Prenatal Use of Acetaminophen Linked to Early Puberty

By Pat Anson, PNN Editor

The daughters of women who took acetaminophen during pregnancy tend to start puberty early, according to a new study by Danish researchers.  

The study is the latest indication that prenatal use of acetaminophen – more commonly known as paracetamol outside the U.S. -- can have long term effects on children.

Researchers at Aarhus University studied health data on about 100,000 Danish women who provided detailed information about their use of acetaminophen during pregnancy.

Nearly 16,000 children born to those mothers between 2000 and 2003 were followed from the age of eleven and throughout puberty, with surveys every six months about different aspects of their development.

The study, published in the American Journal of Epidemiology, found that girls on average entered puberty between one-and-a-half and three months earlier if their mothers took the over-the-counter pain reliever for more than 12 weeks during pregnancy.


"We found a 'dose-response' correlation. That is to say, the more weeks with paracetamol during pregnancy, the earlier puberty in girls, but not in boys," says lead author Andreas Ernst, a PhD student from the Department of Public Health at Aarhus University.

"While entering puberty one-and-a-half to three months earlier may seem unimportant, when taken together with the frequent use of paracetamol during pregnancy, our findings ought to make people take notice. Our results are certainly not the decisive factor that should change current practice, but the perception of paracetamol as 'the safe and harmless choice' during pregnancy ought to be challenged."

Early puberty development increases the risk of serious diseases in adulthood, such as obesity, diabetes, cardiovascular diseases and testicular and breast cancer.

The use of acetaminophen (paracetamol) has been increasing worldwide and studies have found that over half of pregnant women in the U.S. and European Union use the pain reliever at least once during their pregnancy. It is the active ingredient in Tylenol, Excedrin, and hundreds of pain medications.

Previous research has shown that prenatal use of acetaminophen is associated with slow language development, autism and attention deficit problems in young children.

Over 50 million people in the U.S. use acetaminophen each week to treat pain and fever. The pain reliever has long been associated with liver injury and allergic reactions such as skin rash. The FDA label for products containing acetaminophen warns about the risk of liver damage and other side effects but does not specifically warn pregnant women about using the pain reliever. The agency said in 2015 that the evidence was “too limited” to justify such a warning.  

In its 2016 opioid prescribing guidelines, the CDC recommends acetaminophen as an alternative to opioid pain medication. The guideline only briefly mentions that acetaminophen is involved in hundreds of overdose deaths annually and can cause liver problems.

The CDC guideline does warn pregnant women -- at length -- that opioids can cause birth defects, poor fetal growth, still births and neonatal opioid withdrawal syndrome.

Overuse of Acetaminophen Increases During Flu Season

By Pat Anson, Editor

Acetaminophen is a key ingredient in hundreds of over-the-counter pain relievers and cough, cold and flu medicines – from Excedrin and Tylenol to Theraflu and Alka-Seltzer Plus.

Recent guidelines released by the UK’s National Institute for Health Care Excellence (NICE) even recommend acetaminophen (paracetamol) for treating sore throat pain.

But a large new study warns that too many cold and flu sufferers take too much acetaminophen – which has long been associated with liver damage and allergic reactions such as skin rash.

Researchers at the University of Pittsburgh and Boston’s University’s Slone Epidemiology Center surveyed nearly 14,500 U.S. adults about their use of acetaminophen in the preceding 30 days. The study, which was sponsored by Johnson & Johnson, was conducted over a five-year period, from 2011 to 2016.

Investigators found that 6.3% of acetaminophen users exceeded the recommended maximum adult daily dose of 4,000 mg on at least one day during a week that they used acetaminophen.

Usage patterns grew during the cold and flu season. The odds of taking more than 4,000 mg of acetaminophen increased to 6.5% compared to 5.3% during the off-season.

This was primarily due to increased use of over-the-counter medications designed to treat upper respiratory cold and flu symptoms.


"This is the first multi-year, year-round study that includes detailed data on how consumers used acetaminophen medications," said Saul Shiffman, PhD, of Pinney Associates and the University of Pittsburgh. "The study findings suggest the importance of educating consumers about acetaminophen and counseling them about appropriate use and safe dosages of these medications.

"Getting this message out is especially important during cold/flu season, when people may be more likely to treat illness symptoms with acetaminophen combination products, sometimes without even realizing they contain acetaminophen."

