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Not long ago, I took ibuprofen after a dental procedure and was amazed at how well it worked. Millions of people have had similar experiences with ibuprofen and related medications (called non-steroidal anti-inflammatory drugs, or NSAIDs) when used for a number of conditions, including arthritis, back pain, and headache. That's why NSAIDs are among the most commonly prescribed drugs worldwide.
More than a dozen different NSAIDs are available, including naproxen (as in Naprosyn or Aleve), celecoxib (Celebrex), diclofenac (Voltaren) and indomethacin (Indocin). Aspirin is also an NSAID, though it is usually taken in small doses for its blood thinning effects (to prevent heart attack or stroke) rather than for pain.
NSAIDs are fairly safe, but not risk free
The safety profile of NSAIDs is generally quite good, especially when taken in small doses for short periods of time. That's why several of them, including ibuprofen and naproxen, are available in low doses over the counter in this country and elsewhere.
However, as is true for any drug, NSAIDs can cause trouble. Upset stomach, intestinal bleeding, and cardiovascular problems are among the most important and widely recognized side effects. But, the list is longer than that. The risk of heart attack may be increased among users of NSAIDs, especially among those at increased risk (such as those who have had a previous heart attack). Another important item on that longer list is kidney injury. Most of the time, NSAID-related kidney problems develop in people who already have kidney disease or who take other medications that can affect kidney function. High doses and prolonged use are also risk factors.
A new study of NSAID use during exercise
NSAID use is common among people who deal with aches and pain during and after exercise. In fact, many marathoners and other endurance athletes take NSAIDs preventively to reduce pain and possibly improve performance. However, these same athletes are at particular risk for kidney injury. Dehydration and muscle damage are common among endurance athletes and can also contribute to kidney injury. If NSAIDs are added to the mix, might these athletes be at even higher risk for kidney damage? Should they avoid using NSAIDs? That's the subject of a new study published in the July 2017 edition of Emergency Medicine Journal.
Researchers divided 89 ultramarathoners participating in one of several seven-day, 155-mile races into two groups: one group took 400 mg of ibuprofen (equivalent to two over-the-counter Advil) every four hours for three or four doses toward the end of the race. The other group took a placebo.
What they found was concerning:
- Kidney injury was quite common. About 44% of these ultramarathoners experienced significantly reduced kidney function by the end of the race.
- Kidney injury was more common among those taking ibuprofen. Just over half of the NSAID-takers had reduced kidney function, while about one-third of those in the placebo group did. Despite these findings, the differences in rates of kidney injury were not statistically significant.
- The severity of kidney injury was greater in the ibuprofen group.
- A faster finish and greater weight loss during the race (likely due to greater dehydration) increased the likelihood of kidney injury.
Most of us will never attempt to run 155 miles in one week, so the results of this study may not apply to a more typically exercising adult. In addition, the study was quite small, which limits its ability to detect significant differences between the two groups. Had the same differences in the rates of kidney disease been observed in a much larger study, the findings would likely have been statistically significant. And, this study did not examine the long-term effects of ibuprofen on kidney function. It's possible (or perhaps likely) that with rest, hydration, and time, the kidney function of athletes with kidney injury in this study returned to normal with no permanent detrimental effects. Finally, higher or lower doses of ibuprofen may have produced different results.
Still, this study raises some serious concerns about the wisdom of taking ibuprofen during exercise, at least among endurance athletes. The authors of this study suggest acetaminophen (as in Tylenol and other products) as an alternative, but we'll need more research to know whether other alternatives are truly safer.
The bottom line
If you are taking an NSAID regularly, you should be having regular blood monitoring, including measures of kidney function. And if you have significant kidney disease, you should probably avoid non-aspirin NSAIDs altogether. Ask your doctor whether you are a good candidate for NSAID use. They can be quite helpful, and many of their side effects can be avoided with proper precautions.