Tylenol side effect: Acetaminophen may cause people to take greater risks

COLUMBUS, Ohio — Popping a Tylenol for that nagging headache could do more than just provide some pain relief. A new study finds that taking acetaminophen may also cause an individual to take greater risks than they would otherwise.

Researchers at The Ohio State University conducted a series of experiments to see how the popular pain reliever affects decision making. While we often hear warnings about how acetaminophen can take a dangerous toll on liver, this latest side effect may give thrill-seekers (or risk-averse folks) reason to pause.

In one experiment, researchers had 189 college students (109 men, 79 women) take 1,000 mg of acetaminophen, the suggested dosage for a headache. Some students were unknowingly given a placebo instead of the drug. Once the medication kicked in, participants were provided a list of various events and then rated each one on how risky they thought it was.

Results show that students who’d taken acetaminophen viewed things like “bungee jumping off a tall bridge” or taking skydiving classes as less risky than those given a placebo. Similarly, “speaking your mind about an unpopular issue in a meeting at work,” switching careers in your mid-30s, and walking home alone at night in a high-crime area were also considered less risky by those in the acetaminophen group.

‘They just don’t feel as scared’

“Acetaminophen seems to make people feel less negative emotion when they consider risky activities – they just don’t feel as scared,” explains study co-author Baldwin Way, an associate professor of psychology, in a university release. “With nearly 25 percent of the population in the U.S. taking acetaminophen each week, reduced risk perceptions and increased risk-taking could have important effects on society.”

Another experiment uses a standard risk-taking assessment to see if the results hold true under different circumstances. Once again, 142 students (76 men, 64 women) took either a dose of Tylenol or a placebo. Afterwards, participants completed a computer game in which they get cash rewards for blowing up a balloon without popping it. Students push a button to “inflate” the virtual balloon and receive money as the balloon gets bigger. They can choose to keep blowing up the balloon or stop and collect the reward.

Students given acetaminophen were more likely to press on and risk popping their balloon rather than play it safe and take less cash.

“If you’re risk-averse, you may pump a few times and then decide to cash out because you don’t want the balloon to burst and lose your money,” says Way. “But for those who are on acetaminophen, as the balloon gets bigger, we believe they have less anxiety and less negative emotion about how big the balloon is getting and the possibility of it bursting.”

A third trial involving 215 undergrads (91 men, 122 women) was similar to the balloon experiment. Students also completed standard tests known as the “Columbia Card Task” and the “Iowa Gambling task.” Results once again reveal that the acetaminophen group is more prone to taking greater risks.

Is acetaminophen safe during the coronavirus outbreak?

Way warns that the findings may be more serious than one might realize, especially in today’s climate. That’s because the CDC suggests taking acetaminophen for people experiencing coronavirus symptoms.

“Perhaps someone with mild COVID-19 symptoms may not think it is as risky to leave their house and meet with people if they’re taking acetaminophen,” says Way.

The authors also note that the drug is found in more than 600 medications. It may be wise to check in with your doctor to see if any prescriptions you take contain acetaminophen.

The study is published online in the journal Social Cognitive and Affective Neuroscience.