© 2004 Canadian Medical Association or its licensors Research

Populations of illicit drug users are characterized byhigh rates of illness and death,1,2 and drug overdoseis a major cause of death. Studies from Australia, Europe and the United States indicate that, overall, an-nual rates of death due to overdose among illicit drug users are relatively stable, at about 1 % to 2%.2–5 In addi-tion, nonfatal overdose incidents are common and repre-sent an important cause of morbidity among illicit drug users.6 For example, among 581 people addicted to nar-cotics who were admitted to the California Civil Addict Program between 1962 and 1964, there were 284 deaths by the time of the third follow-up, 33 years later; of these, 61 (21.5%) were directly due to drug overdose or poison-ing.2 Other studies have provided further evidence of high rates of nonfatal overdose among illicit drug users; for ex-ample, up to two-thirds of heroin users have reportedly experienced a nonfatal overdose.6–8 In yet other studies, up to 89 % of injection drug users surveyed reported having witnessed an overdose.9–11 Epidemiologic estimates suggest that there may be as many as 100 000 injection drug users in Canada, most of whom use of illicit opioids in some form.12,13 Recent esti-mates have suggested 500 to 1000 overdose deaths per year in Canada during the past decade.14 During the 1990s, an overdose crisis developed in British Columbia, fuelled mostly by Vancouver incidents; annual overdose deaths in-creased substantially, from 67 in 1989 to 361 in 1993 and then to 416 in 1998, peaking at an average of more than 1 overdose death per day.14,15 Other data on Canadian drug user populations suggest substantial rates of overdose. O