Except for one patient I saw.
She brought in her med list and on it was a list of allergies and her reaction to the med. So it would say something like, "metoprolol- light headed", or "lisinopril- cough". Then for one med it said, and I'm not making this up, "benadryl- zombie".
Usually the principle is, "Do no harm", but in this case it was, "Do no harm. But if you do do some harm, destroy the brain 'til it don't get back up no more."