March 08, 2018
Researchers who asked more than 14,000 adults about their recent use of acetaminophen found significant numbers are exceeding the maximum adult daily dose of 4 g (4000 mg).
Saul Shiffman, PhD, and colleagues found that the odds of taking more than 4 g of acetaminophen in 1 day increased 24% in the cold/flu season compared with the off-season (6.5% during cold/flu season vs 5.3%).
The overdoses were primarily a result of increased use of over-the-counter combination medications meant to treat upper respiratory cold and flu symptoms. People taking the combination drugs may not even know they contain acetaminophen.
Shiffman, a senior scientific advisor for Pinney Associates in Pittsburgh, Pennsylvania, and professor of psychology, psychiatry, pharmaceutical sciences, and clinical translational research at University of Pittsburgh, and colleagues report their findings in an article published online March 7 in the British Journal of Clinical Pharmacology.
The study included 14,481 US adults who had used acetaminophen in the previous month and were sampled from multiple online research panels between 2011 and 2016. Participants were asked to complete a detailed online daily diary of their medication use for the last 7 days and were not told the study was about acetaminophen.
Researchers found that 6.3% (95% confidence interval [CI], 6.0% - 6.6%) of acetaminophen users exceeded the maximum dose on at least 1 day in the week.
Moreover, the 4-g limit was exceeded on 3.7% of the days participants used medications containing acetaminophen.
Very few users (1.4%; 95% CI, 1.2% - 1.6%) used more than 4 g on 4 or more diary days, and only 0.2%; 95% CI, 0.2% - 0.3%) exceeded 8 g on 4 or more days.
Damage From Overuse
Researchers suggest that more guidance is needed to counsel people on the right dosing of products containing acetaminophen. In high amounts, acetaminophen can cause liver damage.
"This is the first multiyear, year-round study that includes detailed data on how consumers used acetaminophen medications," Shiffman said in a news release.
The authors note that overuse of the medication results in an estimated 112,000 calls a year to poison control centers, 59,000 emergency department visits, and 38,000 hospitalizations.
The average age of participants was 44 years; 61% were women, 24% were nonwhite, 46% reported an income below $50,000, and 82% had post-high school education.
The authors note that the overuse rates represented in the study are from relatively frequent users of acetaminophen and do not represent that of the general population, but they suggest more general education around the medication.
They add, "Our findings suggest that public education campaigns might also include some emphasis on cold/flu season, addressing the use of upper respiratory medications to treat seasonal respiratory illnesses."
This research was sponsored by Johnson & Johnson Consumer, Inc., which markets Tylenol. The authors have disclosed no relevant financial relationships.