I personally prescribe loads of painkillers, including the whole range of the WHO ladder, and many of those patients have liver tests. It rarely happens that we have to discontinue Tylenol due to hepatitis. I see people on NSAIDs with kidney failure every week. So again yes, Tylenol is toxic. But from personal experience, it's rarely a clinically relevant problem.
Frankly, I'm not sure why NSAIDs are considered the safer option. There was a period of time when I was young, where I had tried various painkillers for treatment of headaches. Every time I had tried an NSAID, my chest felt like it was going to explode, and it became difficult to breathe. Later learned that they may increase the risk of heart attacks and strokes (of which I have a family history). For these reasons, I've sworn to never take them, and only take acetaminophen on rare occasions when pain is bad enough.