The use of acetaminophen (paracetamol) is even more pronounced in France, according to a new study published in the British Journal of Clinical Pharmacology.

There was a 53% increase in the use of paracetamol in France between 2006 and 2015, and 1000 mg tablets of paracetamol (which are not available in the United States) are now the most-used drug among French adults. There is also a trend towards larger doses. Consumption of 1000 mg tablets increased by 140 percent in France over the ten-year study; while consumption of 500 mg tablets decreased by 20 percent.

Compared to other countries in Europe, France ranked first in paracetamol usage and third in the consumption of mild opioids such as tramadol and codeine. The French use of strong opioids such as morphine was among the lowest in Europe.

"To our knowledge, this is the first published study analysing consumption trends for both non-opioids and opioids over the last decade in France. Long-term surveillance over the past 10 years has highlighted quantitative and qualitative changes in analgesic consumption patterns in France," said study co-author Philippe Cavalié, PhD, of the French National Agency for Medicines and Health Products Safety.

"The very widespread analgesics consumption that we have documented raises the concern of overuse and misuse, as well as addiction to opioids."

The U.S. Food and Drug Administration asked drug makers in 2011 to limit acetaminophen doses to 325 mg per tablet or capsule. The FDA also requires a “Boxed Warning” label – the agency’s strongest warning – to call attention to serious risks.

Over 50 million people in the U.S. use acetaminophen each week for pain and fever – many unaware of the risk of liver injury and allergic reactions. Over 50,000 emergency room visits each year in the U.S. are blamed on acetaminophen overdoses, including 25,000 hospitalizations and 450 deaths.

For more information about acetaminophen and how to avoid overdosing, visit

Do OTC Pain Relievers Dull Your Emotions?

By Pat Anson, Editor

Ibuprofen, acetaminophen and other over-the-counter pain relievers may do more than just dull your physical pain. They could also dull your emotional and cognitive senses, according to a new study.

Researchers at the University of California, Santa Barbara reviewed a small body of clinical studies that suggest OTC pain medications have an overlapping effect on us, both physically and emotionally.

One study, for example, found that acetaminophen makes people feel less empathy for others.

Research also found that women who took ibuprofen reported less social anxiety and hurt feelings after being excluded from a game or when writing about a time when they felt betrayed.

Yet another study found that acetaminophen lessens the discomfort of parting with a prized possession. When asked to set a selling price on an object they owned, individuals who took acetaminophen set prices that were cheaper than the prices set by individuals who took placebos.


"In many ways, the reviewed findings are alarming," wrote lead author Kyle Ratner, PhD, an assistant professor of psychology at UC Santa Barbara. "Consumers assume that when they take an over-the-counter pain medication, it will relieve their physical symptoms, but they do not anticipate broader psychological effects.

“Are more regulations needed? Should warnings be expanded on drug labels? At this point, drawing strong conclusions from the existing studies would be premature. Nonetheless, policymakers might start thinking about potential public health risks and benefits.”

Ratner and his colleagues say one place to start is to further study the effects of OTC analgesics on pregnant women. Recent research has found higher rates of autism and attention deficit disorder (ADHD) in young children whose mothers used acetaminophen while pregnant.

Acetaminophen -- also known as paracetamol – is the world’s most widely used over-the-counter pain reliever. It is the active ingredient in Tylenol, Excedrin, and hundreds of other pain medications. Ibuprofen is also widely used and can be found in brand name products such as Motrin and Advil.   

“Found in medicine cabinets across the world and used multiple times per week by people of all ages, genders, and ethnic backgrounds, these drugs are woven into modern life. Policymakers should take note of existing findings but not rush to judgment,” said Ratner.

The study is published online in the journal Policy Insights from the Behavioral and Brain Sciences.

Pain Relievers Linked to Hearing Loss in Women

By Pat Anson, Editor

Long-term use of acetaminophen and ibuprofen raises the risk of hearing loss in older women, according to a new study published in the American Journal of Epidemiology.

Researchers at Brigham and Women’s Hospital in Boston analyzed data from over 55,000 women between the ages of 48 and 73 enrolled in the Nurses’ Health Study, a long-term study that began in 1976.

They found that about 1 in 6 women who used ibuprofen or acetaminophen for at least six years suffered some degree of hearing loss. No such link was found in the women who used regular doses of aspirin.

