A new study from the University of Copenhagen has helped explain why some people experience a big drop in blood pressure after receiving acetaminophen (also known as paracetamol) through an IV.
This painkiller is very common and is usually taken by mouth for headaches and other aches. But in hospitals, especially for patients who can’t swallow, doctors give it through a vein.
IV acetaminophen has some big advantages. It works faster than pills, allows more accurate dosing, and is a good option for very sick patients. However, doctors have noticed that it sometimes causes a sharp and sudden drop in blood pressure. This can be dangerous, especially for people who are already critically ill.
The researchers found that about 6 out of 10 critically ill patients experience this drop in blood pressure after getting IV acetaminophen. For about a third of these patients, the blood pressure drop is so serious that they need extra medical care to bring it back up. Still, acetaminophen remains widely used because it is usually safe when given properly.
To find out why this side effect happens, scientists looked into how the body breaks down the drug. When acetaminophen is taken by mouth, it goes through the liver first.
But when it’s given through an IV, it skips the liver and gets processed in other parts of the body. This leads to the creation of leftover chemicals, or byproducts, that can affect the body in unexpected ways.
One way these byproducts affect the body is through potassium channels. These channels help control how blood vessels tighten or relax, which directly affects blood pressure. The study showed that these leftover chemicals from IV acetaminophen can cause blood vessels to relax too much, which makes blood pressure drop quickly.
To test their theory, the researchers gave rats a drug that blocks specific potassium channels. When they did this, the rats didn’t have as big of a blood pressure drop from IV acetaminophen. This suggests that blocking these channels could be a way to reduce this side effect in patients.
The good news is that this side effect mostly happens with IV acetaminophen. If you are taking acetaminophen by mouth at the recommended dose, it is still very safe. The researchers don’t want people to stop using it for everyday pain.
This research is especially important now, during the COVID-19 pandemic, when IV acetaminophen is being used more often in hospitals to treat fever and pain. It may help doctors find better ways to keep patients safe when using this drug.
For people who want to manage their blood pressure in general, other studies have found that olive oil may help lower blood pressure. Vitamin B is also being looked at as a possible treatment for tough cases of high blood pressure.
This study was led by Thomas Qvistgaard Jepps and published in the journal Atherosclerosis, Thrombosis, and Vascular Biology. It gives new insight into how a common drug works in the body and how to make its use safer in hospitals.
If you care about blood pressure, please read studies about unhealthy habits that could increase high blood pressure risk, and eating eggs in a healthy diet may reduce risks of diabetes, high blood pressure.
For more information about blood pressure, please see recent studies that early time-restricted eating could help improve blood pressure, and results showing 12 foods that lower blood pressure.
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