Paracetamol shown to cause unexpected emotional side effects

If you are taking paracetamol (or acetaminophen in the US) to reduce pain, you might be getting a number of emotional side effects you didn’t plan for.  New evidence shows that people taking the painkiller reported a reduction in empathy or the feeling of pain and suffering over others’ problems.  There has also been reports in a previous study of the blunting of the feelings of joy.

In an earlier study, Way and other colleagues found that acetaminophen also blunts positive emotions like joy.

This latest research, conducted by the Ohio State University were published online in the journal Social Cognitive and Affective Neuroscience as “Acetaminophen can reduce empathy as well as serve as a painkiller.”   It was undertaken in two waves.  The first tested 80 students with a randomised sample, 50% taking 1000mg of acetaminophen and 50% taking a placebo.  After one hour, the students were tested for emotional empathy using eight scenarios.   The participants who took acetaminophen rated the scenarios to be less severe than did those who took the placebo.

In the second phase, 114 students took part in a randomised sample as per the above.  Similar results arose from a deeper set of scenario testing.  One of the scenarios had participants meet and socialise with each other briefly. Each participant then watched, alone, an online game that purportedly involved three of the people they just met. (The other participants weren’t actually involved).

In the “game,” two of the people the participants had met 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 being not as severe as did the participants who took the placebo.

“In this case, the participants had the chance to empathize with the suffering of someone who they thought was going through a socially painful experience,” Way said.

“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 Ph.D. student at Ohio State, now at the National Institutes of Health.

Paracetamol has been one of the dominant pain killers used in Australia since the 1950s.  It comes in a wide range of brands, including Panadol, Herron Paracetamol, Panamax, as well as a wide selection of house brands.

Many other medicines also include paracetamol in them, and its presence is declared on the front of the label.  It is known acetaminophen in the USA, where it is most commonly recognised as the principal ingredient in Tylenol.

Paracetamol is the medicine of choice for people with chronic pain in Australia, according to the TGA.

The recent studies highlighting that changes to emotions can be caused by Paracetamol based medications raises a number of questions about the use of the common medication.

“We don’t know why acetaminophen is having these effects, but it is concerning,” said Way, the senior author of the study.

“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.”

Studies have been showing that paracetamol may reduce the ability to feel others’ pain since 2004.

“In light of those results, it is understandable why using Tylenol to reduce your pain may also reduce your ability to feel other people’s pain as well,” he said.

The same researchers are about to commence another study on another common pain reliever, Ibuprofen to see if it has similar results.

Do you take paracetamol regularly?