine and Amprenavir interaction?

It is rated major. Potentially serious — often needs a change or close 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

  • Does my dose of Nifedipine 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 (3)

  1. Product Information: PROCARDIA(R) oral capsules, nifedipine oral capsules. Pfizer Labs (per FDA), New York, NY, 2013. DailyMed
  2. Product Information: NIFEDIPINE oral tablet, extended-release, nifedipine oral tablet, extended-release. Aurobindo Pharma Limited (per DailyMed), East Windsor, NJ, 2024. DailyMed
  3. Product Information: PROCARDIA XL(R) oral extended-release tablets, nifedipine oral extended-release tablets. Pfizer Labs (per Dailymed), New York, NY, 2023. DailyMed
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Amprenavir

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All Amprenavir interactions (79)
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Nifedipine

Keep reading about Nifedipine

All Nifedipine interactions (325) Nifedipine drug information
Also serious with: Rifabutin Primidone Rifapentine Rifampin
Beyond drug–drug

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:

Amprenavir + Activated Charcoal Grapefruit St. John's Wort Acacia Rigidula Adrafinil African Wild Potato American Elder Astaxanthin + 141 more
Nifedipine + Activated Charcoal American Hellebore American Mistletoe Beer Coca Coleus Grapefruit Siberian Cocklebur + 265 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.