I read long ago that caffeine helps boost the effect of some OTC painkillers. It was mainly directed at aspirin, and that was when some aspirins and ibuprofens began to have caffeine added. I have read that Tylenol works the best for PMR patients and I certainly learned the hard way that ibuprofen does nothing for t his sort of pain. So in the AM the first thing I do when my coffeepot timer goes off and lets me know the coffee is ready, is to have a mug of strong black coffee with one Extra Strength Tylenol. Within 20 minutes my aches and pains are very eased and I can get up and start my day, thankfully, very well. At this stage, one Tylenol works fine, so I figured why mess with 2 if one works well enough.