What kind of interaction is it?

Caution: an interaction that may reduce efficacy or raise side-effect risk and warrants monitoring.

Is this interaction backed by published research?

Yes. NutriStack lists 1 citation row for the Felodipine + Quercetin pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Supplement × Prescription·a caution·Emerging evidence

Felodipine + Quercetin

Q: Can I take Felodipine and Quercetin together?

Possibly, but with caution. Felodipine and Quercetin have a documented caution-tier interaction. Quercetin inhibits CYP3A4 and P-glycoprotein in laboratory and some clinical studies. Because felodipine is a sensitive CYP3A4 substrate with low and variable oral bioavailability, high-dose quercetin supplements could raise felodipine concentrations and increase the risk of hypotension, flushing, headache, and peripheral edema.

Q: How does this affect a NutriStack Stack Score?

-5 to your Stack Score per scored caution row.

Caution Emerging evidence

Quercetin inhibits CYP3A4 and P-glycoprotein in laboratory and some clinical studies. Because felodipine is a sensitive CYP3A4 substrate with low and variable oral bioavailability, high-dose quercetin supplements could raise felodipine concentrations and increase the risk of hypotension, flushing, headache, and peripheral edema.

Supplement × Prescription

Open the interaction checker → Read the methodology

From the database

What the row says.

Every entry follows the same shape: what is happening, the mechanism, and the recommendation.

Substances

Felodipine and Quercetin

Pair type

Caution

Evidence

Emerging

Source citations

Scope

Supplement × Prescription

Last verified

June 4, 2026

CautionEmerging evidence

What is happening. Quercetin inhibits CYP3A4 and P-glycoprotein in laboratory and some clinical studies. Because felodipine is a sensitive CYP3A4 substrate with low and variable oral bioavailability, high-dose quercetin supplements could raise felodipine concentrations and increase the risk of hypotension, flushing, headache, and peripheral edema.

Mechanism. Quercetin inhibits intestinal and hepatic CYP3A4 and P-glycoprotein, which can reduce first-pass metabolism and efflux of felodipine and increase its systemic exposure, similar in direction to the grapefruit-felodipine interaction.

Recommendation. Avoid high-dose quercetin supplements with felodipine unless cleared by the prescriber. If used, monitor for excessive blood-pressure lowering and dihydropyridine side effects, and keep the dose modest.

Stack Score

How it moves the number.

Effect on the composite score

If both Felodipine and Quercetin are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).

The full algorithm, the clamping rules, and four worked stacks are at /methodology/stack-score.

Sources

Sources, by evidence tier.

Every claim on this page is cited. PMIDs link straight to PubMed.

Reference material

1Choi JS, Choi BC, Choi KE. Effect of quercetin on the pharmacokinetics of oral drugs that are CYP3A4 substrates. Int J Pharm. 2004.Needs sourceNo link

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