Common Pain Meds Could Be Contributing To Antibiotic Resistance

Common over-the counter painkillers might be quietly fueling antibiotic resistance, a new study warns.

Ibuprofen and acetaminophen appear to enhance mutations in E. coli, making the common bacteria more resistant to the broad-spectrum antibiotic ciprofloxacin, researchers reported in the journal npj Antimicrobials and Resistance.

What’s more, the two drugs amplify this effect when used together, researchers found.

“Antibiotic resistance isn’t just about antibiotics anymore,” said lead researcher Rietie Venter, an associate professor with the University of South Australia.

“This study is a clear reminder that we need to carefully consider the risks of using multiple medications – particularly in aged care where residents are often prescribed a mix of long-term treatments,” she said in a news release.

The World Health Organization (WHO) has declared antibiotic resistance a threat to public health, researchers said in background notes.

In the United States, more than 2.8 million antimicrobial-resistant infections occur each year, and more than 35,000 people die as a result, says the U.S. Centers for Disease Control and Prevention (CDC).

“Antibiotics have long been vital in treating infectious diseases, but their widespread overuse and misuse have driven a global rise in antibiotic-resistant bacteria,” Venter said.

“This is especially prevalent in residential aged care facilities, where older people are more likely to be prescribed multiple medications — not just antibiotics, but also drugs for pain, sleep or blood pressure — making it an ideal breeding ground for gut bacteria to become resistant to antibiotics,” she said.

For the new study, researchers performed lab experiments on nine drugs commonly used in nursing homes, including ibuprofen (Advil) and acetaminophen (Tylenol).

E. coli strains were exposed to the drugs and ciprofloxacin, to see whether the non-antibiotic drugs influenced the ability of the bacteria to resist the antibiotic.

E. coli causes gut and urinary tract infections, researchers noted. Infections can cause watery diarrhea that’s sometimes bloody, nausea, vomiting, stomach pain and cramps.

“When bacteria were exposed to ciprofloxacin alongside ibuprofen and paracetamol, they developed more genetic mutations than with the antibiotic alone, helping them grow faster and become highly resistant,” Venter said.

“Worryingly, the bacteria were not only resistant to the antibiotic ciprofloxacin, but increased resistance was also observed to multiple other antibiotics from different classes,” she added.

Researchers also think they’ve figured out the genetic mechanisms behind the antibiotic resistance.

Ibuprofen and acetaminophen both appear to activate E. coli’s ability to expel antibiotics, rendering the drugs less effective, Venter said.

In fact, by improving the bacteria’s ability to resist antibiotics, the painkillers actually provide it more time to mutate into even more resistant forms, researchers said in their paper.

More research is needed to confirm these drug interactions, and to gain more awareness of how common medications might be contributing to antibiotic resistance, the researchers said.

“This doesn’t mean we should stop using these medications, but we do need to be more mindful about how they interact with antibiotics – and that includes looking beyond just two-drug combinations,” Venter said.

More information

The U.S. Centers for Disease Control and Prevention has more on antimicrobial resistance.

SOURCE: University of South Australia, news release, Aug. 25, 2025

Source: HealthDay