Definition: Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
Input: Abstract: The users of illicit drugs is endangered by both unpredictable concentrations of the drugs and by unexpected adulterants that may be present. Cocaine has been adulterated or admixed with numerous substances, among them local anesthetics, amphetamine, phencyclidine, and strychnine. We report three cases of thallium poisoning following nasal insufflation of a substance that was believed to have been cocaine.

Thallium poisoning in cocaine abusers.