"I don't like the looks of an 80 yr old granma smoking a doobie either, but neither do I want to see her using a suppository and taking a crap on a handicapped toilet."
I'd rather have an 80 yr old grandma who uses a suppository than an 80 yr old stoned grandma behine the wheel of a car.
Again, that's an issue for medical doctors, not government. If somebody takes medication that impairs driving ability, the doctor orders them to refrain from driving. Beer impairs driving ability, will you campaign to bring back prohibition too?