What not to mix with amLODIPine?

October 6, 2025 •

4 min read

Over 2 million prescriptions for amlodipine were dispensed in 2021, making it one of the most common medications in the United States. For those relying on this vital medication, understanding what not to mix with amlodipine is critical for both its effectiveness and safety.

Quick Summary

This guide outlines specific medications, foods, and supplements that can cause dangerous interactions with amlodipine. Highlighting the mechanisms behind these interactions, it provides crucial information on what to avoid to prevent severe side effects like dangerously low blood pressure and muscle damage.

Key Points

Avoid grapefruit products: Grapefruit and its juice can increase amlodipine concentration in the bloodstream, raising the risk of hypotension and other side effects.
Use caution with alcohol: Alcohol can increase amlodipine's side effects like dizziness and low blood pressure, so use it sparingly or avoid it entirely.
Discuss simvastatin with your doctor: When taking amlodipine with simvastatin, there is an increased risk of muscle damage, and your doctor will advise on appropriate management.
Be aware of certain antibiotics and antifungals: Medications like clarithromycin, erythromycin, and ketoconazole can increase amlodipine levels and cause low blood pressure.
Inform your doctor about supplements: Herbal remedies like St. John's wort can decrease amlodipine's effectiveness, so always disclose supplement use to your healthcare provider.
Monitor blood pressure with other antihypertensives: Combining amlodipine with other blood pressure medications or ED drugs like sildenafil can cause dangerously low blood pressure.

Understanding the importance of drug interactions

Medication interactions occur when one substance alters the effect of another, potentially making it more potent or less effective, or causing new side effects. As a calcium channel blocker, amlodipine works by relaxing blood vessels to lower blood pressure and is often prescribed for hypertension and angina. However, its metabolism in the liver via the CYP3A4 enzyme makes it susceptible to numerous interactions. Being vigilant about these combinations is essential for safe and effective treatment. Always consult a healthcare provider before combining amlodipine with other substances.

Medications with major amlodipine interactions

Certain medications can significantly affect amlodipine levels in your body, leading to either an increased risk of side effects or a reduced therapeutic effect. Healthcare providers often need to adjust dosages or avoid these combinations entirely.

Medications that increase amlodipine levels

These drugs inhibit the CYP3A4 enzyme, leading to higher concentrations of amlodipine in the bloodstream and increasing the risk of low blood pressure (hypotension) and edema (swelling).

Certain antibiotics: Macrolide antibiotics like clarithromycin and erythromycin, especially in older adults, can dangerously increase amlodipine levels.
Azole antifungals: Ketoconazole, itraconazole, and fluconazole are known CYP3A4 inhibitors that raise amlodipine concentrations.
HIV antivirals: Ritonavir and other protease inhibitors used to treat HIV can also significantly increase amlodipine's presence in the body.
Immunosuppressants: Tacrolimus and cyclosporine can see increased levels when taken with amlodipine, potentially raising the risk of toxicity from the immunosuppressant itself.

Medications that decrease amlodipine levels

Some medications can speed up amlodipine's metabolism, reducing its effectiveness at controlling blood pressure.

Certain seizure drugs: Antiepileptic medications such as carbamazepine, phenytoin, and phenobarbital can make amlodipine less effective.
Rifampin: This antibiotic significantly lowers amlodipine concentrations in the blood.

Medications with additive effects

Combining amlodipine with other medications that also lower blood pressure can lead to an additive hypotensive effect, causing symptoms like dizziness and fainting.

Other blood pressure medications: Using amlodipine with other antihypertensives like ACE inhibitors (e.g., lisinopril), beta-blockers (e.g., metoprolol), or other calcium channel blockers requires careful monitoring.
Erectile dysfunction (ED) medications: PDE5 inhibitors like sildenafil (Viagra), tadalafil (Cialis), and avanafil can cause steep drops in blood pressure when combined with amlodipine.

Food, drink, and supplement interactions

Beyond prescription drugs, certain foods and supplements can also trigger adverse interactions with amlodipine.

