WordNet
n. a person who takes drugs [syn: substance abuser, user]
Wikipedia
The term drug user refers to the taking of a drug, either by swallowing, smoking, injecting or any other way of getting the drug into the blood stream.
Usage examples of "drug user".
A convicted drug user, no matter how desperate his circumstances may become, is denied these benefits for the rest of his life.
Rachel's young, which is in her favor, but she's a drug user, which is definitely not.
But both could be explained by the possibility that he was schizophrenic and a drug user.
Bannister brought in-well, we both saw that it appeared to have been written by a different person, or someone on drugs, but she was evidently not a drug user.
There were also sufficient puncture marks in her left arm and both ankles to indicate she had been an intravenous drug user, although no narcotic had registered in any blood test.