People who take ibuprofen two or more times a week are considerably less likely to develop Parkinson's disease than those who don't take the drug, according to a study published online March 2 in the journal Neurology.
The finding suggests this common over-the-counter painkiller (sold under brand names that include Advil, Motrin and Nuprin) may actually protect the brain against the degeneration that produces the symptoms of Parkinson's, including shaking, muscle stiffness and other difficulties with movement and coordination.
But lead author Xiang Gao, M.D., of Harvard Medical School and School of Public Health, says more research is needed to confirm a cause-and-effect link and to understand how the effect works before doctors should consider recommending ibuprofen to slow or prevent Parkinson's.
Who is at risk?
James Beck, director of research programs at the Parkinson's Disease Foundation, concurs. "I think this is real," he adds. "I think there is something associated with how ibuprofen works in the body which may play a role in Parkinson's. This study acts like a compass that will guide the basic research in the right direction.
"Parkinson's disease involves the death of cells in the midbrain responsible for producing dopamine, a key chemical signaler. Its cause is not well understood, but genetic vulnerability, perhaps coupled with exposure to environmental toxins, seems to play an important role. Parkinson's tends to strike around age 60, and the risk increases with age.
Substantially more men than women develop the disease.
The latest analysis examined health and medical reports from a study group of 98,892 female nurses and a group of 37,305 male health professionals, following them for six years beginning in 2000. Those who took ibuprofen regularly had a 38 percent lower risk of ending up among the 291 patients diagnosed with Parkinson's during that time. The likelihood of getting Parkinson's dropped with increasing weekly doses of ibuprofen.
In addition, the researchers performed a statistical analysis joining their study with six others looking at painkillers like ibuprofen and Parkinson's disease risk. Taking the studies together, the researchers found a slightly smaller but still substantial 27 percent reduction in Parkinson's risk among those taking ibuprofen.
Painkillers and Parkinson's
For years scientists have suspected that painkillers in a class called nonsteroidal anti-inflammatory drugs (NSAIDs), a group that includes ibuprofen, aspirin and naproxen, protect the brain from the damage associated with diseases such as Parkinson's and Alzheimer's by controlling inflammation. But a 2005 paper by Gao's coinvestigators and a 2009 analysis by another group have suggested the association with Parkinson's does not apply to the entire drug class. This new study sharpens the point; it found no reduction in Parkinson's risk for NSAIDs other than ibuprofen, suggesting, the authors write, "that ibuprofen has potential neuroprotective effects not shared by aspirin or other commonly used analgesics."
The investigators speculate this distinction could be due to ibuprofen's special ability to act on a particular signaling pathway in the brain that involves inflammation, the accumulation of destructive molecules called free radicals, and programmed cell death.
Not ready for prime time
An accompanying editorial says doctors should "absolutely not" begin prescribing ibuprofen for patients with Parkinson's disease. Why? Because it may be that ibuprofen protects against the "initial insult" that leads to Parkinson's but is useless once symptoms appear, or it may be it's not ibuprofen at all but some separate characteristic of ibuprofen users that actually protects against the condition, explains the lead editorialist, James H. Bower, M.D., associate professor of neurology at the Mayo Clinic in Rochester, Minn. Meanwhile, he says, long-term ibuprofen use comes with the risk of serious side effects. These include irritation and stomach bleeding and increased risk of heart and kidney problems.
In his editorial, Bower compares the findings on ibuprofen to similar observational findings on smoking, caffeine consumption and high blood levels of uric acid, all of which have been associated with lower risk of Parkinson's. Rather than suggest people try these approaches, he says, scientists have incorporated them into research that tests their effect in a safe form and controlled environment.
Mya Schiess, M.D., director of movement disorders and neurodegenerative diseases at the University of Texas Medical School at Houston, says she has followed research on the issue closely, and does recommend ibuprofen for patients who have a sharply increased risk of developing Parkinson's — for example, those with a rare and disruptive problem called rapid eye movement (REM) sleep behavior disorder, in which they act out their dreams.
Schiess says although she screens patients for problems that could make ibuprofen riskier, and watches them for side effects, the amount linked to reduced risk for Parkinson's is generally not dangerous. "This study is based on whether people use ibuprofen a minimum of two times a week, and that's not an excessive amount of medicine," she says. "It's not a daily, scheduled amount of medicine. I would think that that has to be strongly taken into consideration."
Katharine Greider lives in New York and writes about health issues.