Amlodipine is an oral medication that doctors prescribe to treat some cardiovascular conditions. In the United States, it commonly goes under the brand name Norvasc.

Amlodipine is a type of calcium channel blocker. Doctors commonly prescribe these drugs to treat people with high blood pressure. A doctor may also prescribe amlodipine for coronary artery disease and angina.

In this article, we look at what doctors prescribe amlodipine for and its recommended dosage. We also cover the side effects, interactions, warnings, and considerations for amlodipine as well as some alternative drugs.

packages of Norvasc, brand name of amlodipine. image credit: Kimivanil, 2015.Share on Pinterest
Amlodipine is usually known as Norvasc in the U.S.
Image credit: Kimivanil, 2015.

The U.S. Food and Drug Administration (FDA) first approved amlodipine in 1987. The FDA consider amlodipine safe and effective for treatment of:

  • high blood pressure, which doctors refer to as hypertension
  • coronary artery disease
  • angina, which is chest pain resulting from reduced blood flow to the heart

Doctors sometimes also prescribe amlodipine to treat people with other conditions. This is known as "off-label" treatment because the FDA has not yet approved the drug for these uses.

According to one source, off-label uses of amlodipine include:

The dosage for amlodipine depends on the person's condition and how well their symptoms respond to treatment. The doctor will also take into account an individual's age and medical history when recommending a dosage.

According to the FDA's prescribing information leaflet, amlodipine is available in tablets and capsule form and in a range of strengths, including 2.5 milligrams (mg), 5mg, and 10mg quantities.

Doctors prescribe amlodipine for a variety of conditions, and the FDA recommend the following dosages:

For treating high blood pressure:

  • For adults: starting with 5 mg once daily with a maximum dose of 10 mg daily.
  • For older people or those with liver problems: 2.5mg once daily.
  • For children aged 6–17 years old: 2.5mg or 5 mg once daily.

The FDA also recommend that doctors adjust a person's dosage according to blood pressure goals, but wait between 7 and 14 days between changes.

For treating chronic stable or vasospastic angina:

  • For adults: 5 mg to 10 mg once daily. Most people will need to take 10 mg for the drug to treat their angina effectively.
  • For older people or those with liver problems: 5 mg once daily.

For treating chronic artery disease:

  • For adults: 5 to 10mg once daily.
  • For older people or those with liver problems: 5 mg once daily.

For some people who have difficulty swallowing, such as children and older people, a doctor may administer amlodipine as an intravenous injection or drip.

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Side effects of amlodipine can include drowsiness.

According to the FDA, researchers have used clinical trials to evaluate the safety of amlodipine in over 11,000 people. These studies found that the drug rarely caused problems in dosages up 10 mg daily.

However, common side effects include:

  • edema, which is a swelling that occurs in different parts of the body, particularly the feet or ankles
  • dizziness
  • flushing
  • palpitations, which are feelings of a fast or irregular heartbeat

Less common side effects include:

Amlodipine can potentially interact with some other medications, including:

  • Simvastatin. The FDA recommends limiting the dosage of simvastatin to 20mg daily while also taking amlodipine.
  • CYP3A4 inhibitors. Medications that inhibit an enzyme called CYP3A4 can increase the concentration of amlodipine in the blood. These drugs include diltiazem, ketoconazole, itraconazole, and ritonavir. The FDA recommend that doctors monitor people who are taking both CYP3A4 inhibitors and amlodipine for symptoms of edema and low blood pressure.
  • Cyclosporine. In people who have had a kidney transplant, taking amlodipine and cyclosporine together may increase the levels of cyclosporine in the body.

It is essential that people inform their doctors about all the medications, herbs, and supplements they are currently taking before starting amlodipine or any other new medicines.

The FDA have issued several warnings for doctors to take note of when prescribing amlodipine. These include:

Hypotension

Amlodipine can cause hypotension, or low blood pressure, in some people, particularly those with severe aortic stenosis. Symptoms of hypotension include feeling faint, tired, and nauseous.

Increased angina or myocardial infarction

When starting or increasing the dosage of amlodipine, it can worsen symptoms of angina and increase the risk of heart attack in some people, particularly those with severe obstructive coronary disease. However, this is rare.

Liver problems

The liver extensively metabolizes amlodipine, so doctors need to be cautious when prescribing this drug to people with liver conditions. The FDA recommend that doctors closely monitor these individuals and increase the dosages of amlodipine slowly.

The FDA have also highlighted some considerations that both the prescribing doctor and the person taking amlodipine need to be aware of. These include:

Pregnancy

There is a lack of research into the safety of taking amlodipine during pregnancy. The FDA recommend that doctors should only prescribe amlodipine to pregnant women if the potential benefits outweigh the risks to the fetus.

Breastfeeding

Scientists have not yet determined whether amlodipine can enter a woman's breast milk. Because of this, the FDA recommend that women do not take amlodipine while breastfeeding.

Children under 6 years

Due to a lack of studies, doctors do not know how safe or effective amlodipine is in children under the age of 6 years.

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Alternative medications are available.

Possible alternative medications to amlodipine include other calcium channel blockers, such as nicardipine, clevidipine, and nifedipine

However, doctors often prescribe amlodipine over some other medications because a person usually only needs to take one dose per day.

If a person experiences side effects on amlodipine, they should speak to a doctor about changing medication.

Amlodipine is an oral medication that doctors prescribe to treat high blood pressure, coronary artery disease, and angina. It is generally a safe and effective drug, but it may cause side effects in some people.

However, a doctor may recommend a lower dosage and close monitoring for some individuals taking amlodipine, such as older people, pregnant women, and people with liver conditions. Amlodipine can also interact with some other medications.

A person should speak to their doctor if they have any concerns about taking amlodipine or are experiencing any troubling side effects.