“Although the magnitude of higher risk of hearing loss with analgesic use was modest, given how commonly these medications are used, even a small increase in risk could have important health implications,” said senior author Gary Curhan, MD, a physician in the Channing Division of Network Medicine at Brigham and Women’s Hospital.

“Assuming causality, this would mean that approximately 16.2 percent of hearing loss occurring in these women could be due to ibuprofen or acetaminophen use.”

Curhan noted the study was limited to mostly older, white women participating in the Nurses’ Health Study and that further investigation with larger and more diverse populations would be needed to better understand the connection between hearing loss and pain reliever use.

The researchers have previously published findings that indicate high frequency use of non-steroidal anti-inflammatory drugs (NSAIDS) and acetaminophen is associated with hearing loss in men and younger women. High doses of aspirin have also been associated with hearing loss.

The new study did not look at why the medications affect hearing, but previous research suggests the pain relievers affect blood and oxygen flow to sensitive parts of the ear that may compromise hearing.

About two- thirds of women in the U.S. over the age of 60 report some degree of hearing loss.

“Hearing loss is extremely common in the United States and can have a profound impact on quality of life,” said Curhan. “Finding modifiable risk factors could help us identify ways to lower risk before hearing loss begins and slow progression in those with hearing loss.”

Many people wrongly believe that over-the-counter pain relievers are relatively safe because they are available without a prescription. But studies have linked NSAIDs and acetaminophen to cardiovascular disease, hypertension, kidney problems and liver failure.

“I worry that people think NSAIDs and acetaminophen are completely safe, and that they don’t need to think about their potential (side effects),” Curhan told Time.  “But particularly for people who are taking them for chronic pain, I try to encourage them to look at why they are having the pain, not what they can take to try to treat the pain.”

Acetaminophen Linked to Kids’ Behavior Problems

By Pat Anson, Editor

Another study has linked acetaminophen to attention deficit and other behavioral problems in children whose mothers used the over-the-counter pain reliever while pregnant.

"Children exposed to acetaminophen use prenatally are at increased risk of multiple behavioral difficulties,” said lead author Evie Stergiakouli, PhD, of the University of Bristol. “Given the widespread use of acetaminophen among pregnant women, this can have important implications on public health advice.”

The study, published in JAMA Pediatricsinvolved nearly 7,800 mothers in the UK who used acetaminophen in 1991 and 1992.

Prenatal use of acetaminophen in the second and third trimesters was associated with a higher risk of behavior problems and hyperactivity in children. Use of acetaminophen at 32 weeks of pregnancy was also associated with a higher risk for emotional problems.

“We found stronger association between maternal acetaminophen use and multiple behavioral and emotional problem domains during the third trimester than during the second trimester, in agreement with previous studies that have included multiple measurement times during pregnancy," said Stergiakouli

"Given that there is active brain development and growth during the third trimester, this finding could indicate that there are developmental periods when the brain is more sensitive to acetaminophen exposure.” 

Acetaminophen (paracetamol) is one of the most widely used pain relievers in the world. It is the active ingredient in Tylenol, Excedrin, and hundreds of other pain medications. Researchers say over half the pregnant women in the United States and European Union use the drug.

"The risk of not treating fever or pain during pregnancy should be carefully weighed against any potential harm of acetaminophen to the offspring," said Stergiakouli

A recent study of over 2,600 Spanish women linked acetaminophen to autism and attention deficit problems in their children. Studies in Denmark and New Zealand have also linked acetaminophen with a higher risk of hyperkinetic disorders and attention-deficit hyperactivity disorder (ADHD).

Over 50 million people in the U.S. use acetaminophen each week to treat pain and fever. The pain reliever has long been associated with liver injury and allergic reactions such as skin rash.

Acetaminophen Linked to Autism and ADHD

By Pat Anson, Editor

An over-the-counter pain reliever widely used by pregnant women has been linked to autism and attention deficit problems in their children, according to researchers.

In a new study involving over 2,600 Spanish women and their children, published online in the International Journal of Epidemiology, researchers said maternal use of acetaminophen – also known as paracetamol -- appears to increase the risk of autism spectrum disorder (ASD) in boys. There was also a “weak” association between acetaminophen and attention deficit disorder (ADHD) in both male and female children.

“To our knowledge, this is the first prospective study to report an independent association between the use of acetaminophen during pregnancy and autism spectrum symptomatology in exposed children. It is also the first paper to report differential gender effects of prenatal acetaminophen exposure on neurodevelopment,” the researchers said.

