Tylenol is at the top of everyone’s minds today after President Trump announced a label change from the U.S. Food and Drug Administration that states using the medication during pregnancy can lead to a “very increased risk of autism.”
Despite long-standing evidence of no direct link, the FDA said in a statement, “Evidence in recent years has suggested a correlation between acetaminophen use during pregnancy and subsequent diagnosis of conditions like autism and ADHD.”
Related: N.J.-based Tylenol maker ‘deeply concerned,’ defends drug against autism link
However, it adds, “It is important to note that while an association between acetaminophen and neurological conditions has been described in many studies, a causal relationship has not been established and there are contrary studies in the scientific literature.”
Medical experts say autism has many causes because it is complex and has varied symptoms and severity, though “genetics and environment may play a role,” according to Mayo Clinic. However, based on several studies, they have not been able to conclude that Tylenol use during pregnancy is associated with autism risk.
With all the concern and confusion around Tylenol, people have many questions about the drug, acetaminophen and when it became available to the public.
Here’s what you need to know about the common over-the-counter pain reliever.
When was acetaminophen invented?
Acetaminophen, the active ingredient in Tylenol, was discovered in 1878 by accident, according to the FDA. It originally came from coal tar, like most medications.
“A researcher investigating a treatment for intestinal worms asked for a product to study, but was given the wrong chemical instead—acetanilide—that had no effect on worms. It did, though, lower fever,” Tufts University School of Medicine says.
Acetaminophen is derived from acetanilide, but it has fewer side effects and is considered a safer alternative.
Seventy-seven years later, in 1955, the pharmaceutical company McNeil Laboratories developed the brand of acetaminophen called Tylenol.
It was the first pain reliever without aspirin available to the general public to purchase. The first variety was Children’s Tylenol Elixir, which was only available to purchase with a prescription, according to Kenvue, its current brand owner.
Kenvue acquired McNeil Laboratories and the Tylenol brand in 1959. That same year, Tylenol was approved for consumers to buy without a prescription and became available to purchase over the counter in 1960.
Read More: Tylenol-maker says ignore that old tweet about pregnant women. Here’s what we really meant.
What is acetaminophen used for?
Acetaminophen is used as a fever reducer and provides relief for mild to moderate pain.
However, researchers have not been able to determine exactly how it works in the central nervous system.
Many people use it for temporary relief of the following forms of pain:
headache
backache
minor pain of arthritis
toothache
muscular aches
premenstrual and menstrual cramps
Medical experts also consider Tylenol or acetaminophen to be safe to use during pregnancy for fever and minor pain reduction, according to several studies, including a recent study from 2024. That’s in contrast to ibuprofen (Advil) and naproxen (Aleve), for which evidence has shown may affect fetal development during pregnancy, according to the Cleveland Clinic.
However, it’s important to acknowledge the medication’s impact on the liver in high doses. While it’s harmless in low doses and when used as directed, “it can cause acute liver injury and death from acute liver failure” in high doses, according to the National Institutes of Health.
Do other countries, like Cuba, use acetaminophen?
Yes, acetaminophen is used in most countries for fever reduction and pain relief. According to ACS, “it’s one of the most widely used pain relievers.”
However, it is called acetaminophen in only a few countries, including the U.S., Canada and Japan.
Cuba, Europe and several other countries call the drug paracetamol or other brand names, like Panadol and Calpol.
According to Drugs.com, other popular international brand names for paracetamol include:
Disprol
Hedex
Medinol
Alvedon
However, according to Eurovision News Spotlight, access to paracetamol in Cuba is limited due to shortages of the medication.