Acetaminophen is one of the most commonly used painkillers in the world. You’ve probably taken it yourself for a headache, fever, or sore muscles. It’s often seen as a safe and easy way to get quick relief from pain or discomfort.
Usually, people take acetaminophen as a tablet or capsule. But in hospitals, doctors often give it in a different way—by injecting it straight into a patient’s bloodstream. This method is called “intravenous” or IV delivery.
There are good reasons for this. When given through an IV, acetaminophen works faster. It also allows doctors to control the exact amount of medicine a patient gets, and it’s helpful for patients who are too sick to swallow pills.
But a recent study from the University of Copenhagen has found something surprising: when acetaminophen is given through an IV, it can cause a sudden drop in blood pressure. This can be dangerous, especially for people who are already very sick.
The study found that about 60% of critically ill patients experienced this drop in blood pressure, and about one-third of them needed emergency help because of it.
The study was led by researcher Thomas Qvistgaard Jepps. His team wanted to understand why this happens. They discovered that when acetaminophen is given directly into the bloodstream, it bypasses the liver—the organ that usually helps process the drug.
This changes the way the body breaks down the medicine. As a result, it creates different byproducts—small chemicals that can affect how the body works.
These byproducts were found to affect something called potassium channels. Potassium channels are tiny pathways in our blood vessels that help control how wide or narrow the vessels are. When these channels are affected, blood vessels can widen too much, which lowers blood pressure.
To confirm their theory, the scientists tested this on lab rats. When they blocked the potassium channels, the rats no longer experienced a big drop in blood pressure after receiving acetaminophen. This suggests that the potassium channels play a key role in the side effect.
So, what does this mean for you? If you take acetaminophen in pill form at home and follow the instructions on the label, there is no need to worry. This side effect mainly applies to people in hospitals who are receiving high doses through an IV.
But for doctors and nurses, this study is important. It helps explain why some patients in the hospital may suddenly experience low blood pressure after receiving IV acetaminophen. And it may lead to safer ways to give this medicine in the future, especially for people who are already very ill.
This research is particularly important during times when many people are being treated in hospitals, like during the COVID-19 pandemic. Knowing more about how common medicines affect the body can help save lives and improve patient care.
The full study was published in the journal Atherosclerosis, Thrombosis, and Vascular Biology.
If you care about blood pressure, please read studies that black licorice could cause dangerous high blood pressure, and this common plant nutrient could help reduce high blood pressure.
For more information about blood pressure, please see recent studies about how coffee influence your risk of high blood pressure, and results showing this olive oil could reduce blood pressure in healthy people.
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