Drift off with an endless assortment of sedatives (7)
I believe the answer is:
deviate
'drift' is the definition.
(I've seen this in another clue)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for deviate that I've seen before include "Turn aside from accepted way" , "Change from a course or standard" , "Turn aside from course of action" , "Differ" , "Depart from an established course" .)