SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

P37
QUANTITA TIVE APPROACH TO DRUG ALCOHOL INTERACTION BASED ON
POSTMORTEM DATA
A Koski*, I Ojanpera, E Vuor, Department of Forensic Medicine, University of Helsinki, FINLAND
Our objective was to investigate the drug-alcohol interaction in terms of postmortem concentrations of both
drugs and alcohol in fatal poisonings. As our target analytes, we chose the three drugs most commonly
causing fatal single-drug poisonings in Finland: the tricyclic antidepressant amitriptyline, the opioid
analgesic propoxyphene and the phenothiazine antipsychotic promazine. The effect of benzodiazepines
(BDZs) on drug and alcohol concentrations was also evaluated in the study.
The laboratory database was searched for fatal poisonings caused by A) amitriptyline, propoxyphene or
promazine alone, B) one of these drugs with alcohol present, or C) alcohol (ethanol) with one of these
drugs detected. In order to increase sample size, cases with therapeutic or subtherapeutic concentrations of
some of the most frequently occurring BDZs were also included, but separate statistical treatments were
performed to evaluate their effect. The drug and alcohol concentrations included in the study had been
measured in femoral venous blood. The final data set consisted of 116 amitriptyline cases, of which 60
(S2%) BDZ positive, 120 propoxyphene cases, of which 43 (36%) BDZ positive, and 96 promazine cases,
of which 42 (44%) were BDZ positive.
The blood drug concentrations found in the unmixed amitriptyline poisonings were compared with those
detected in the amitriptyline-alcohol cases, and likewise for propoxyphene and promazine. The blood
alcohol concentrations found in the drug-alcohol poisonings were in turn compared with those in a
previously compiled reference group consisting of fatal alcohol poisonings caused by alcohol alone
(n=61S).
The median drug concentrations in unmixed drug poisonings (BDZ+) and drug-alcohol poisonings (BDZ+)
were 3.S (2.1) mg!l and 1.9 (0.7S) mg!1 for amitriptyline, 8.2 (4.9) mg/l and 6.1 (2.7) mg/I for
propoxyphene, and 6.3 (7.6) mg/l and 6.7 (S.I) mg/l for promazine. Regarding the effect of BDZs, the
difference between the median drug concentrations was statistically significant in amitriptyline poisonings
with and without BDZs (p