• Posted May 2, 2025

Common Diabetes Drug Effective Against Knee Arthritis Pain

A common diabetes drug can be repurposed to help overweight and obese people with knee arthritis, a new study says.

Metformin reduced knee arthritis pain during a six-month treatment period, potentially delaying the need for knee replacement surgery, researchers reported recently in the Journal of the American Medical Association.

“Metformin works in a number of ways on the knee, including affecting low-grade inflammation and other metabolic pathways that are important in knee osteoarthritis,” senior researcher Flavia Cicuttini, a professor of health systems services and policy at Monash University in Australia, said in a news release. “It is a different way to treat knee osteoarthritis pain.”

Metformin is commonly prescribed to help lower blood sugar levels in people with type 2 diabetes. It reduces sugar absorption from the intestines, lowers glucose production in the liver, and improves insulin sensitivity, according to Drugs.com.

For this study, researchers recruited 107 overweight or obese people with knee pain and randomly assigned about half to take metformin pills and the rest a placebo.

The metformin group reported a 31-point reduction in pain after six months, compared with a 19-point reduction for the placebo group.

The results show that metformin is a potentially new and affordable way to improve knee pain from arthritis, Cicuttini said.

Today, people are asked to exercise and lose weight to reduce knee pain, which many find hard to do, Cicuttini said.

Other options like acetaminophen, non-steroidal anti-inflammatory drugs and topical creams tend to have small benefits, she added.

As a result, people tend to seek knee replacement surgery as soon as possible when arthritis pain becomes unbearable.

“At first glance this may seem reasonable, but it is a major problem because patient dissatisfaction with knee replacements is already high at between 20 to 30%, even when the operation is technically perfect,” Cicuttini said.

And dissatisfaction rates are highest when the operation is done for early knee osteoarthritis, she said.

“To go through the effort and cost of a big operation like a knee replacement, only to be unhappy with the results because of ongoing pain and symptoms, is definitely low-quality care," Cicuttini said. "Doing a knee replacement earlier also increases the potential need for the procedure to be redone.”

She argued that doctors "are very familiar with metformin, which is a low-cost, safe medication," adding that it has the potential to delay people having knee replacements before they are absolutely needed.

“If people on metformin have less knee pain and are able to do more physical activity, then knee replacements can wait,” Cicuttini concluded.

However, she noted that larger studies are needed to confirm the drug’s benefits.

“Because of the modest sample size, confirmation in a larger clinical trial is warranted,” Cicuttini said of her study.

More information

The Cleveland Clinic has more about knee arthritis.

SOURCE: Monash University, news release, April 30, 2025