An index of fatal toxicity for drugs of misuse

Objective : To determine the lethal toxicity of five commonly-used illicit substances by relating the number of associated deaths to their availability. Methods : An index of toxicity was calculated for each of five drugs [heroin, cocaine/crack, ecstasy (MDMA), amphetamine and cannabis] as the ratio of the number of deaths associated with that substance to its availability in the period 2003–2007. Three separate proxy measures of availability were used (number of users as determined by household surveys, number of seizures by law enforcement agencies and estimates of the market size). All data are related to England and Wales only. Results : There was a broad correlation between all three denominators of availability. Not unexpectedly, heroin and cannabis showed, respectively, the highest and lowest toxicities. The index of fatal toxicity of MDMA was close to that of amphetamine and cocaine/crack. There was a rank correlation between this index and other measures of lethal toxicity based on safety ratios. Conclusions : These results are contrary to widely-held public views of the relative fatal toxicity of MDMA.