Comparative toxicology of fatal heroin overdose cases and morphine positive homicide victims.

AIMS: To compare the blood toxicology of heroin overdose cases and morphine positive homicide victims.

DESIGN

Analysis of coronial cases.

SETTING

Sydney, Australia. Cases A total of 705 cases of death due to opioid toxicity and 28 morphine positive homicide cases (1 January 1998-31 December 2002).

FINDINGS: There was no significant difference between the median morphine concentrations of the overdose and homicide groups (0.50 versus 0.45 mg/l). The overdose group was more likely to have blood alcohol (OR 3.21) present, but less likely to have methadone (OR 0.26) and cannabis (OR 0.04). There was a significant negative correlation between blood morphine and alcohol concentrations among the overdose group (rho = -0.32), but not among the homicide group (rho = -0.03). Independent predictors of a higher blood morphine concentration were a lower alcohol concentration and a higher methadone concentration.

CONCLUSIONS

Morphine concentrations per se are not diagnostic of overdose. The study confirms the salience of concomitant alcohol consumption in such events.