Grapefruit and grapefruit juice

One of the most well-known interactions involves grapefruit and its juice. Furanocoumarins in grapefruit inhibit the CYP3A4 enzyme in the gut, which can lead to higher-than-normal levels of amlodipine in the bloodstream. This can cause an exaggerated blood pressure-lowering effect and increase the risk of side effects like flushing, headache, and ankle swelling. While some studies suggest minimal impact with small quantities, many healthcare providers recommend avoiding grapefruit products entirely while on amlodipine.

St. John's wort

This herbal supplement, often used for depression, is a known CYP3A4 inducer, meaning it can increase the activity of the enzyme. The result is a faster breakdown of amlodipine, which can render the medication less effective at managing blood pressure.

Alcohol

While not a major interaction, alcohol can exacerbate some of amlodipine's side effects. Both substances can cause dizziness, drowsiness, and a drop in blood pressure. Combining them can worsen these effects, especially for older individuals or those with underlying health conditions.

Simvastatin

Amlodipine can increase the concentration of simvastatin, a cholesterol-lowering medication (statin), in the body. This significantly increases the risk of muscle-related side effects, including myopathy and the more severe rhabdomyolysis. The FDA provides guidance regarding the combination of amlodipine and simvastatin. Alternative statins like atorvastatin or rosuvastatin may be preferred in some cases.

Comparison of amlodipine interactions


Interaction Type	Examples	Potential Effect	What to Do
Increased Amlodipine Levels	Clarithromycin, Itraconazole, Ritonavir, Grapefruit	Lower blood pressure, increased swelling, dizziness	Avoid combination; discuss alternatives with healthcare provider
Decreased Amlodipine Levels	Carbamazepine, Rifampin, St. John's wort	Reduced blood pressure control	Monitor blood pressure; discuss alternatives with healthcare provider
Additive Blood Pressure Effect	Sildenafil (Viagra), Metoprolol, Alcohol	Dangerously low blood pressure, fainting	Monitor blood pressure; use caution, especially when starting or changing medications
Increased Companion Drug Levels	Simvastatin, Tacrolimus, Cyclosporine	Increased risk of muscle damage (statins) or toxicity (immunosuppressants)	Discuss appropriate management with healthcare provider, which may include dosage adjustments or switching to an alternative drug

Conclusion

While amlodipine is a generally safe and effective medication, its broad use and metabolic pathway expose it to numerous potential interactions with other drugs, foods, and supplements. Major risks range from dangerously low blood pressure to an increased risk of severe muscle damage. By understanding what not to mix with amlodipine—including common substances like grapefruit, certain antibiotics, and statins—patients can take an active role in their treatment safety. Always maintain open communication with your healthcare team, and inform them of all medications and supplements you are taking to prevent potential complications. For more information on general drug interaction awareness, refer to resources like the U.S. Food and Drug Administration (FDA) at https://www.fda.gov/drugs/drug-interactions-what-you-should-know/ for guidance.

Frequently Asked Questions

You should exercise caution when drinking alcohol with amlodipine. Both can cause dizziness and lower blood pressure, and combining them can worsen these effects. It is best to limit or avoid alcohol consumption.

For most people, it is best to avoid grapefruit and grapefruit juice. Grapefruit can inhibit the CYP3A4 enzyme, leading to higher levels of amlodipine and increasing the risk of side effects like low blood pressure and swelling.

While amlodipine can increase levels of simvastatin and lovastatin, other statins like atorvastatin (Lipitor) or rosuvastatin (Crestor) are generally safer to use in combination because they are not primarily metabolized by the same enzyme.

This combination requires caution. Both amlodipine and sildenafil lower blood pressure, and taking them together can cause an additive effect, leading to dangerously low blood pressure. Your doctor will monitor you closely if this combination is necessary.

You should avoid taking St. John's wort, as it can reduce the effectiveness of amlodipine. Always tell your doctor about any herbal supplements you are taking, as they can have unforeseen interactions.

Yes, certain antibiotics interact with amlodipine. Macrolide antibiotics like clarithromycin can increase amlodipine levels, while rifampin can decrease them. Always inform your doctor if you start a new antibiotic.

You should check with your doctor before taking OTC cold medicines, especially those containing decongestants like pseudoephedrine. These stimulants can counteract amlodipine's blood pressure-lowering effect.