WEDNESDAY, DECEMBER 10, 2025 (HealthDay News) — Taking opioids may increase the risk that some patients will develop a dangerous infection, new research shows.
The infection is called Clostridioides difficile or C. diff. It affects the large intestine and can spread easily, especially in hospitals and nursing homes. The illness can cause severe diarrhea, stomach pain, nausea and vomiting. In severe cases, life-threatening complications can occur.
According to the data, about 500,000 Americans get C. diff each year.
Researchers at the University of Georgia analyzed data from nearly 120,000 patients in four studies. They found that about 31% of people who took opioids developed C. diff, compared to 17% of those who did not take opioids.
“There is mixed evidence on the association between these drugs and C. diff,” study co-author Lorenzo Villa-Zapata, an associate professor of pharmacy, said in a news release. “For us, the main thing is to provide evidence that doctors can use to assess benefits and side effects when prescribing medications.”
Opioids are often used to treat pain, especially after surgery or injury.
However, previous research shows that opioids can weaken the immune system and destroy healthy bacteria in the gut. These changes can promote the growth of harmful bacteria like C. diff.
“Opioids alter the gut microbiome, creating an environment more conducive to colonization by C. diff,” explained lead author Pooja Gokhale, a doctoral student in pharmacy. “And because opioids can cause immunosuppression, you’re generally more susceptible to infection, and of course C. diff is a highly infectious disease.”
However, researchers emphasized that opioids may still be the right option for some patients.
“It has to be decided on a case-by-case basis. Every patient has a completely different story,” Gokhale said. “If it’s a healthy young patient, doctors may not be as concerned about the risk, but hospitalized or immunocompromised patients are already at high risk.”
The results were recently published in the American Journal of Infection Control.
More information
The Mayo Clinic has more information about C. difficile.
SOURCE: University of Georgia press release, December 8, 2025
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