Which supplements should not be taken with amlodipine?

October 10, 2025 •

3 min read

According to the National Institutes of Health, untreated high blood pressure can cause significant damage to the heart, kidneys, and other vital organs. For those managing this condition with amlodipine, understanding which supplements should not be taken with amlodipine is critical to maintaining treatment effectiveness and safety.

Quick Summary

Taking amlodipine with certain supplements and foods can be dangerous. Herbal products like St. John's wort, ginkgo biloba, and ginseng, along with grapefruit and high doses of fish oil or minerals, can alter amlodipine's effectiveness or increase side effects. Always consult a healthcare provider before combining amlodipine with any supplement to avoid serious health risks.

Key Points

Avoid St. John's Wort: This herbal supplement can significantly reduce the effectiveness of amlodipine.
Do not consume grapefruit or pomegranate: These fruits can dramatically increase amlodipine levels, raising the risk of side effects.
Use caution with high-dose fish oil: High doses can lead to dangerously low blood pressure when combined with amlodipine.
Be mindful of high-dose calcium and magnesium: Both can impact amlodipine and potentially lead to excessively low blood pressure.
Consult a healthcare provider: Always discuss any supplements with your doctor or pharmacist to avoid harmful interactions.
Monitor for side effects: Watch for new or worsened symptoms when starting a new supplement.

Amlodipine is a calcium channel blocker widely prescribed to treat high blood pressure and certain heart conditions. While many supplements are considered harmless, several can interfere with amlodipine's effectiveness or increase the risk of adverse side effects. Patients must consult their healthcare provider before introducing any new supplements into their regimen.

Herbal Supplements That Interact with Amlodipine

Herbal remedies are not regulated like prescription drugs, which means their potency and potential interactions are often not fully understood. Several popular herbs have been shown to have moderate to significant interactions with amlodipine.

St. John's Wort

This herbal supplement, often used for depression, is a concern when combined with amlodipine. St. John's wort can increase the activity of a liver enzyme that breaks down amlodipine, potentially lowering the drug's concentration in the blood and reducing its effectiveness.

Ginkgo Biloba and Ginseng

Ginkgo biloba and ginseng can have the opposite effect, slowing the breakdown of amlodipine. This can lead to higher levels of amlodipine in the body, increasing the risk of side effects like low blood pressure and dizziness. The NHS notes that combining other herbal remedies with amlodipine has not been tested for safety.

Other Supplements and Foods to Avoid

Beyond herbal remedies, several other common dietary supplements and even certain foods can negatively interact with amlodipine.

Grapefruit and Pomegranate

Grapefruit and grapefruit juice are known to interact with amlodipine. They contain compounds that inhibit the enzyme responsible for breaking down amlodipine, leading to higher levels in the blood. This can cause an exaggerated blood pressure-lowering effect and an increased risk of side effects. Pomegranate juice may have similar effects and should also be avoided.

High-Dose Fish Oil

High doses of fish oil supplements can lower blood pressure. When taken with amlodipine, this can lead to dangerously low blood pressure (hypotension). It is important to discuss appropriate fish oil dosage with your doctor.

Calcium and Magnesium Supplements

High doses of calcium and magnesium supplements can also pose risks when combined with amlodipine. High-dose calcium might interfere with how amlodipine works, while high-dose magnesium, which can also lower blood pressure, could lead to an excessive drop in blood pressure. Magnesium sulfate has a known moderate interaction with amlodipine.

Supplement Interaction Comparison Table

To help visualize these potential interactions, the following table summarizes the key supplements and their effects when taken with amlodipine.


Supplement/Food	Type of Interaction	Effect on Amlodipine Levels	Risk Factors & Considerations
St. John's Wort	Enzyme Induction	Decreased	Reduced blood pressure control.
Grapefruit/Pomegranate	Enzyme Inhibition	Increased	Increased risk of low blood pressure, dizziness, and other side effects.
Ginkgo Biloba/Ginseng	Enzyme Inhibition	Increased	Increased risk of amlodipine side effects.
High-Dose Fish Oil	Additive Effect	Not applicable	Increased risk of excessively low blood pressure.
High-Dose Calcium	Potential Interference	Decreased or No effect	Can impact amlodipine's effectiveness; monitoring needed.
High-Dose Magnesium	Additive Effect	Not applicable	Exaggerated blood pressure-lowering effect.

Practicing Safe Supplementation with Amlodipine

Since many interactions involve the same liver enzyme pathway (CYP3A4), it is safest to assume that any supplement affecting liver metabolism could pose a risk. Here are some general guidelines for safe supplementation:

Always disclose everything: Inform your doctor or pharmacist about all medications, vitamins, herbs, and supplements you take before starting amlodipine.
Prioritize professional advice: Do not rely solely on online information. A healthcare professional can provide personalized advice.
Mind the dosage: High doses of supplements like fish oil, calcium, and magnesium are of particular concern. Always follow your doctor's recommendations.
Observe new symptoms: Be vigilant for any new or worsened side effects, such as increased dizziness or swelling, when starting a new supplement.

Conclusion

Managing blood pressure with amlodipine requires attention to potential interactions with other substances, including supplements and foods. Avoiding grapefruit, St. John's wort, and other interacting substances is crucial for the medication's effectiveness and to prevent dangerous side effects. Your healthcare provider is the best resource for guidance on safe supplementation while taking amlodipine.

For more detailed information on medications and health topics, reliable resources like the National Institutes of Health are invaluable.

Reliable Resource: NIH MedlinePlus on Amlodipine

Frequently Asked Questions

You should discuss this with your doctor. While some magnesium forms may not interact significantly, high doses can add to amlodipine's blood pressure-lowering effect, increasing the risk of low blood pressure.

Drinking grapefruit juice can increase the concentration of amlodipine in your body by inhibiting the enzymes that break it down. This can heighten the risk of side effects like dizziness, flushing, and dangerously low blood pressure.

Yes, St. John's wort can interact with amlodipine. It is known to speed up the metabolism of amlodipine, potentially reducing the drug's effectiveness and your blood pressure control.

Using multivitamins with minerals could decrease the effects of amlodipine. It is important to talk with your doctor before taking them together, as you may need more frequent blood pressure monitoring.

High doses of fish oil can lower blood pressure. Taking high doses with amlodipine could result in an excessive drop in blood pressure, leading to hypotension.

Yes, it is best to avoid pomegranate juice. It can inhibit the same enzymes as grapefruit juice, which can increase amlodipine levels and the risk of side effects.

For typical supplement doses, the risk is generally low, but high-dose calcium might interfere with amlodipine's action. It is wise to separate the intake times or consult your doctor for monitoring.