The current view in ultra-running circles is that NSAID and the slight dehydration often present in long runs make the risk of rhabdomyolysis too high - hence they are normally not taken.
It used to be the ibuprofen was so commonly taken that it was called Vitamin I. Aid stations would have bowls full of them for runners to take.
In an email to the ultra list, Jennifer Jurynec said:
The problem, as I understand it, with NSAID use is not one of directly causing
rhabdomyolysis. Rhabdomyolysis in runners is a consequence of insufficient
energy to meet excessive demands with resultant muscle damage that causes a leak
of myoglobin ( in addition to other intracellular components) into the blood.
Myoglobin, in particular, can have multiple deleterious effects on the kidneys
and lead to renal failure if profound enough.
The issue with NSAID's is that they inhibit both cox1 and cox2 pathyways. These
pathyways, among other things, are involved with making prostaglandins.
Prostaglandins are important for preserving renal artery blood flow.
Prostaglandins, under normal conditions, are present in low amounts and are
therefore, not the primary thing regulating kidney perfusion. Where they become
more important is when either disease is present or the normal kidney milieu is
disputed by transient factors. These factors can be DEHYDRATION and electrolyte
balance among others.
My opinion is that there are multiple insults to kidneys that fail following an
ultrarace. They probably include, rhabdomyolysis, decreased renal perfusion from
nsaid use AND dehydration and electrolyte imbalances. I think they all combine
to form an unfavorable situation resulting in renal failure. NSAID's in
isolation would not cause renal problems unless you have underlying kidney
disease or some physical state that results in decreased renal perfusion (such
as heart failure).
There are examples of athletes getting rhabdomyolysis such as Erik Skaggs or Don Davis.
However, there are some studies that show that NSAIDs may be protective of the kidneys.