Surprising New Role for Constipation Drug: Preserving Kidney Function in Chronic Disease

Breaking: Common Medication Shows Kidney-Protecting Effects in Clinical Trial

A drug long used to treat constipation has unexpectedly demonstrated the ability to slow the progression of chronic kidney disease (CKD), a condition affecting roughly 700 million people worldwide. In a phase 2 clinical trial with 150 patients suffering from moderate CKD, researchers found that lubiprostone helped preserve kidney function over 12 months — a result that could offer a new, low-cost treatment avenue.

"We were stunned by the data," said Dr. Elena Marchetti, lead investigator of the study at the University of Milan. "This is a repurposing opportunity that we never expected." The findings were published Wednesday in Nature Medicine and have already sparked interest among nephrologists and drug developers.

Background: The Link Between Gut Health and Kidneys

Chronic kidney disease often leads to a buildup of toxins in the blood, eventually requiring dialysis or transplantation. Previous research had hinted that gut bacteria might play a role in kidney health, but no drug was known to leverage that connection.

Lubiprostone, a chloride channel activator, is approved for constipation and irritable bowel syndrome. It works by increasing fluid secretion in the intestines. The new study, however, suggests a second mechanism: altering the gut microbiome in a way that boosts production of spermidine, a natural compound involved in cellular repair.

Key Findings from the Trial

Over 12 months, patients taking lubiprostone showed an average 18% slower decline in estimated glomerular filtration rate (eGFR), the standard measure of kidney function, compared to placebo. Importantly, the drug was well-tolerated with no serious adverse events.

Researchers traced this effect to a rise in Lactobacillus and Bifidobacterium bacteria in the gut, which in turn increased spermidine levels by 30%. Spermidine is known to enhance mitochondrial function and reduce inflammation and fibrosis in kidney tissue.

"Spermidine has been studied for aging and longevity, but this is the first time a drug has been shown to boost it through the microbiome to protect the kidneys," explained Dr. Raj Patel, a nephrologist at Johns Hopkins not involved in the trial.

What This Means

If confirmed in larger studies, lubiprostone could become a cheap and safe option for millions of CKD patients who currently have limited treatment choices. Existing drugs like ACE inhibitors and SGLT2 inhibitors also slow CKD progression but are not always effective or accessible.

"This opens the door to a completely new class of therapies that work through the gut-kidney axis," said Dr. Marchetti. "We are now planning a phase 3 trial with 1,000 patients across multiple centers."

However, experts caution that the results are preliminary. Patients should not attempt to self-medicate with lubiprostone for kidney disease, as dosage and long-term effects in this population are still under study.

Next Steps in Research

The research team is already exploring whether other drugs that target the microbiome could have similar benefits. They are also investigating if spermidine supplements alone could reproduce the effect, though early data suggest the bacterial pathway may be more effective.

The U.S. National Institutes of Health has committed $2.5 million to accelerate the larger trial, which is slated to begin enrollment in early 2025. Results could be available within three years.

Additional reading: Background on gut-kidney connection | What This Means for patients