I like the long lasting (8 - 12 hours) form of ibuprofen called Alleve. Don't combine it with Diamox. Both of them can cause problems with indigestion. Taken both together once, they gave me a bad case of the runs...no fun. Tylenol is a good pain killer and is safe for children. Aspirin and Ibuprofen, and Alleve are best for their anti inflamatory effect (helpful for muscle pain). I am not sure any of the pain killers, aspirin, or the non steroidal anti inflamatories (aspirin, ibufrofen, alleve etc.) really do any thing for altitude sickness. But every one up on the big hike comes down with sore muscle pain. Some Drs. recommend anti inflamatory medicine to prevent the inflamation which comes from overdoing it...less soreness during and afterwards.