I am NOT seeking medical advice, but only analysis of something I did that may have near killed me. 
Starting last Saturday, I began feeling weak and achy. For no explicable reason. I weigh 110 kg (243 pounds.) For this I started taking 1200 mg of buprofen every 4 hours. 800 mg is the max prescription dose, and to adjust for my weight I took 1,200 mg. I have taken doses like this (occasionally, not chronically) for almost 20 years for nasty pain, with little problems. This isn’t that astronomical because I am well overweight. Although less overweight than I thought. I hadn’t realized how much weight I had lost, due to overeating less, in the last couple years. I thought my weight was more like the previous 140 kg. More than twice the average of 65 kg for an adult male.
Due to stress of the pain, I was having excess stomach acid production. For that I also took at this time the antacid caclium carbontate (“Tums”) at fairly hefty doses. Calcium carbonate tends to be VERY safe:
http://www.camd.lsu.edu/msds/c/calcium_carbonate.htm
LD50 : 6450 mg/kg (oral, rat)
That is astronomical.
The pain and weakness got increasingly worse, and unbearable. On Tuesday around noon, even though I am quite poor and as such usually have no contact with doctors at all, I went to a hospital ER. I was seriously worried about my health.
They put me on an IV saline drip, hooked up to an EKG, numerous blood samples taken, and such. The ER folks saw this as all kinds of serious. I was hoping for a quick in and out, maybe some pain killers prescribed, etc, and then be sent quickly home. I was diagnosed with acute renal failure. I was inclined just to check out late in the evening, even over the strong objections of the ER staff. It came down to them saying things like “unless we can get your kidney’s working dude, you could soon be dead.” Thus I decided to stay in the ER the night. I wouldn’t have been able with all this pain to go to work the next day, and figured I might as well suffer in pain in the ER for a little longer. And unfortunately this ER isn’t good at pain management. After complaining a lot, they finally conceded to give me a less than whopping 60 mg of codeine every 8 hours. While OTC is Canada, even low doses of codeine are prescription only in the US.
Come late Wednesday, I was still in bad shape, and I was so scared at that point I agreed to stay yet another night in the hospital. By noon today, I was feeling much better, and the blood work showed major improvement. They still wanted to keep me around until tomorrow (?!), but since things had stabilized enough that even though they didn’t think it was the best of ideas, since I wanted to go that bad it was adequately safe. I just got home about an hour ago.
Best the hospital could figure is that while they couldn’t figure out what caused things to start going bad, I ended up making things much worse from all the ibuprofen combined with the calcium carbonate. The calcium carbonate ended up throwing my electrolytes off to cause alkalosis. (Too high blood pH.) The result being that combined with the ibuprofen, my kidneys shut down.
Is it this easy to get in such bad medical shape regarding the kidneys? I’d have thought it wouldn’t. I was totally horrified when the doctor said “acute kidney failure”. I do know enough about medicine to realize kidneys aren’t a optional organs. Looks like I may have dodged a big bullet here. Needless to say that as of immediately I am going to be VERY careful about what I put in my body.