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  • Amlodipine, a treatment for high blood pressure, is safe and effective, new research shows.
  • Earlier research raised concerns about an increased risk of heart failure from taking amlodipine and similar calcium channel blockers.
  • The new study refuted these earlier results and found that amlodipine may decrease the risk of heart failure and and other cardiovascular outcomes.

One of the most common drugs for treating high blood pressure (hypertension), amlodipine, is safe and effective, according to new research.

Amlodipine, sold under the brand name Norvasc among others, is a calcium channel blocker used to treat high blood pressure, angina, and coronary artery disease.

In 2020, it was the fifth most commonly prescribed medication in the United States, with more than 69 million prescriptions, according to data from the Agency for Healthcare Research and Quality.

The new research follows an earlier study which raised concerns that taking amlodipine could lead to changes in the blood vessels that increase the risk of heart failure.

Experts interviewed by Healthline say the new research refutes those earlier concerns, and reaffirms that amlodipine is a safe and effective treatment for high blood pressure.

Approximately 700,000 Americans die each year from high blood pressure, according to the Centers for Disease Control and Prevention.

However, only about one in four Americans with high blood pressure have it under control, reports the agency. Left untreated, high blood pressure increases the risk of heart attack, stroke, kidney disease and eye damage.

Amlodipine has been prescribed to treat high blood pressure for more than 30 years. It is also included on the World Health Organization’s list of essential medicines.

This medication works by blocking a certain type of calcium channel known as a voltage-dependent channel, which prevents the influx of calcium into cells with this type of channel.

Blocking the influx of calcium causes the muscles of the blood vessels to relax, which leads to a widening of the blood vessels and reduced blood pressure.

In an earlier study, researchers reported that amlodipine and similar calcium channel blockers activated a different type of channel, known as a store-operated calcium channel.

This results in vascular remodeling — changes in the blood vessels — that often occurs in people with high blood pressure, they reported.

That study also included an analysis of patient records, which found that patients treated exclusively with amlodipine or similar calcium-channel blockers had a higher risk of heart failure compared to those who did not receive one of these medications.

In the new research, published Oct. 12 in the journal Function, researchers noted that the concentration of amlodipine needed to activate store-operated calcium channels in the earlier laboratory study is much higher than the dose people would get by taking the drug as prescribed.

The authors of the new study also carried out a meta-analysis of previous clinical trials, along with a real-world analysis of over 63,000 people with high blood pressure.

They found that amlodipine and similar calcium channel blockers were associated with a lower risk of heart failure and other cardiovascular outcomes during a one-year follow-up, compared to other blood pressure medications.

Dr. Daniel Kiss, interventional cardiologist at Jersey Shore University Medical Center and Hackensack Meridian Health AngioScreen medical director in New Jersey, said the earlier research is an example of an observational study, which may suggest a link between two factors but can’t prove that one causes the other.

“When further study is pursued, as in the case of the new research, it refutes the concern raised by the original study,” he told Healthline. So “the new study confirms the safety and efficacy of amlodipine as a first line therapy for hypertension.”

Dr. Guy L. Mintz, director of Cardiovascular Health & Lipidology at Sandra Atlas Bass Heart Hospital at North Shore University Hospital in Manhasset, New York, said the earlier study also did not differentiate between the various calcium channel blocker medications, which may have led to the study’s negative findings.

In addition, “some calcium channel blockers — such as verapamil or diltiazem, which decrease heart function — should not be given in [people with] heart failure,” he told Healthline.

Kiss said the new study reinforces amlodipine’s role as a first-line medication for treating high blood pressure, especially with other research showing that it lowers the risk of heart attack and stroke.

“It is very effective, well-tolerated and has minimal side effects,” he said. “The biggest concern when using this medicine is swelling of the lower extremities, so I try avoiding it in patients prone to such swelling.”

Mintz agreed that amlodipine is a safe and effective therapy for high blood pressure, pointing out that it may even have a protective effect against heart failure.

“I have personally prescribed amlodipine to thousands of patients without any developing heart failure from this medication,” he said.

He also said that Black people with high blood pressure may especially benefit from the use of calcium channel blockers.

Clinical practice guidelines recommend the use of a calcium channel blocker along with a thiazide diuretic or other medication in this group, which has a higher risk of kidney disease, stroke, heart failure and death.

Given the new study and other research, “people taking amlodipine should not be concerned about heart failure risk,” said Mintz. “They are being treated with an effective and safe anti-hypertensive agent.”

He also emphasized that “patients should never stop [taking] hypertensive therapy without talking to their physician about their concerns.”

Kiss agreed, pointing to “the importance of trust in a healthy doctor-patient relationship, and [making sure] that the prescriber is up to date on current literature and guidelines.”

A new study found that the calcium channel blocker amlodipine is a safe and effective treatment for high blood pressure, refuting an earlier study that found a higher risk of heart failure due to changes in the blood vessels.

Experts say the new study and other research reinforce the role of amlodipine as a first-line treatment for high blood pressure. This medication is well-tolerated and has minimal side effects.

Untreated high blood pressure can lead to an increased risk of heart attack, stroke, kidney disease and eye damage. Only one-quarter of Americans with high blood pressure have it well-controlled, CDC data shows.