Amlodipine warnings: what you need to know

Amlodipine is an antihypertensive drug—in other words, a medicine to help lower blood pressure. It belongs to a class of medications known as calcium channel blockers (CCB), which open your blood vessels, lowering your blood pressure, and easing the strain on your heart. However, like many other drugs, it comes with warnings and potential side effects.

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Anyone with an allergic reaction to amlodipine, like hives or trouble breathing, should not use this medication. 

Certain groups of people should be warned about using amlodipine and may need to avoid using this drug or use it with caution because of the risk of adverse effects. 

People with severe coronary artery disease—more about that later—may experience worsening chest pain or even suffer a heart attack. Scientists don't know why this happens, especially since amlodipine is used to treat people with chest pain from heart disease. However, it is most likely to occur when you first start taking the drug or after you increase your dose (DailyMed, 2008). 

If you already have low blood pressure, taking a blood pressure medication like amlodipine can further lower your blood pressure, leading to fainting, dizziness, lightheadedness, etc. 

People with aortic stenosis, a narrowing of the valve connecting the aorta to the heart, should be careful with amlodipine because it may decrease the blood flow in the arteries that feed the heart (UpToDate, n.d.). 

You may want to use amlodipine with caution if you have a heart problem called obstructive hypertrophic cardiomyopathy (HCM); this causes thicker-than-normal heart walls. Amlodipine can worsen symptoms associated with this medical condition. Interestingly, people with heart failure are usually instructed to avoid calcium channel blockers; however, they can use amlodipine when directed by their healthcare provider (UpToDate, n.d.).

Lastly, amlodipine is considered FDA Pregnancy Category C—this means that there is not enough information to determine the pregnancy risk. Women and their healthcare providers should weigh the risks and benefits of the medication.

Clinical trials involving more than 11,000 people have found that amlodipine is effective and overall well-tolerated (DailyMed, 2008). 

Common side effects of amlodipine include (DailyMed, 2008): 

• Headache

• Edema (swelling) 

• Flushing

• Tiredness 

• Sleepiness (somnolence)

• Nausea 

• Stomach pain

Serious side effects can include (MedlinePlus, 2019): 

• More severe or more frequent chest pain, especially in people with severe heart disease

• Palpitations (fast, pounding, or irregular heartbeat)

• Fainting or dizziness from low blood pressure

This list does not include all possible side effects, and others may occur. Seek medical advice from your pharmacist or healthcare provider to obtain more drug information about amlodipine and whether it's right for you.

Amlodipine besylate (brand name Norvasc) is the tablet form of this medication and is available in 2.5 mg, 5 mg, and 10 mg strengths. If you can't swallow pills, it also comes in a liquid form. Amlodipine is FDA-approved to treat the following conditions (DailyMed, 2008):

• High blood pressure (hypertension): High blood pressure affects almost half of all Americans, and most aren't even aware that they have a problem. Unfortunately, if you don't treat your hypertension, it can increase your risk of heart attacks (myocardial infarctions) and strokes, among other issues (AHA, 2017). 

• Chronic stable chest pain (angina): Chest pain is a common sign of coronary artery disease and indicates that your heart muscle is not getting enough oxygen-rich blood. Angina typically occurs when your heart is working harder, like while walking or doing other physical activity. 

• Vasospastic angina (Prinzmetal's angina): Chest pain can also be caused by spasms in the coronary arteries that decrease blood flow. Unlike the chest pain of coronary artery disease, vasospastic angina occurs more often while you are at rest.

• Coronary artery disease (CAD): Coronary artery disease (also known as coronary heart disease) is a condition in which plaque builds up along the walls of the coronary arteries, the vessels that supply the heart with blood. This plaque buildup can cause the arteries to narrow, allowing less oxygen-rich blood to reach the heart (atherosclerosis). Some people with CAD have the extent of their heart disease confirmed by a procedure called angiography. In these cases, amlodipine may decrease the risk of needing future hospitalizations or heart procedures to open up narrowed vessels (DailyMed, 2008).

Before starting amlodipine, let your healthcare professional know about any other prescription drugs or over-the-counter medicines you may be taking. Some medications may have drug interactions with amlodipine. Examples include diltiazem and drugs that block the CYP3A4 enzyme in the liver, including ketoconazole, itraconazole, and ritonavir.

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Current version

May 12, 2021

Written by

Michael Martin

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.