Atorvastatin and Amprenavir: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Jul 15, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Atorvastatin
Amprenavir
No brand names on record
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
Increased atorvastatin exposure and an increased risk of myopathy or rhabdomyolysis
Interaction Deep Dive
Concomitant use of amprenavir or fosamprenavir (prodrug of amprenavir) and atorvastatin resulted in significant increases in atorvastatin Cmax and AUC values. Amprenavir, the active metabolite of fosamprenavir, both inhibits and is metabolized by the CYP3A4 isoenzyme. The CYP3A4 isoform also mediates atorvastatin metabolism. As a result, fosamprenavir competitively inhibits atorvastatin metabolism, thereby increasing the risk of atorvastatin toxicity2. Therefore, use caution with the concomitant use of atorvastatin with fosamprenavir (with or without ritonavir) and evaluate the benefits and risks of concomitant use 1. If coadministered, use the lowest atorvastatin dose necessary, titrate carefully, and do not exceed doses of 20 mg daily 2. Monitor the patient for signs and symptoms of myopathy or rhabdomyolysis (muscle pain, tenderness, or weakness), particularly during the initial months of therapy and during upward dosage titration of either drug 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of atorvastatin
Literature reports
1 report — tap to read
a) In a pharmacokinetic study (n=16), concomitant use of fosamprenavir and atorvastatin significantly increased the Cmax and AUC of atorvastatin. When fosamprenavir 1400 mg twice daily for 2 weeks was coadministered with atorvastatin 10 mg once daily for 4 days, the Cmax and AUC of atorvastatin were increased by 304% (90% CI, 205% to 437%) and 130% (90% CI, 100% to 164%), respectively. The Cmax and AUC of amprenavir were decreased by 18% (90% CI, -34% to 1%) and 27% (90% CI, -41% to -12%), respectively. When fosamprenavir 700 mg twice daily plus ritonavir 100 mg twice daily for 2 weeks were coadministered with atorvastatin 10 mg once daily for 4 days, the Cmax and AUC of atorvastatin were increased by 184% (90% CI, 126% to 257%) and 153% (90% CI, 115% to 199%), respectively. The Cmax and AUC of amprenavir did not change (increased or decreased less than or equal to 10%) 2.
Common questions
Can I take Atorvastatin and Amprenavir together?
Increased atorvastatin exposure and an increased risk of myopathy or rhabdomyolysis Always confirm with your pharmacist or prescriber before making any change.
How serious is the Atorvastatin 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 "established". Well documented — supported by controlled studies or strong clinical data.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Atorvastatin 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 (2)
- Product Information: LIPITOR(R) oral tablets, atorvastatin calcium oral tablets. Viatris Specialty LLC (per FDA), Morgantown, WV, 2022. DailyMed
- Product Information: LEXIVA(R) oral tablets, oral suspension, fosamprenavir calcium oral tablets, oral suspension. ViiV Healthcare and Vertex Pharmaceuticals Incorporated (per FDA), Research Triangle Park, NC, 2012. DailyMed
Keep reading about Atorvastatin
Keep reading about Amprenavir
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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:
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