Paclitaxel Protein-Bound and Simvastatin: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 4, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Simvastatin
Paclitaxel Protein-Bound
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.
You've been prescribed two medicines that both use the same liver pathway (an enzyme called CYP3A4). Simvastatin is a cholesterol drug, and paclitaxel is a chemotherapy medicine. Because they share this pathway, the amount of paclitaxel in your body could shift, which in theory might change how well it works or raise the chance of chemo side effects like low blood counts, numbness or tingling in the hands and feet, or fatigue.
The good news is this is a theoretical concern, not something proven to happen every time. Your cancer and pharmacy team know how to watch for this. Keep taking both exactly as prescribed, and let them know about all your medicines so they can monitor you closely.
Mechanism: Paclitaxel is metabolized partly via CYP3A4 (to 3'-p-hydroxypaclitaxel and 6-alpha,3'-p-dihydroxypaclitaxel). Co-administration with CYP3A4 substrates such as simvastatin may alter paclitaxel exposure. Neither drug is a prodrug requiring activation, so the concern is shifted paclitaxel PK rather than lost activation.
- Direction: Altered (potentially reduced efficacy or increased toxicity) paclitaxel exposure.
- Onset: Delayed.
- Evidence: Theoretical, based largely on in vitro data.
- Management: Exercise caution; monitor for paclitaxel toxicity (myelosuppression, peripheral neuropathy). Doses may be individualized and closer monitoring applied by the oncology team.
What happens
Altered (increased/reduced) PACLitaxel exposure, reduced PACLitaxel exposure and an increased PACLitaxel-related adverse reactions and toxicity
Interaction Deep Dive
Use caution when PACLitaxel is given together with CYP3A4 substrates12, [and this applies to PACLitaxel protein-bound particles for injectable suspension (albumin-bound)] when combined with agents identified as CYP3A4 substrates, since such concurrent use can change PACLitaxel exposure 3. According to in vitro studies, CYP3A4 metabolized PACLitaxel mainly into 2 minor metabolites, namely 3'-p-hydroxyPACLitaxel and 6-alpha, 3'-p-dihydroxyPACLitaxel. In vivo interactions with compounds that serve as CYP3A4 substrates may likewise modify the pharmacokinetics of PACLitaxel 13.
Why it happens (mechanism)
Inhibition of CYP3A4-substrates metabolism by PACLitaxel; induction of CYP3A4-substrates metabolism by PACLitaxel
How to manage this interaction
This interaction is theoretical, so your care team can usually manage it without stopping either medicine.
- Keep taking both exactly as prescribed unless your oncologist tells you otherwise.
- Your team may monitor you more closely for chemotherapy side effects such as low blood counts, infections, unusual bruising, or numbness and tingling in your hands and feet.
- Your paclitaxel dose may be adjusted and individualized by your oncology team if needed.
- Make sure your pharmacist and prescriber have your full medication list, and report any new or worsening symptoms right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In vitro investigations demonstrated that PACLitaxel was converted mainly into 2 minor metabolites, 3'-p-hydroxyPACLitaxel and 6-alpha, 3'-p-dihydroxyPACLitaxel, through CYP3A4. The pharmacokinetics of PACLitaxel might likewise be modified because of in vivo interactions with agents that serve as substrates of CYP3A4 13.
Common questions
Can I take Paclitaxel Protein-Bound and Simvastatin together?
Simvastatin and paclitaxel both use the CYP3A4 liver pathway, so paclitaxel levels could shift in theory. Keep taking both as prescribed and let your oncology team monitor you for chemo side effects. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Paclitaxel Protein-Bound and Simvastatin interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How is the Paclitaxel Protein-Bound and Simvastatin interaction managed?
This interaction is theoretical, so your care team can usually manage it without stopping either medicine. Keep taking both exactly as prescribed unless your oncologist tells you otherwise. Your team may monitor you more closely for chemotherapy side effects such as low blood counts, infections, unusual bruising, or numbness and tingling in your hands and feet. Your paclitaxel dose may be adjusted… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Paclitaxel Protein-Bound or Simvastatin 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 anything you'd monitor while I'm on both?
References (3)
- Product Information: PACLITAXEL intravenous injection, paclitaxel intravenous injection. Fresenius Kabi (per Dailymed), Lake Zurich, IL, 2024. DailyMed
- Product Information: TAXOL(R) IV injection, paclitaxel IV injection. Bristol-Myers Squibb Company, Princeton, NJ, 2011.
- Product Information: PACLITAXEL PROTEIN-BOUND PARTICLES (ALBUMIN-BOUND) intravenous injection lyophilized powder for suspension, paclitaxel protein-bound particles (albumin-bound) intravenous injection lyophilized powder for suspension. Sandoz Inc (per Dailymed), Princeton, NJ, 2024. DailyMed
Keep reading about Simvastatin
Keep reading about Paclitaxel Protein-Bound
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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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