Midazolam is a widely used medicine in hospitals. Doctors often give it to patients before surgery to help them feel calm and sleepy. It works so well that most people don’t even remember the surgery afterward.
For years, it has been considered safe and useful. But now, new research is showing that the time of day when this medicine is given might make a big difference.
Researchers at the University of Colorado Anschutz Medical Campus discovered something surprising. They found that midazolam may increase the risk of heart damage — but only when it is given at night. This raises an important question: does the timing of medicine matter more than we thought?
To find answers, the scientists studied medical records from more than 1.7 million surgeries where midazolam was used. They looked closely at the cases to see when the medicine was given and whether the patients experienced any heart problems.
Out of all those cases, around 16,000 patients showed signs of heart injury. At first, this might not seem unusual, since heart problems can happen during surgery.
But when the scientists looked at the timing more closely, they noticed a pattern: patients who had surgery at night were more likely to have heart damage. This was even true for people who were otherwise healthy.
So, why would the same medicine cause more harm at night?
To understand this, the scientists looked deeper into how midazolam works in the body. Midazolam affects a chemical in the brain called GABA, which helps us feel calm and relaxed. But this calming effect may also change how certain genes work — including one called the PER2 gene.
The PER2 gene is very important for the heart. It helps protect the heart from injury. What’s interesting is that this gene is controlled by light. In other words, it works differently during the day and at night.
In animal studies with mice, the researchers found that midazolam reduces the activity of the PER2 gene more at night than during the day. With less PER2 at night, the heart becomes more vulnerable to damage.
This discovery shows how our body’s internal clock, also known as the circadian rhythm, plays a big role in how medicines affect us. The circadian rhythm controls our sleep, energy, and even how our organs function throughout the day. That means the same drug can have very different effects depending on the time it is given.
Other research has already shown that some medicines, like blood pressure drugs, work better or cause fewer side effects when taken at certain times of day. This new study adds to that growing list and suggests we should think more carefully about when we give medicines like midazolam.
Dr. Tobias Eckle, who led the research, believes that timing should be a key part of how doctors give treatments in the future. His team’s findings were published in a journal called Frontiers in Cardiovascular Medicine.
In the end, this study is a reminder that even common, trusted medicines can behave in unexpected ways. By learning more about how timing affects drug safety, scientists and doctors hope to make surgeries safer and save more lives.
If you care about heart health, please read studies about the best time to take vitamins to prevent heart disease, and scientists find how COVID-19 damages the heart.
For more information about heart health, please see recent studies about Aspirin linked to higher risk of heart failure, and results showing Blackcurrants could improve artery functions, blood pressure in older people.
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