Supplements and Felodipine.
Felodipine, sold under the brand names Plendil, Cardioplen XL, Felogen XL, Felotens XL, Vascalpha, is a calcium channel blocker: it relaxes vascular smooth muscle and reduces afterload.
Felodipine is a calcium channel blocker. The dihydropyridine subclass (amlodipine, felodipine, nifedipine) preferentially blocks arterial L-type channels and is prescribed mainly for hypertension. Verapamil and diltiazem sit outside the dihydropyridine family. They also affect cardiac conduction and are used for arrhythmia control. CYP3A4 metabolism applies across the class, so 3A4 inhibitors (grapefruit, and certain supplements at higher doses including curcumin, quercetin, and schisandra) can raise plasma levels by 20 to 40 percent. The side effect most often reported is ankle oedema, from preferential arteriolar dilation, and it scales with dose. Additive BP supplements (beetroot, hibiscus, garlic, CoQ10 at the studied doses) stack on top. Verapamil and diltiazem carry an additional interaction with CoQ10. This is the only adjacent cardiac class where the CoQ10 evidence is meaningful, since they have a small negative inotropic effect that CoQ10 marginally offsets.
Below are the 2 documented pairs we have explicitly assessed against Felodipine in the Distil database: 2 amber. The pairs cluster around 2 mechanisms: Reduced blood-pressure-medicine effect and CYP3A4 inhibition. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not on this list is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by supplement, and the missing-item form at the bottom of the page routes any uncatalogued supplement into our next curation pass.
Documented interactions
Reduced blood-pressure-medicine effect
Melatonin has been shown to raise blood pressure and heart rate in people taking the related blood-pressure drug nifedipine, working against it. Felodipine is in the same drug family, so the same effect may apply. If you take felodipine, it is worth discussing melatonin with your prescriber and monitoring your blood pressure rather than starting it on your own.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
CYP3A4 inhibition
Bergamot is grapefruit-family citrus and can raise felodipine blood levels significantly. Felodipine is the textbook example of a calcium channel blocker affected by grapefruit-family citrus. Discuss with your GP before combining.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope (food-supplement interactions only; for drug-drug interactions, the BNF is authoritative). Use the checker below to surface any supplement, and submit a missing item if you take something we have not catalogued.
How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
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