Racing with NSAIDs

As the previous poster noted, ibuprofen can cause or contribute to renal failure when used in high doses (greater than 2500mg/day), and the stress of an IM could have potentially made it worse. However, I doubt the leg cramps were related. Those were more likely tied to fitness/energy expenditure during the bike.

As long as you're peeing well now, the ibuprofen shouldn't be an issue. Flexeril, however, is related to tricyclic antidepressants such as amitryptiline and can be fatal if taken well above the recommended dosing (10mg TID)

I do have personal experience racing with NSAIDs at Ironman Canada, The Marathon des Sables, Jordan Telecom Desert Cup and a number of other ultra-distance races.

I do not have medical expertise as I am not a medical expert.

My experience with Aleve during events has been very good. Substantial improvement in comfort, no ill effects. I'l also used aspirin and for me, it does not work as well.

I agree with the above that ibuprofen wasn't related to cramping.  If you don't have renal or dehydration problems and are taking it as directed, NSAIDS shouldn't cause kidney issues either.  I'm a big fan of naproxen sodium for both prophalaxis and treatment of musculoskeletal pain and inflammation. 

However, drugs affect different people differently.  If you think the ibuprofen was the cause of your issues, don't take it.

I used NSAIDs for my first marathon, finished feeling pretty good as I met my goal and my second half was within 2 minutes of my first half.  Later that day though I had kidney pain for a few hours as I rolled around in bed.  I vowed to never use NSAIDs again during a race.

I never heard of NSAIDs causing cramps.  My best guess is that the cramps were simply due to you tackling an unreal course, on what sounded like an unreal day.  Congrats.

Thanks for the input everyone!

And TOM... you've raced the Marathon Des Sables? Nice!
I made the lottery for it in 2013.

Can't be any harder than the St G Ironman... right?   

Disclaimer: Not yet a doctor.

This.  A prof of ours the other day who has been either medical staff or actually running the Boston Marathon for years (he's an anesthesiologist) went over this the other day in class specifically within the context of endurance sports.  Definitely don't take NSAIDS (advil/ibuprofen, Aleve/naproxen, etc) prior or during any endurance event or training.  If you have pain and need something, tylenol is acceptable barring any prior issues you might have with that.  

Note, if you have hypertension and are controlling it with an ace inhibitor or ARB, DEFINITELY don't take NSAIDS, but your doc should have told you that as well.  Same with renal insufficiency within the context of endurance sports etc etc.