Three daily doses of glucosamine and chondroitin may provide the same relief as a smaller dose of prescription celecoxib for people with severe pain from osteoarthritis, according to a randomized trial in four European countries.

In the U.S., glucosamine and chondroitin are available as over-the-counter supplements so their formulations are not regulated like the prescription European version.

“The Europeans have an advantage on us in this regard as glucosamine, chondroitin and the combination are all available as medications,” said Dr. Allen Sawitzke of the Rheumatology Division at the University of Utah in Salt Lake City, a coauthor of the new study.

“As such, their reliable composition and chemistry are more like assured,” he told Reuters Health by email.

The U.S. supplement versions are less reliable in quality and quantity, Sawitzke said.

The new trial included 606 patients over age 40 with moderate to severe pain from knee osteoarthritis living in France, Germany, Poland or Spain.

Osteoarthritis, or wear and tear of the joints, affects more than a third of adults over age 65 in the U.S., according to the Centers for Disease Control and Prevention. There is no cure. Treatments include physical therapy, medication and joint replacement.

The study participants were randomly divided into two groups, one taking a daily combination of 400 milligrams chondroitin sulfate and 500 mg glucosamine hydrochloride (Droglican, made by Bioiberica S.A.). The other group took 200 mg of celecoxib (marketed by Pfizer as Celebrex, Celebra, Onsenal and others) every day.

After six months, both groups had knee pain about half as severe as when they started, and similar reductions in joint swelling and stiffness and increased function, according to results in the Annals of the Rheumatic Diseases.

In U.S. drugstores, a three-month supply of glucosamine and chondroitin supplement costs around $30. Prescription celecoxib, a non-steroidal anti-inflammatory pain reliever, can cost $130 per month, much more expensive than over-the-counter pain relievers, according to Consumer Reports.

Both glucosamine and chondroitin are available by prescription in Europe, but some advise against using them for osteoarthritis due to lack of evidence, the authors note.

But the new study suggests that in combination they can be effective for osteoarthritis patients, especially for people with heart or gastrointestinal problems who may not be able to take an NSAID like celecoxib, the authors write.

Celecoxib can cause serious side effects like high fever, noted coauthor Dr. Yves Henrotin, head of the Bone and Cartilage Research Unit at the University of Liège in Belgium. It can also cause ulcers and bleeding, according to the National Institutes of Health.

“My recommendation is to consider a patient’s (other diseases) before treatment,” Henrotin told Reuters Health by phone.

“For countries where the prescription preparations are available, the combination of glucosamine and chondroitin sulfate appears to be as effective and at least as safe so might be the preferred way to start,” Sawitzke said. It may be considered in other countries as well, but will have to be monitored closely through the first months of use, he said.

However, the prescription glucosamine and chondroitin formulation in this European study cannot be generalized to the dietary supplement versions available in the U.S. and U.K., they emphasize.

“I think many U.S. providers have quit recommending a trial of the glucosamine and chondroitin to patients affected by osteoarthritis as strong support was not available,” Sawitzke said. “In distinction, the European market has remained strong and the guidelines actually recommend their use.”

“We still have to consider financial constraints, a given patient's adverse events risks, and the risks of the unknown in the over-the-counter market,” he said.