About 40 percent of the women in the study used acetaminophen while pregnant. Their children were evaluated at 1 and 5 years of age.

The researchers speculated that boys may metabolize acetaminophen differently than girls, accounting for the greater risk of autism.

“Animal studies have suggested that male mice undergo greater toxicity than female mice after being administered a similar dose of acetaminophen. Furthermore, the male brain may be more vulnerable to early life stressors  and this could explain why neuropsychiatric disorders of childhood, such as ASC and ADHD, are more prevalent in male children,” they said.

Acetaminophen (paracetamol) is the world’s most widely used over-the-counter pain reliever. It is the active ingredient in Tylenol, Excedrin, and hundreds of other pain medications.

In a review of the study, the UK’s National Health Service (NHS) said researchers failed to prove a clear link between maternal use of acetaminophen and autism or ADHD.

“This research cannot prove paracetamol use is directly responsible for these findings. Not all links were statistically significant – for example, paracetamol was not linked with ADHD when looking at full diagnostic criteria, or with ASD when looking at the full sample of children,” the NHS said. “Importantly, no link was found with developmental or intellectual outcomes in the child.

“The current viewpoint is that occasionally using paracetamol as needed, and at recommended doses, is safe during pregnancy. This study has not provided sufficient evidence to the contrary to change this advice.”

Over 50 million people in the U.S. use acetaminophen each week to treat pain and fever. The pain reliever has long been associated with liver injury and allergic reactions such as skin rash.

Another recent study of pregnant women found that Lyrica (pregabalin) – a medication also prescribed for pain – appears to  increase the risk of major births defects, including heart defects and structural problems with the central nervous system.

Does Excedrin Reduce Empathy?

By Pat Anson, Editor

A popular over-the-counter pain reliever may do more than just relieve minor aches and pains. Ohio State researchers say acetaminophen -- the active ingredient in Excedrin and hundreds of other pain medications -- can also make us feel less empathy for the physical and emotional pain of others.

"We don't know why acetaminophen is having these effects, but it is concerning," says Baldwin Way, an assistant professor of psychology at Ohio State’s Wexner Medical Center's Institute for Behavioral Medicine Research.

“Empathy is important. If you are having an argument with your spouse and you just took acetaminophen, this research suggests you might be less understanding of what you did to hurt your spouse's feelings."

Acetaminophen -- also known as paracetamol – is the world’s most widely used over-the-counter pain reliever. The study findings were published in the journal Social Cognitive and Affective Neuroscience.

Way and his colleagues divided 80 college students into two groups, giving half of them a liquid containing 1,000 mg of acetaminophen, while the other half drank a placebo solution that contained no drug. The students didn't know which group they were in.

After waiting an hour for the drug to take effect, the students read eight short scenarios in which someone suffered some sort of physical or emotional pain. For example, one scenario was about a person who suffered a knife wound and another was about a person whose father died. Participants were then asked to rate the pain of each person on a scale ranging from 1 (no pain at all) to 5 (worst possible pain).

Students who took acetaminophen rated the pain of the people in the scenarios to be less severe than those who took the placebo.

"These findings suggest other people's pain doesn't seem as big of a deal to you when you've taken acetaminophen," said Dominik Mischkowski, co-author of the study and a former PhD. student at Ohio State, who is now at the National Institutes of Health.

In a second experiment, students met and socialized with each other briefly. Each participant then watched, alone, an online game that purportedly involved three of the people they just met. In the game, two of the students excluded the third person from the activity.

Participants were then asked to rate how much pain and hurt feelings the students in the game felt, including the one who was excluded.

Results showed that people who took acetaminophen rated the pain and hurt feelings of the excluded student as less severe than the participants who took the placebo.

"Participants had the chance to empathize with the suffering of someone who they thought was going through a socially painful experience," Way said. "Still, those who took acetaminophen showed a reduction in empathy. They weren't as concerned about the rejected person's hurt feelings.

“Because empathy regulates pro-social and anti-social behavior, these drug-induced reductions in empathy raise concerns about the broader social side effects of acetaminophen, which is taken by almost a quarter of U.S. adults each week.”

An earlier Ohio State study found that acetaminophen also dulls emotions.

The pain reliever has long been associated with liver injury and allergic reactions such as skin rash. In the U.S. over 50,000 emergency room visits each year are caused by acetaminophen, including 25,000 hospitalizations and 450 deaths.