Personal experience, plus what I saw during SAR missions, convinced me in some cases, you do need some serious pain meds as well as/or anti-inflamitories when in back country, or in a bugout/survival situation. Most commercial FAK's, IMHO, are very limited in pain and anti-inflammatory meds.
My personal support kit currently has 25 Advil 200mg in it along with a full script of hydrocodone since I destroyed my ACL and fractured my femur and tibia. I have a 10 count Advil tube, (about the size of a chapstick) that will hold 25 Advil 200mg tablets.

I have this sized easy to identify packaging of Bayer, Advil, Dramamine, Benedryl, Tylenol that have been replacked (filled) in my Personal Support Med Kit. Wrapping the label with clear packing tape keeps the name/directions from being worn off the labels. The are marked with expiration dates also.