Midazolam is a medicine that helps people feel calm or sleepy before surgery. It works very well, and most patients don’t remember anything about the surgery afterward. But a new study shows that giving midazolam at night might have a serious side effect—it could harm the heart.
Scientists at the University of Colorado Anschutz Medical Campus studied more than 1.7 million patient records. All of these patients were given midazolam before their operations. Out of all those people, over 16,000 showed signs of heart injury after surgery.
When the researchers looked more closely, they noticed something interesting. The risk of heart injury was higher in patients who had surgery at night, especially those who were otherwise healthy. This surprising result made them ask: Why does the time of day matter?
The answer may lie in a special gene called PER2. This gene helps protect the heart and is part of our body’s internal clock, also called the circadian rhythm. The circadian rhythm controls how our body works during the day and night and is affected by light.
In tests with mice, the scientists found that midazolam can lower the amount of PER2 during the night. That’s a problem because PER2 is most needed at night to protect the heart. If midazolam reduces PER2 at that time, the heart may be more likely to get injured.
Midazolam works by increasing a calming chemical in the brain called GABA. This helps people relax, which is why it’s used before surgery. But the calming effect also seems to weaken the heart’s natural protection system—especially at night when PER2 is already low.
This study shows that the timing of medication can be just as important as the medicine itself. Our bodies react differently to drugs depending on the time of day. The area of research that looks at this is called chronomedicine.
Some medicines, like those for high blood pressure, are already known to work better at night. Now, this study suggests we should also think about when to give sedatives like midazolam—especially during nighttime surgeries and in patients who are otherwise healthy.
The research was led by Dr. Tobias Eckle and published in the journal Frontiers in Cardiovascular Medicine. It’s a great example of how scientists are always working to make treatments safer. Even though midazolam is helpful and widely used, knowing the best time to give it might prevent heart problems in some patients.
This study reminds us that even small details—like the time of day—can make a big difference in keeping patients safe and healthy.
If you care about health, please read studies about the benefits of low-dose lithium supplements, and what we know about egg intake and heart disease.
For more health information, please see recent studies about potatoes and high blood pressure, and results showing 6 best breads for people with heart disease.
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