NSAIDs Somewhat Better Than Tylenol for Osteoarthritis
Although everyday acetaminophen reduces pain from osteoarthritis of the hip or knee, people with moderate to severe pain do better on non-steroidal anti-inflammatory drugs, a new review of previous studies concluded.
The review comprised 15 studies involving 5,986 participants. Seven of the trials compared acetaminophen (sold as Tylenol) to placebo and 10 compared acetaminophen to NSAIDs. Studies looked at the traditional NSAIDs such as ibuprofen (sold as Advil, Nuprin, Haltran, Medipren, Motrin, Midol, Brufen and Genpril), diclofenac (sold as Cataflam, Voltaren and Voltaren-XR), a combination of diclofenac and misoprostol (sold as Arthrotec) and naproxen (sold as Aleve).
The studies under review also included two drugs from the relatively new class of NSAIDs known as Cox-2 inhibitors, celecoxib (sold as Celebrex) and rofecoxib (which was once sold as Vioxx and is no longer on the market). Aspirin was not included in the studies.
The review, led by Tanveer Towheed of Queens University in Ontario, appears in the new issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
Acetaminophen showed superior effectiveness compared to placebo for reducing osteoarthritis-related pain. But when compared to NSAIDs, acetaminophen was less effective. On a scale of 0-100, pain decreased 4 more points for patients who took acetaminophen versus those who took a fake pill, and pain decreased 6 more points among those who took NSAIDs instead of acetaminophen.
"There does not appear to be a major difference in side effects between acetaminophen and NSAIDs, although people taking traditional NSAIDs were more likely to have stomach problems," the researcher said. They found that 19 percent of patients in the NSAID group versus 13 percent in the acetaminophen group experienced gastrointestinal side effects.
On average, the trials examined lasted only six weeks, making it difficult to arrive at a solid conclusion about adverse effects, and the authors recommend that decisions be made on the basis of patient preference, individual risk factors, cost, availability of the drugs and the doctors' judgment.
Osteoarthritis is the most common form of arthritis. An estimated 12.1 percent of Americans age 25 and older show signs and symptoms of osteoarthritis. About 6 percent of Americans who are 30 and over will develop osteoarthritis of the knee, and about 3 percent will develop osteoarthritis of the hip.
The authors note that the guidelines for treatment and the opinions of osteoarthritis experts are not uniform in their recommendations of acetaminophen and non-steroidal anti-inflammatory drugs as first-line treatments.
Guidelines from the American College of Rheumatology recommend acetaminophen as initial therapy in patients with mild to moderate osteoarthritis pain. However, for patients with moderate to severe pain, NSAIDs are suggested as an alternative initial therapeutic approach.
Canadian guidelines recommend NSAIDs as the drug of choice for treatment of moderate to severe osteoarthritis, suggesting acetaminophen as first-line treatment for patients with mild pain.
"There was a statistically significant improvement in patients' arthritis pain and function in patients taking acetaminophen compared to placebo, but it is unclear if this of clinical significance," said Scott Zashin, M.D., author of a book on arthritis pain and assistant clinical professor at University of Texas Southwestern Medical School. "In other words, patients did better on the acetaminophen but it was not by much."