I'm not a biochemist but... I thought some specific NSAIDS were "neurokinin-1 antagonists" or blocked pain pre-emptively at brain-level rather than after-the-fact at body-level? [insert vague hand-waving here] I read some studies a couple or three years ago when I needed to max out the efficiency of my anti-pain meds (cos bleeding insides, and can't take ♥ codeine ♥ for more than very short periods, &c). ::handwavium + pinch of salt::