More commonly known as Prozac, the drug may protect against infections by boosting immune response and reducing inflammation,
Antidepressants have long been used to manage mental health conditions, but new research is showing they might do more than just regulate mood. Scientists at the Salk Institute have uncovered an unexpected benefit of fluoxetine, commonly known as Prozac: it helps protect the body from serious infections, including sepsis. This discovery could open the door to new ways of treating life-threatening infections, potentially giving doctors a new tool in their fight against disease.
Sepsis is a dangerous condition where the body’s response to infection spirals out of control, leading to widespread inflammation, organ failure, and often death. While antibiotics can kill the bacteria causing the infection, they don’t necessarily stop the body’s overreaction. That’s where fluoxetine comes in. Researchers found that this widely used antidepressant doesn’t just fight bacteria—it also helps the body manage its immune response, reducing the risk of severe complications.
This discovery builds on previous studies suggesting that people taking selective serotonin reuptake inhibitors (SSRIs), like fluoxetine, had less severe COVID-19 symptoms. Researchers at Salk wanted to understand why. Their experiments with mice revealed that fluoxetine helped control inflammation while also reducing bacterial growth. Mice given fluoxetine before infection were less likely to develop sepsis, and those that did had better survival rates. This suggests the drug is doing more than just treating depression—it’s helping the body defend itself against infections.
One of the key findings was fluoxetine’s ability to increase levels of IL-10, a molecule that helps keep inflammation in check. Infections often cause a surge of inflammatory molecules, which, if left unchecked, can damage tissues and organs. IL-10 helps counteract this, preventing excessive damage while still allowing the immune system to fight off the infection. Researchers also discovered that fluoxetine helped keep triglyceride levels stable, which is important for maintaining heart health during an infection.
Another surprising discovery was that fluoxetine’s infection-fighting properties worked independently of its effects on serotonin, the brain chemical it’s known for regulating. To test this, researchers compared two groups of mice: one with normal serotonin levels and another where serotonin was blocked. Both groups still benefited from fluoxetine’s protective effects, showing that its immune benefits are unrelated to its role as an antidepressant. This opens the possibility that other SSRIs might have similar infection-fighting properties, leading researchers to explore further.
While these findings are promising, scientists are now looking at how fluoxetine might be used to treat infections in people. The next steps include determining the right dosage for treating sepsis and seeing if other antidepressants have similar effects. Since fluoxetine is already widely used and considered safe, repurposing it for infection treatment could happen much faster than developing an entirely new drug.
This research highlights how medications originally designed for one purpose can have unexpected benefits in other areas. Fluoxetine has been on the market for decades, but only now are researchers uncovering its potential to help the body fight infections. As scientists continue exploring this connection, fluoxetine could become more than just a mental health treatment—it could be a life-saving tool in the fight against deadly infections.
Sources:
Prozac’s surprising immune-boosting effects could lead to new treatments for sepsis
Fluoxetine promotes IL-10–dependent metabolic defenses to protect from sepsis-induced lethality
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