September 21, 2025
2 min learn
No one Is aware of How Tylenol Actually Works
The widespread ache reliever is protected when used as directed, analysis exhibits. However scientists stay puzzled by one side: the way it reduces ache and fever
Tylenol is utilized by hundreds of thousands for ache reduction.
Brendan Smialowski/Stringer/Getty Photographs
You’re unlikely to open a medication cupboard within the U.S. with out seeing a bottle of Tylenol, the model title of a ache reliever and fever reducer additionally offered generically as acetaminophen. A well being care commerce affiliation estimates that 52 million shoppers use a product containing acetaminophen each week within the U.S. The drug is within the information at this time after Robert F. Kennedy, Jr., head of the Division of Well being and Human Companies, implied that acetaminophen that’s taken when an individual is pregnant could cause autism in that particular person’s offspring. His statements run counter to essentially the most conclusive scientific proof so far.
The drug is protected and efficient when used as directed, however there’s something shocking about it: nobody is for certain how acetaminophen works to alleviate ache and fever.
There are at the least two theories concerning the mechanism of the drug, which was first synthesized within the late 1800s. One is that the treatment works by interfering with cyclooxygenase (COX) enzymes, which in the end result in the formation of prostaglandins, substances that may heighten ache sensations and drive irritation and fever. By interfering with a type of COX enzymes, acetaminophen inhibits these prostaglandins from forming, says Steven Dudley, a medical toxicologist and pharmacist, who directs the Arizona Poison and Drug Data Middle on the College of Arizona. “So it’s in all probability an oblique impact on prostaglandins,” Dudley says.
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The opposite thought is that the treatment acts on physique chemical substances known as endogenous cannabinoids, says Alex Straiker, a neuropharmacologist at Indiana College’s Gill Institute for Neuroscience. Straiker has researched the mechanism and located that acetaminophen inhibited cannabinoid manufacturing in rodents and that this decreased their ache response.
“Ache pathways are very sophisticated,” Straiker says. “So acetaminophen is prone to have a number of targets.” It may have an effect on each prostaglandins and cannabinoids, or it may act on different substances concerned in ache notion, such because the neurotransmitter serotonin. Each he and Dudley say the treatment’s glorious efficiency could have decreased scientific curiosity in understanding the mechanism with a view to enhance it. “There could possibly be no huge incentive to determine the way it works,” Straiker says.
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