Define "drugs". Lottsa oldsters smoke reefer. Tim Leary did acid on his deathbed. But, I don't think that speed for a week would be in order when you're in your 60's.
I read in High Times magazine years ago that the opium growing tribes in the Golden Triangle looked down seriously on people getting addicted to the opium but that old folks were welcome to take to the pipe. Sound like a great pension plan to me. Be fucking productive in your strongest years but then relax a little when you get, ummm, "tired".