Before many medical procedures or surgeries, doctors often give patients a drug called midazolam. This medication is commonly used to help people relax, reduce anxiety, and feel calm before and during procedures.
In many cases, it also causes partial memory loss, so patients do not remember uncomfortable or stressful moments. Because of these effects, midazolam has been widely used for many years and is generally considered safe.
However, new research suggests that this drug may not affect the body in the same way at all times of day. Scientists at the University of Colorado Anschutz Medical Campus have found that when midazolam is given at night, it may increase the risk of heart injury, even in patients who are otherwise healthy.
To explore this possible risk, the researchers analyzed more than 1.7 million medical records from patients who received midazolam during medical procedures. These records covered a wide range of patients, procedures, and hospital settings, giving the scientists a large and detailed set of real-world data.
Within this massive dataset, the researchers identified more than 16,000 cases in which patients experienced some form of heart damage after receiving the drug.
When the team looked more closely at when these procedures took place, a clear pattern began to emerge. Patients who received midazolam during nighttime procedures were more likely to suffer heart injury than those who received the same drug during the day.
This increased risk was especially noticeable in patients who did not already have heart disease or other serious health problems, which made the finding even more concerning.
The researchers wanted to understand why the time of day might make such a difference. To do this, they turned their attention to the body’s internal clock, also known as the circadian rhythm.
This natural system follows a roughly 24-hour cycle and helps control many important functions, including sleep, hormone release, metabolism, and heart protection. One key part of this system is a gene called PER2, which plays an important role in helping the heart defend itself against stress and injury.
Previous research has shown that PER2 activity changes between day and night. During certain times, this gene helps activate protective processes in heart cells. The scientists suspected that midazolam might interfere with this natural protection, especially at night when the body’s rhythms are different.
To test this idea, the research team conducted experiments using mice. These animal studies allowed them to closely examine how midazolam affects the brain and heart at different times of day.
They found that midazolam increases levels of a calming chemical in the brain called GABA. This chemical helps reduce anxiety and promote relaxation, which is why the drug works so well for sedation.
However, the researchers also discovered that increased GABA activity at night reduced the activity of the PER2 gene. Because PER2 helps protect the heart, lowering its activity during nighttime hours made the heart more vulnerable to injury.
In other words, while the drug was calming the brain, it was also weakening a natural heart defense system during a sensitive time of day.
These findings suggest that the timing of certain medications can be just as important as the medication itself. A drug that is safe and helpful during the day may carry extra risks when given at night. In the case of midazolam, nighttime use may increase the chance of heart injury, particularly in patients who might otherwise be considered low-risk.
The study was led by Tobias Eckle and published in the journal Frontiers of Cardiovascular Medicine. It adds strong support to the growing field of time-based or personalized medicine, which aims to match treatments not only to individual patients but also to the body’s natural daily rhythms.
Some medications are already prescribed with timing in mind. For example, certain blood pressure drugs are known to work better when taken at night. This new research suggests that similar thinking may be needed for sedatives and other commonly used hospital drugs.
By paying closer attention to when medications are given, doctors may be able to reduce side effects, protect vital organs like the heart, and improve recovery after surgery.
This study highlights the powerful connection between our biological clocks and medical treatments and points toward a future where the right time may be just as important as the right drug.
If you care about heart disease, please read studies that herbal supplements could harm your heart rhythm, and how eating eggs can help reduce heart disease risk.
For more health information, please see recent studies that apple juice could benefit your heart health, and results showing yogurt may help lower the death risks in heart disease.
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