The most common and most likely answer to this crossword clue is the 10 letter word BENZEDRINE
I've seen this crossword clue in The Times
B
E
N
Z
E
D
R
I
N
E
More clues leading to the result BENZEDRINE
Buddy explains!

The straight part
We know that "drug" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case drug = benzedrine.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does BENZEDRINE mean?
BENZEDRINE noun- The racemic mixture of amphetamine (dl-amphetamine).