A large study has found that a commonly used heart medicine may increase the risk of serious bleeding in older people with atrial fibrillation, also known as AFib.
The research, published in the medical journal JAMA, raises important questions about how different heart medicines interact inside the body and why some patients may face greater risks than others.
AFib is the most common type of irregular heartbeat in the world. It happens when the upper chambers of the heart beat in a fast and uneven way instead of following a normal rhythm.
This can make blood move poorly through the heart, increasing the risk of blood clots. If a clot travels to the brain, it can cause a stroke, which may lead to disability or death.
Because of these dangers, many people with AFib take blood-thinning medicines to lower their risk of stroke. These medicines help stop dangerous clots from forming. Doctors also often prescribe drugs that slow down the heart rate and help the heart beat more steadily.
However, combining several medicines can sometimes create unexpected problems. Different drugs may affect how the body processes medications, especially in older adults whose organs may not work as efficiently as they did earlier in life.
Researchers from Northwestern University wanted to better understand these risks. The team studied people aged 65 and older who were enrolled in Medicare in the United States.
They focused on patients who were taking one of two widely used blood thinners, apixaban or rivaroxaban. These medicines are commonly prescribed for AFib because they help reduce stroke risk without requiring as much monitoring as older blood thinners such as warfarin.
The researchers then looked at which patients were also taking either diltiazem or metoprolol. Both medicines are often used to control heart rate in people with AFib. The study examined patients who started these treatments between 2012 and 2020.
The results showed a clear difference between the two groups. People taking diltiazem together with blood thinners were about 20% more likely to be hospitalized or die because of serious bleeding compared to people taking metoprolol with the same blood thinners.
This finding surprised researchers because both medicines are commonly used and considered effective for controlling heart rate.
While diltiazem can help the heart beat more slowly and regularly, it may also affect how the body handles blood-thinning drugs. This interaction could raise the amount of blood thinner in the body, increasing the risk of bleeding.
The study did not find major differences between the groups when it came to stroke, blood clots, or other less severe bleeding problems. The main concern was the higher rate of serious bleeding events in people taking diltiazem.
Serious bleeding can happen in many parts of the body. Some people may experience bleeding in the stomach or intestines, while others may develop dangerous bleeding in the brain. Older adults are especially vulnerable because aging can weaken blood vessels and reduce the body’s ability to recover from blood loss.
Dr. Eli Zimmerman, one of the study authors and a professor at Northwestern University, said the findings show why personalized medicine is becoming increasingly important.
Not everyone responds to medicines in the same way. Genetics, age, kidney function, liver health, and other medical conditions can all affect how drugs work inside the body.
Researchers believe future treatment may become more individualized. Instead of giving the same medicine combinations to everyone, doctors may eventually use genetic testing or blood monitoring to choose safer treatments for each patient.
The research team is now exploring whether checking drug levels in the blood could help lower bleeding risks. If doctors can identify patients whose bodies are processing medicines too slowly, they may be able to adjust doses before dangerous bleeding occurs.
The study also highlights the growing challenge of caring for older patients with multiple health problems.
Many older adults take several medicines every day for conditions such as high blood pressure, diabetes, heart disease, and arthritis. The more medicines a person takes, the greater the chance of drug interactions and side effects.
Heart health is also affected by lifestyle choices. Experts say medicine works best when combined with healthy habits. Eating nutritious foods, staying physically active, sleeping well, and reducing stress can all support heart health.
Some studies suggest that eating meals earlier in the day may help improve blood pressure. Plant-based diets rich in fruits, vegetables, beans, and whole grains may also reduce the risk of heart disease.
People with high blood pressure are sometimes advised to limit caffeine intake as well, since too much coffee may temporarily raise blood pressure in sensitive individuals.
Doctors say patients should never stop taking heart medicines on their own after hearing about studies like this.
Suddenly stopping blood thinners or heart medications can be dangerous and may increase the risk of stroke or other serious problems. Instead, patients should talk with their doctors about whether their current treatment plan is still the safest choice.
The researchers say this study is another reminder that modern medicine can be complicated. A drug that helps one condition may create risks somewhere else in the body. Understanding these interactions more clearly may help doctors make safer decisions for millions of people living with AFib.
If you care about high blood pressure, please read studies that early time-restricted eating could help improve blood pressure, and natural coconut sugar could help reduce blood pressure and artery stiffness.
For more health information, please see recent studies about added sugar in your diet linked to higher blood pressure, and results showing vitamin D could improve blood pressure in people with diabetes.
The study was published in JAMA.
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