A Bizarre Side Effect of Taking TylenolWhen you take acetaminophen, the main ingredient in Tylenol, it does more than relieve your pain. The popular medication also reduces your empathy, that is how much you are able to understand the physical and social pain and suffering others feel, according to researchers from The Ohio State University in Columbus.
Acetaminophen is the most common drug ingredient in the United States and is found in more than 600 different medicines, according to the Consumer Healthcare Products Association. Each week about 23 percent of American adults (roughly 52 million people) use a medicine containing acetaminophen.
Led by Baldwin Way, the OSU team conducted two separate experiments.
Experiment No. 1
After waiting one hour for the drug to take effect, the participants read eight short scenarios in which someone suffered some sort of pain. For example, one scenario was about a person who suffered a knife cut that went down to the bone and another was about a person experiencing the death of his father.
Participants rated the pain each person in the scenarios experienced from 1 (no pain at all) to 5 (worst possible pain). They also rated how much the protagonists in the scenarios felt hurt, wounded and pained.
Overall, the participants who took acetaminophen rated the pain of the people in the scenarios to be less severe than did those who took the placebo.
Experiment No. 2
When compared to those who took the placebo, participants who took acetaminophen rated the noise blasts as less unpleasant for themselves--and also thought they would be less unpleasant for others.
In another part of the experiment, participants 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. (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. "Still, those who took acetaminophen showed a reduction in empathy. They weren't as concerned about the rejected person's hurt feelings."
While these results had not been seen before, they make sense in the light of previous research, Way said. A 2004 study scanned the brains of people as they were experiencing pain and while they were imagining other people feeling the same pain. Those results showed that the same part of the brain was activated in both cases.
"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 results were published online in the journal Social Cognitive and Affective Neuroscience.