Drug poisoning deaths in Sweden show a predominance of ethanol in mono-intoxications, adverse drug–alcohol interactions and poly-drug use

Abstract

Over a 10-year period (1998–2007) all deaths in Sweden classified by forensic pathologists as fatal drug poisonings ( N = 6894) were retrieved from a toxicology database (TOXBASE) belonging to the National Board of Forensic Medicine. The deaths were further classified as suicides N = 2288 (33%), undetermined N = 2260 (33%) and accidental N = 2346 (34%). The average age (±SD) of all victims was 49.1 ± 15.9 years and men 47.4 ± 15.6 years were 5-year younger than women 52.2 ± 15.8 years ( p < 0.01). Most of the deceased (78%) were poly-drug users although a single drug (mono-intoxications) was found in 22% of all poisoning deaths ( p < 0.001). The number of drugs in blood samples varied from 1 to 12 with a median of 3–4 per case. Mono-intoxication deaths were mostly ethanol-related ( N = 976) and the mean and median blood-alcohol concentration (BAC) was 3.06 g/L and 3.10 g/L, respectively. The BAC decreased as the number of additional drugs in blood increased from 2.15 g/L with one drug to 1.25 g/L with 6 or more drugs. The mean (median) concentrations of non-alcohol drugs in mono-intoxication deaths were morphine ( N = 93) 0.5 mg/L (0.2 mg/L), amphetamine ( N = 39) 2.0 mg/L (1.2 mg/L), dextropropoxyphene ( N = 33) 3.9 mg/L (2.9 mg/L), dihydro-propiomazine ( N = 32) 1.6 mg/L (1.0 mg/L) and 7-amino-flunitrazepam ( N = 28), 0.4 mg/L (0.3 mg/L). Elevated blood morphine in these poisoning deaths mostly reflected abuse of heroin as verified by finding 6-monoacetyl morphine (6-MAM) in the blood samples. When investigating drug poisoning deaths a comprehensive toxicological analysis is essential although the results do not reveal the extent of prior exposure to drugs or the development of pharmacological tolerance. The concentrations of drugs determined in post-mortem blood are one element in the case. The autopsy report, the police investigation, the findings at the scene and eye-witness statements should all be carefully considered when the cause and manner of death are determined.