A recent study from the University of Copenhagen has uncovered why acetaminophen, a widely used painkiller, can cause a significant drop in blood pressure when administered intravenously.
While acetaminophen (also known as paracetamol) is commonly taken orally for headaches and other pain relief, hospitals often administer it intravenously for critically ill patients who cannot swallow pills.
Intravenous acetaminophen offers several advantages in a medical setting. It works faster than oral medication, allows precise dosing, and ensures effectiveness for patients who are unable to ingest tablets.
However, it has been known to cause a steep, temporary drop in blood pressure, which can be a serious side effect. This effect has been observed not only in critically ill patients but also in otherwise healthy individuals receiving the drug intravenously.
The study revealed that six out of ten critically ill patients experience this blood pressure drop after intravenous acetaminophen, with one-third requiring medical intervention to stabilize their condition. Despite this, the drug is still widely used in healthcare due to its overall safety and effectiveness when used correctly.
Researchers aimed to understand why this side effect occurs. They found that the way acetaminophen is metabolized differs significantly when given intravenously compared to being taken orally. When taken by mouth, acetaminophen is processed in the liver.
However, intravenous administration bypasses the liver, leading to metabolism in other parts of the body. This produces residual chemicals that can have unexpected effects, including influencing potassium channels.
Potassium channels play a critical role in regulating blood vessel contraction and relaxation, which directly impacts blood pressure. The study showed that residual products from intravenous acetaminophen interact with these channels, leading to blood vessel relaxation and a sudden drop in blood pressure.
To test this theory, researchers used drugs that block specific potassium channels in test rats and found that the large drop in blood pressure could be reduced or prevented. This discovery offers a potential pathway to mitigate this side effect in patients who need intravenous acetaminophen.
The researchers emphasize that this finding should not discourage the general public from using acetaminophen for common pain relief as long as it is taken within the recommended dose. The side effect appears to be specific to intravenous administration and primarily affects critically ill patients.
With the ongoing COVID-19 pandemic, the use of intravenous acetaminophen has likely increased in hospitals for managing pain and fever, making this research particularly relevant.
For those concerned about maintaining healthy blood pressure, other studies have suggested beneficial approaches such as using olive oil to lower blood pressure and exploring vitamin B as a potential treatment for drug-resistant hypertension.
This study, led by Thomas Qvistgaard Jepps and published in Atherosclerosis, Thrombosis, and Vascular Biology, sheds light on a key side effect of intravenous acetaminophen and suggests ways to address it, improving safety for patients who rely on this common pain medication in critical care settings.
If you care about high blood pressure, please read studies about unhealthy habits that may increase high blood pressure risk, and drinking green tea could help lower blood pressure.
For more information about high blood pressure, please see recent studies about what to eat or to avoid for high blood pressure, and 12 foods that lower blood pressure.
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