ModerateCaution
Both amlodipine and magnesium act as calcium channel blockers through related mechanisms, creating additive hypotensive effects. Amlodipine blocks L-type voltage-gated calcium channels pharmacologically, while magnesium is a physiological calcium antagonist. Oral magnesium supplements generally produce modest effects, but the combination warrants blood pressure monitoring. Intravenous magnesium with calcium channel blockers is contraindicated due to risk of severe hypotension and cardiac depression.
Recommendation: Oral magnesium supplementation is generally safe at moderate doses (200-350 mg/day supplemental elemental magnesium) with amlodipine, but monitor blood pressure when starting. Avoid high-dose magnesium supplements. If experiencing dizziness or lightheadedness, reduce magnesium dose. Never use IV magnesium with amlodipine without medical supervision.
ModerateCaution
Quercetin, a flavonoid found in grapefruit and many supplements, inhibits CYP3A4 and intestinal P-glycoprotein in vitro. Amlodipine is a CYP3A4 substrate. However, amlodipine has high inherent oral bioavailability (~65%), making it less susceptible to CYP3A4 inhibition than other calcium channel blockers like nifedipine or felodipine. Clinical studies show grapefruit juice increases amlodipine levels by only 15-20%, producing minimal hemodynamic changes compared to the 100%+ increases seen with felodipine.
Recommendation: Moderate intake of quercetin supplements or grapefruit is generally acceptable with amlodipine. Avoid excessive grapefruit consumption (more than 1 glass/day) or very high-dose quercetin supplements (>1000 mg/day). Monitor blood pressure if significantly increasing quercetin or grapefruit intake.
SeriousConflict
St. John's Wort is a potent inducer of CYP3A4 via pregnane X receptor (PXR) activation. Amlodipine is primarily metabolized by CYP3A4. Co-administration can significantly reduce amlodipine blood levels, potentially rendering the medication ineffective at controlling blood pressure. The induction effect typically develops over 10-14 days and takes a similar period to resolve after discontinuation.
Recommendation: Avoid combining St. John's Wort with amlodipine. If currently taking both, consult your prescriber before making changes. Abruptly stopping St. John's Wort could cause amlodipine levels to rise. If blood pressure control is lost, St. John's Wort should be considered as a potential cause.
ModerateCaution
Berberine is a clinically demonstrated inhibitor of CYP3A4, the main enzyme that clears amlodipine. Co-administration can raise amlodipine plasma levels and prolong its half-life, increasing the risk of excessive blood pressure lowering, peripheral edema, dizziness, and reflex tachycardia. The effect builds over days because berberine accumulates with repeated dosing.
Recommendation: Avoid pairing berberine with amlodipine unless your prescriber agrees, and if you do, separate doses by at least 4 hours and monitor your blood pressure for 1-2 weeks. Reduce or stop berberine if your readings fall below your usual range, or you develop new lightheadedness or swelling.
ModerateCaution
Curcumin inhibits CYP3A4 and intestinal P-glycoprotein, both of which contribute to amlodipine clearance and absorption. In a rat pharmacokinetic study, curcumin pretreatment more than doubled amlodipine AUC and Cmax, suggesting that high-dose curcumin or curcumin phytosome formulations could push amlodipine levels into a range that causes hypotension, edema, or reflex tachycardia in humans.
Recommendation: If you take amlodipine, keep turmeric to culinary amounts and avoid high-dose curcumin supplements unless your prescriber agrees. If you do use a curcumin product, separate it from amlodipine by at least 4 hours, check blood pressure for 1-2 weeks, and stop if you develop new dizziness or swelling.
ModerateCaution
Curcumin phytosome formulations achieve 20-30 times higher plasma curcumin levels than standard curcumin, which magnifies any CYP3A4-mediated drug interaction. Because amlodipine is cleared almost entirely by CYP3A4, even modest enzyme inhibition can produce clinically meaningful increases in drug exposure, with hypotension, peripheral edema, or reflex tachycardia.
Recommendation: Avoid pairing curcumin phytosome products with amlodipine. If your clinician approves their use, separate doses by at least 4 hours, monitor blood pressure for 2 weeks, and stop or reduce the dose if readings drop below your usual range or you develop new swelling.
ModerateCaution
L-Arginine is a nitric oxide precursor that lowers systolic and diastolic blood pressure by about 5/3 mmHg in meta-analysis. Combined with amlodipine's dihydropyridine vasodilation, the additive effect can produce symptomatic hypotension, dizziness, or reflex tachycardia, especially in patients already at goal blood pressure.
Recommendation: If you take amlodipine, start L-arginine at low doses (1-3 g/day) and monitor your blood pressure before and after starting. Reduce or stop if you develop dizziness, headache, or readings below your usual range, and inform your prescriber.
ModerateCaution
L-Citrulline is converted to L-arginine and raises plasma arginine more efficiently than oral arginine itself, producing nitric-oxide-mediated vasodilation. Stacked on top of amlodipine's calcium channel blockade, this can drop blood pressure further than intended, with dizziness, fatigue, or headache.
Recommendation: If you take amlodipine, start L-citrulline at lower doses (3 g/day or less) and track blood pressure for 1-2 weeks. Reduce the dose or stop if you become lightheaded or your readings fall below your usual range.
InfoSynergy
Omega-3 fatty acids in fish oil produce small but consistent reductions in blood pressure (about 2-3 mmHg systolic at doses of 2-3 g/day) and lower triglycerides, complementing amlodipine's antihypertensive effect. The combination is generally beneficial in patients with hypertension or cardiovascular disease.
Recommendation: Fish oil at 1-3 g/day combined with amlodipine is appropriate for most patients with cardiovascular risk. Monitor blood pressure when starting, and tell your prescriber if you use high doses (>3 g/day) since the hemodynamic effect can become additive.
ModerateCaution
Aged garlic extract reduces systolic and diastolic blood pressure by about 8 and 5 mmHg in hypertensive patients in meta-analysis. Added on top of amlodipine, the additive antihypertensive effect can be welcome but can also produce dizziness or symptomatic hypotension in patients already at goal blood pressure.
Recommendation: If you take amlodipine, monitor your blood pressure for 2-4 weeks after starting garlic extract. If readings drop below your usual range or you become lightheaded, reduce the garlic dose or talk with your prescriber about lowering amlodipine.
InfoSynergy
CoQ10 produces a small but consistent reduction in systolic blood pressure (about 3-5 mmHg) and improves endothelial function, complementing amlodipine's antihypertensive effect. The combination is generally beneficial and well-tolerated, especially in patients with metabolic syndrome or coexisting heart failure.
Recommendation: CoQ10 at 100-200 mg/day combined with amlodipine is appropriate for most patients with hypertension or cardiometabolic disease. Monitor blood pressure for 4 weeks after starting, and adjust amlodipine with your prescriber if readings fall consistently below your goal.
InfoSynergy
Ubiquinol is the reduced, more bioavailable form of CoQ10 and produces the same modest blood-pressure-lowering and endothelial benefits as ubiquinone, often at lower doses. Combined with amlodipine, the additive systolic-pressure reduction is usually beneficial but can occasionally drop blood pressure further than intended in well-controlled patients.
Recommendation: Ubiquinol at 50-100 mg/day combined with amlodipine is appropriate for most patients with hypertension or cardiometabolic disease. Monitor blood pressure for 4 weeks after starting and adjust amlodipine with your prescriber if readings drop below your goal.
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