Two of the world’s most common painkillers—ibuprofen and acetaminophen (also known as paracetamol)—may be quietly making one of our biggest health threats worse: antibiotic resistance.
A new study from the University of South Australia, published in npj Antimicrobials and Resistance, has revealed that these everyday medicines don’t just help relieve pain and fever—they can also push bacteria to become resistant to antibiotics.
Even more concerning, when ibuprofen and acetaminophen are used together, they appear to amplify the effect, driving antibiotic resistance to even higher levels.
The research looked at how non-antibiotic medicines interact with ciprofloxacin, a broad-spectrum antibiotic used to treat skin, gut, and urinary tract infections, and with Escherichia coli (E. coli), a common bacterium often behind these infections.
When E. coli was exposed to ciprofloxacin along with ibuprofen and acetaminophen, the bacteria developed more genetic mutations than with the antibiotic alone.
These changes allowed the bacteria to grow faster and become much more resistant—not only to ciprofloxacin, but to several other classes of antibiotics as well.
This discovery has serious health implications, especially for older people in residential aged care homes, where multiple medications are commonly prescribed.
Antibiotics are often given in these settings, but so are drugs for pain, sleep problems, high blood pressure, and diabetes. According to the researchers, this mix of medications creates an environment where gut bacteria can adapt and become resistant.
Antibiotic resistance is already a global crisis. The World Health Organization has called it one of the greatest threats to human health, with resistant bacteria directly responsible for 1.27 million deaths worldwide in 2019.
Antibiotics have been lifesaving for decades, but overuse and misuse have accelerated the rise of bacteria that can no longer be killed by them. This study shows that the problem may be even more complex than previously thought, because non-antibiotic drugs may also play a role.
Lead researcher Associate Professor Rietie Venter explained that the team not only observed the resistance but also uncovered the mechanisms behind it. Both ibuprofen and acetaminophen activated bacterial defense systems, helping the microbes pump out antibiotics before they could take effect.
The study also looked at other medications often prescribed in aged care, including diclofenac, furosemide, metformin, atorvastatin, tramadol, temazepam, and pseudoephedrine. While the strongest effects were seen with ibuprofen and acetaminophen, the findings suggest that many non-antibiotic drugs could influence how bacteria respond to antibiotics.
The researchers stress that this doesn’t mean people should stop using painkillers, but it does mean we need to be more cautious about how multiple medications are combined, particularly in vulnerable groups such as older adults.
They are calling for further studies to explore how common medications may interact with antibiotics, so that doctors can make safer, more informed decisions about long-term treatments.
In the fight against antibiotic resistance, it seems the solution may not be as simple as just limiting antibiotics themselves—we may also need to look closely at the everyday drugs we often take alongside them.
If you care about pain, please read studies about how to manage your back pain, and Krill oil could improve muscle health in older people.
For more health information, please see recent studies about how to live pain-free with arthritis, and results showing common native American plant may help reduce diarrhea and pain.
Source: University of South Australia.
