Palbociclib and Atorvastatin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Jul 15, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Atorvastatin
Palbociclib
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
Interaction Deep Dive
One fatal case of suspected statin-induced rhabdomyolysis associated with concomitant atorvastatin and palbociclib use has been reported. Inhibition of CYP3A4-mediated atorvastatin metabolism by palbociclib has been proposed as a possible mechanism for this interaction2. Palbociclib is a weak inhibitor of CYP3A. Coadministration of palbociclib and midazolam, a sensitive CYP3A substrate, increased midazolam AUC by 61% in healthy volunteers 1. Monitor AST/ALT and creatine kinase if atorvastatin, a CYP3A4 substrate, and palbociclib are prescribed together 2.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of atorvastatin by palbociclib
Literature reports
2 reports — tap to read
a) Concomitant use of atorvastatin, a CYP3A4 substrate, and palbociclib was associated with a fatal case of rhabdomyolysis. A 60- to 65-year old female patient who had received chronic atorvastatin 40 mg initiated treatment with fulvestrant and palbociclib for metastatic breast cancer. After receiving fulvestrant and 2 cycles of palbociclib, she presented with progressive proximal muscle weakness. Upon hospitalization, all 3 medications were discontinued, but her condition worsened and she died 8 days later. Laboratory findings on presentation included elevated creatine kinase (CK; 14,572 units/L), AST/ALT (1276/691 units/L), aldolase (59.1 units/L), and lactate dehydrogenase (1752 units/L). An antibody panel for myositis and myopathy was negative. Pathologic findings indicated a toxic or metabolic etiology of muscle damage. The authors hypothesize that adding palbociclib to atorvastatin may have resulted in inhibition of CYP3A4-mediated metabolism of atorvastatin and a clinically significant increase of atorvastatin concentration precipitating statin-induced rhabdomyolysis or that there was additive or symbiotic toxicity. They recommend the monitoring of creatine kinase and AST/ALT when statins and palbociclib are prescribed concomitantly 2.
b) Palbociclib is a weak inhibitor of CYP3A. The coadministration of midazolam, a sensitive CYP3A substrate, and multiple daily doses of palbociclib resulted in a 61% increase in midazolam AUC and a 37% increase in midazolam Cmax compared with midazolam alone in a drug interaction study in healthy volunteers (N=26) 1.
Common questions
Can I take Palbociclib and Atorvastatin together?
Increased atorvastatin exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Palbociclib and Atorvastatin 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 "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Palbociclib or Atorvastatin 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)
Keep reading about Atorvastatin
Keep reading about Palbociclib
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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