Rheumatoid arthritis treatment includes disease-modifying arthritis medications, but osteoarthritis, which is more common and involves wear and tear on joints, has no drug that slows down the disease’s progression. However, researchers continue to develop and study potential disease-modifying osteoarthritis drugs.
Interestingly, one of the “newest” drugs for arthritis pain under study may be an old standby used to treat type 2 diabetes: metformin. The drug is showing some promise as an osteoarthritis treatment by reducing pain and potentially offering joint protection
Developing a medication that effectively treats the osteoarthritis disease process “is almost the holy grail of arthritis research since osteoarthritis really overwhelms in volume any other type of arthritis we see,” says Chad Deal, a Cleveland, Ohio, rheumatologist. “It’s a big disappointment that we have all these disease-modifying arthritis medications for rheumatoid arthritis, and we have none for osteoarthritis, which is the most common cause of disability in arthritis patients. People end up needing pain management and then getting joint replacements.”
Multiuse Metformin
The U.S. Food and Drug Administration (FDA) originally approved metformin in the 1990s to treat type 2 diabetes, and it now has several “off-label” uses for other conditions (see sidebar).
Available by prescription, metformin aids in blood sugar control by helping the body respond to the insulin it makes naturally, decreasing the sugar the liver makes and reducing the sugar absorbed in the intestines.
Side effects are generally mild, but diarrhea and vomiting may affect up to 30 percent of people taking metformin. It carries a black box warning for a rare side effect of lowering the acidity of the blood, which can be fatal and is more likely to occur in people with liver or kidney impairment, alcoholism, advanced age and other factors. People taking metformin need to be followed by a health-care professional.
A Potential New Arthritis Medication?
In a 2014 study, researchers reported that use of metformin plus meloxicam, a prescription nonsteroidal anti-inflammatory drug (NSAID), was associated with a 25 percent reduction in total joint replacements, compared with use of an NSAID alone.
More recently, a 2025 study involving people with knee osteoarthritis pain and overweight or obesity showed a reduction in knee pain at six months for those taking metformin versus a placebo, but not at three months.
Anti-inflammatory meds are a cornerstone of arthritis treatment. Preliminary studies in animals and humans suggest that metformin might reduce inflammation, as well as preserve cartilage and improve osteoarthritis pain. Pain management is a critical part of treating osteoarthritis and often the primary outcome of human osteoarthritis studies.
Some studies of people with diabetes have shown a reduction in total joint replacements for those taking metformin. Combined with data from some animal studies, this evidence is giving researchers and clinicians some hope that metformin might be an effective osteoarthritis treatment, especially if used early in the disease process.
“The key to using this drug is probably using it early, before you have even mild to moderate disease,” Dr. Deal says. An ongoing study is investigating metformin use after injuries such as ligament ruptures to prevent osteoarthritis.
Drug Repurposing Can Be Slow
The good news is that metformin is available as a relatively inexpensive generic formulation, often costing $20 to $50 per month without insurance. Repurposing approved medications has potential for improving health more quickly because the medications have already been through the years of safety trials required for FDA approval.
On the downside, generic medications under investigation for repurposing for another condition have limited investment from pharmaceutical companies, and this slows research and FDA approval for new uses. Although FDA-approved drugs can be prescribed off label for other conditions, insurance often does not cover these off-label uses.
Is Metformin One of the Newest Drugs for Arthritis Pain?
Overall, cautious optimism is warranted that repurposing metformin may improve pain from osteoarthritis and reduce the need for total joint replacement surgeries. Despite the positive study findings, the evidence is not yet strong enough to justify routine prescribing of metformin for osteoarthritis alone, Dr. Deal notes.
“I don’t think you will find anybody prescribing metformin for osteoarthritis outside a study right now,” he adds, “but I think the recent studies of metformin for osteoarthritis are intriguing.”
