Midazolam is a medicine that helps people feel calm or sleepy before surgery. It works so well that most people don’t even remember the surgery afterward.
But a new study has found that giving this drug at night might have a surprising and serious side effect—it could harm the heart.
Researchers at the University of Colorado Anschutz Medical Campus looked at more than 1.7 million patient records. All of these patients received midazolam before their surgeries. Out of them, over 16,000 showed signs of heart damage after surgery.
The researchers noticed something interesting: people who had surgery at night were more likely to have heart problems afterward. This was especially true for patients who were otherwise healthy.
The scientists wanted to understand why the time of day could make a difference. Their search led them to a gene called PER2. This gene helps protect the heart and is linked to our body’s natural 24-hour clock, called the circadian rhythm. The circadian rhythm controls how our bodies react to light and dark and plays a big role in keeping us healthy.
In tests with mice, the researchers discovered that midazolam can reduce the levels of the PER2 gene at night. This is a problem because the heart needs the protection that PER2 provides. Since PER2 is already lower at night, and midazolam makes it drop even more, the heart is left more vulnerable during nighttime surgeries.
Midazolam works by increasing a calming chemical in the brain called GABA. This helps people relax, which is why it is often used before surgery. But this calming effect may also affect how the heart protects itself, especially at night when the body’s natural defenses are lower.
This study shows that the timing of a drug can be just as important as the drug itself. Our bodies respond differently to medicines depending on what time it is. This area of research is called chronomedicine. It studies how the time of day can change how well a drug works or how safe it is.
Some medications, like those for high blood pressure, are already known to work better when taken at night. Now, this study suggests that we should think about the timing of sedatives like midazolam too—especially if the surgery is at night and the patient is otherwise healthy.
The study was led by Dr. Tobias Eckle and published in the journal Frontiers in Cardiovascular Medicine. It shows that even small details—like what time a medicine is given—can make a big difference in health and safety.
Even though midazolam is a very common and helpful drug, this research helps doctors use it more wisely. Knowing the best time to give it could help protect patients’ hearts and improve the safety of surgeries.
If you care about heart health, please read studies about how eating eggs can help reduce heart disease risk, and Vitamin K2 could help reduce heart disease risk.
For more information about heart health, please see recent studies about how to remove plaques that cause heart attacks, and results showing a new way to prevent heart attacks, strokes.
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