Drug Interaction Report

Fosamprenavir and Lovastatin: Interaction Details

A pharmacist-reviewed analysis of the Fosamprenavir and Lovastatin 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

Fosamprenavir

Lexiva
+

Lovastatin

Altocor® Altoprev Altoprev® Mevacor®
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
Contraindicated
These should generally not be used together.
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 75 documented Fosamprenavir interactions, 8 are rated contraindicated — 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
Contraindicated

What happens

An increased risk of myopathy or rhabdomyolysis

Interaction Deep Dive

Due to the potential for serious reactions, such as risk of myopathy and rhabdomyolysis, concomitant therapy with fosamprenavir and lovastatin is contraindicated1. Fosamprenavir is metabolized by CYP3A4. The CYP3A4 enzymes are also involved in lovastatin metabolism. As a result, fosamprenavir may competitively inhibit lovastatin metabolism, thereby increasing the risk of myopathy and rhabdomyolysis 2.

Why it happens (mechanism)

Inhibition of CYP3A4-mediated lovastatin metabolism

Common questions

Can I take Fosamprenavir and Lovastatin together?

An increased risk of myopathy or rhabdomyolysis Always confirm with your pharmacist or prescriber before making any change.

How serious is the Fosamprenavir and Lovastatin interaction?

It is rated contraindicated. These should generally not be used together.

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 Fosamprenavir or Lovastatin 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 (2)

  1. Product Information: LEXIVA(R) oral tablets, suspension, fosamprenavir oral tablets, suspension. GlaxoSmithKline, Research Triangle Park, NC, 2007. DailyMed
  2. Product Information: Mevacor(R), lovastatin. Merck & Co. Inc. Whitehouse Station, NJ, 2002. DailyMed
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Fosamprenavir

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Lovastatin

Keep reading about Lovastatin

All Lovastatin interactions (127) Lovastatin drug information
Also serious with: Clarithromycin Ceritinib Atazanavir Boceprevir
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:

Fosamprenavir + Activated Charcoal Grapefruit St. John's Wort Acacia Rigidula Adrafinil African Wild Potato American Elder Astaxanthin + 135 more
Lovastatin + Activated Charcoal Apple Beer Grapefruit Siberian Cocklebur St. John's Wort Sweet Orange Wine + 176 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.