Acetaminophen is one of the most common medicines in the world. People often use it to treat headaches, fevers, or mild pain.
You may know it by brand names like Tylenol or Panadol. Most of the time, we take it as a pill or tablet, and when used properly, it’s very safe.
That’s why it’s found in almost every home and doesn’t need a prescription.
In hospitals, though, doctors sometimes give acetaminophen in a different way. Instead of giving a pill, they put the medicine directly into the patient’s bloodstream through a needle. This method is called IV (short for intravenous) delivery.
There are good reasons for using an IV. It works faster because the medicine goes straight into the blood. It also helps hospital staff control exactly how much medicine a patient receives. This is useful for very sick patients who can’t swallow pills.
However, new research has shown something surprising. When acetaminophen is given by IV, it can cause a person’s blood pressure to drop. This drop doesn’t just happen in very sick people—it can happen in anyone who gets the medicine through an IV.
One study found that around 6 out of 10 critically ill patients who got IV acetaminophen had a big drop in blood pressure. About a third of them even needed extra treatment to bring their blood pressure back up. Still, acetaminophen is widely used in hospitals because it usually works well and is safe when monitored.
So, why does this happen? A team of scientists led by Thomas Qvistgaard Jepps at the University of Copenhagen wanted to find out. They discovered that acetaminophen acts differently in the body depending on how it’s given.
When you swallow a pill, the medicine goes to your liver first. The liver changes it slightly before it moves through your body. But when it’s given through an IV, it skips the liver at first and goes straight into your bloodstream. This leads to the creation of different chemicals in the body.
These chemicals seem to affect something called potassium channels. Potassium channels are tiny parts in the walls of blood vessels that help control how wide or narrow the vessels are. They help regulate your blood pressure.
If these potassium channels are affected, blood vessels can open too wide. This makes blood pressure drop. In experiments with rats, researchers were able to stop this drop by blocking the potassium channels. That shows the channels may play a big role in how IV acetaminophen affects blood pressure.
This finding is important, especially during times like the COVID-19 pandemic when many people in hospitals needed IV medicine. It helps doctors and nurses understand what to watch out for and how to keep patients safe.
If you’re someone who takes acetaminophen at home as a pill, there’s no need to worry. This side effect only happens with IV use. As long as you follow the directions on the package and don’t take too much, acetaminophen is still a very safe and helpful medicine.
This study shows us that even well-known drugs can act differently depending on how they are given. It’s a reminder that medicine is not one-size-fits-all, and doctors are always learning more about how to make treatments safer and better.
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