Abstract

ORTEGA PEREZ, A.. Was this individual poisoned by cocaine? (and II): estimations based on the effects of the drug and on the concentrations of benzoylecgonine. Cuad. med. forense [online]. 2003, n.33, pp.13-24. ISSN 1988-611X.

In this second review, the factors that determine the relationships between the dose of cocaine absorbed and the subject's response are presented. Being numerous, it is understandable that in observational studies of individuals arriving at the hospital's emergency department or in those who die from the effects of cocaine, no relationship has been found between the two parameters. Although it is possible to quantify the concentration of non-conjugated (free) cocaine in biological samples, the most common choice in forensic medicine is to measure benzoylecgonine. However, this metabolite is not psychoactive and its pharmaco-kinetic properties are different from those of cocaine and, as such, clinical evaluation of dose-effect relationship with benzoylecgonine is even weaker. The factors that influence benzoylecgonine concentrations in a biological sample from a corpse are also presented in this review. These factors need to be borne in mind in interpreting the results provided by the laboratory. Hence, estimating the possible effects of cocaine in a subject using the measured value of benzoylecgonine is even more difficult than performing this evaluation based on the cocaine concentrations measured. In conclusion, since concentrations of cocaine and its metabolites in biological samples vary widely and do not predict the severity of clinical findings, the incidence of adverse events, prognosis or the need for therapeutical intervention, these values need to be interpreted with caution. They should not be the main element in deter-mining the cause-of-death when cocaine is suspected of being the causative agent.

Keywords : Benzoylecgonine; cause of death; cocaine; dose-effect relationship; expert witness; route of administration; variations.

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