For last 8 years, fatal nicotine intoxication cases have occurred constantly in Korea. Even though nicotine has been utilized for long time as a cigarette form, high concentration of liquid nicotine for e-cigarette became easily accessible after its global marketing in 2015. As a discrepancy of blood nicotine concentration between reported fatal cases and our postmortem cases was observed, we reviewed fatal nicotine poisoning cases in Seoul capital area from 2014 to 2021.

All decedents in Seoul capital area from 2014 to 2021 whose cause of death was fatal nicotine poisoning were retrospectively studied; the route of administration included injection or ingestion of e-liquid, and attachment of nicotine transdermal patches. The autopsies were carried out at Seoul Institute of National Forensic Service (NFS), and heart bloods and/or femoral vein bloods were submitted for toxicological analysis. As a substitute of blood sample, liver tissues were collected and analyzed. The concentrations of nicotine from biological samples were quantitated with liquid chromatography-tandem mass spectrometry (LC-MS/MS) after sample preparation. The concentrations of nicotine were evaluated with several parameters; method of administration, co-administered drug or alcohol etc.

Seventy-one fatal cases of nicotine were identified and analyzed. The average blood concentration of nicotine was 42mg/L in heart blood (range: 0.69–250, n=37) and 18mg/L in femoral vein blood (range: 0.33–130, n=64). The average nicotine concentration in liver tissue was 150mg/kg (range: 1.6–610, n=6). In a fatal case of poisoning with 70 nicotine transdermal patches, heart and femoral vein blood concentration of nicotine were 7.7mg/L and 3.3mg/L, respectively. The average femoral vein blood concentration was 19mg/L in fatal nicotine cases with no other drug or alcohol co-administered (range: 1.27–87, n=24), whereas that was 17mg/L in fatal nicotine cases with drug(s) and/or alcohol co-administered (range: 0.33–130, n=40). As a sub-group, the average femoral vein blood concentration was 11mg/L in the cases with alcohol but no other drug co-administered (range: 0.33–58mg/L, n=16).

In analysis of nicotine poisoning cases, the results should be interpreted with caution. Even though average value was presented here, the lethal blood concentration range was wide; from less than 1mg/L to more than 100mg/L. The tolerance at a certain concentration might be different whether the exposed person was a habitual smoker or a non-smoker. