SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

P29
THE ROLE OF COCAINE IN HEROIN RELATED DEATHS. HYPOTHESIS ON THE HEROIN­
COCAINE INTERACTION
A. Polettini*, V. Poloni, A. Groppi, C. Stramesi, C. Vignali, L. Politi, M. Montagna
Department of Legal Medicine & Public Health, University of PaVia, Via Forlanini 12, 27100 PAVIA,
Italy
In recent years, drugs-of-abuse related deaths involving cocaine observed at the Department of Legal
Medicine & Public Health of Pavia have shown an increase, probably reflecting the rising trend in cocaine
use in Western Europe: "pure" cocaine deaths have increased from 6 cases in 1979-1991 (1.5% of drug-ofabuse
deaths) to 13 in 1992-2002 (3,2%), and in the same periods heroin related deaths (HRDs) involving
cocaine amounted to 8 (1.9%) and 22 (5.4%), respectively. In the attempt to investigate the role of cocaine
in HRDs, acute narcotism cases testing positive for cocaine and/or metabolites in blood (>10 ngtml,
COC+) were examined. Only cases occurred from 1997 to 2001 were considered as in this period all data
were obtained using the same analytical procedures (free morphine and total morphine by DPC Coat-A­
Count radioimmunoassay before and after enzymatic hydrolysis, cocaine and metabolites in blood by SPE,
TMS derivatization and GC-MS). The median, minimum and maximum concentration of free morphine
(FM) and total morphine in blood (TM), urine (UM) and bile (BM) in the COC+ group (n=9) were
compared with those calculated in the group of "pure" HRDs (no other drugs detected in blood, COCo,
n=30). Differences among the two groups were statistically evaluated using the two-tailed Mann-Whitney
U Test. Statistical analysis was also carried out including in both groups cases testing positive (>2 mgtdL)
for blood alcohol (COC+, n=19; COCo, n=76). The median TM was found to be lower in the COC+ group
(0.32 mg/l vs. 0.90 mg/l, P=0.0214) and also the median FM (0.08 mgtl vs. 0.28 mg/l, P=O.l064). The
FMITM ratio was similar in the two groups (0.33 and 0.35) and also UM (21.0 mg/J and 18.0 mg/J),
whereas BM was higher (90.0 mgtl vs. 49.0 mgtl, P=0.0268). Similar results were obtained by repeating
statistical analyses after including in the two groups cases with positive blood alcohol concentration
(BAC). This picture is very different from what was previously observed for the heroin-ethanol interaction
in HRD cases CA. Polettini et al., J. Anal. Toxico!., 23, 570, 1999), and updated with more recent data: in
the high-ethanol (HE, BAC >100 mg/dl) group TM was lower than in the low-ethanol (LE, BAC:5100
mgtdl) group (0.59 mg/l vs. 0.90 mgtl, P=0.0180), the FMlTM ratio was higher (0.66 vs. 0.43, P=0.0038),
FM was equal, UM was lower (0.21 mgtl vs. 26.5 mg/J, P=O.OOOl), and so BM (10.0 mgtl vs. 26.5 mg/l,
P"-'0.0156). Indeed, the observed lower TM in the COC+ and in the HE groups support the hypothesis ofan
interaction of both cocaine and ethanol with heroin in the occurrence of death. Ethanol results suggest that
a pharmacokinetic interaction is prevalent (inhibition of heroin metabolism, as suggested by the increased
FM/TM ratio, resulting in reduced urinary and biliary excretion). In the case of cocaine, a
pharmacodynamic interaction seems to prevail, as the FMITM ratio remains unchanged and UM and BM
are not lower in the COC+ group. This hypothesis could not be confirmed owing to the paucity of data and
the many uncontrolled variables involved.
Keywords: heroin related death, cocaine, interaction
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