Sudden cardiac arrest is one of the most serious medical emergencies. It happens when the heart suddenly stops pumping blood effectively, cutting off the supply of oxygen to the brain and the rest of the body.
Within seconds, a person loses consciousness and stops breathing normally. Without immediate treatment, such as cardiopulmonary resuscitation (CPR) and an automated external defibrillator (AED), sudden cardiac arrest is often fatal within minutes.
Unlike a heart attack, which is caused by blocked blood flow to the heart muscle, sudden cardiac arrest is mainly a problem with the heart’s electrical system, although a heart attack can sometimes trigger it.
Sudden cardiac arrest can affect people of different ages, but the risk is higher in those with heart disease, high blood pressure, or certain heart rhythm disorders. It is one of the leading causes of death in Europe, accounting for about half of all deaths related to heart disease and about one in every five natural deaths.
Some people experience warning signs such as chest pain, dizziness, shortness of breath, nausea, or a racing heartbeat before collapsing. However, many people have no warning symptoms at all, making prevention extremely difficult.
A new study by researchers from the European Sudden Cardiac Arrest network has raised concerns about one of the world’s most commonly prescribed blood pressure medicines.
The researchers found that people taking high doses of nifedipine may have a greater risk of sudden cardiac arrest. Their findings suggest that doctors should carefully consider the dose prescribed, although patients should not stop taking their medicine without medical advice.
High blood pressure, also known as hypertension, affects millions of people worldwide. Over time, it damages blood vessels and greatly increases the risk of heart attacks, strokes, heart failure, and kidney disease. Medicines are often needed when lifestyle changes alone cannot control blood pressure.
Nifedipine is a calcium channel blocker, a type of medicine that relaxes blood vessels so blood can flow more easily. This lowers blood pressure and reduces the workload on the heart. Another medicine in the same drug family is amlodipine, which works in a similar way and is also widely prescribed.
To investigate whether these medicines influenced the risk of sudden cardiac arrest, researchers analyzed information from two very large groups of people. The first group came from the Netherlands and included more than 2,500 people who experienced sudden cardiac arrest and over 10,500 healthy individuals for comparison.
The researchers found that people taking a high dose of nifedipine, equal to 60 milligrams each day, had a higher chance of experiencing sudden cardiac arrest. In contrast, people taking amlodipine did not show the same increase in risk.
Because important medical discoveries need confirmation, the scientists examined a second large database from Denmark. This included more than 8,000 people who had suffered sudden cardiac arrest and over 40,000 healthy comparison participants.
The Danish results closely matched the findings from the Netherlands, strengthening the evidence that high-dose nifedipine may be linked to an increased risk.
The researchers were surprised because both nifedipine and amlodipine have been used safely for many years. Earlier studies had not identified this possible risk, partly because sudden cardiac arrest occurs without warning and is difficult to investigate in large numbers of patients.
It is important to understand that this study found an association rather than proving that nifedipine directly causes sudden cardiac arrest. More research is needed to discover why the higher risk was seen and whether certain patients are more vulnerable than others.
The researchers are not recommending that people stop taking nifedipine. Suddenly stopping blood pressure medicine can be dangerous and may increase the risk of serious heart problems.
Instead, patients who take high doses of nifedipine should discuss the findings with their doctor. In some cases, another medicine such as amlodipine may be a suitable alternative, but treatment decisions should always be made by a healthcare professional.
This study also shows why medicines must continue to be monitored even after they have been used for many years. Large studies can sometimes uncover uncommon side effects that were difficult to detect in earlier research. Continued research helps improve patient safety and allows doctors to make better treatment decisions.
Along with taking prescribed medicines correctly, people can lower their risk of heart disease by eating a healthy diet, exercising regularly, avoiding smoking, maintaining a healthy weight, and keeping blood pressure, cholesterol, and diabetes under good control. These healthy habits remain an important part of protecting the heart.
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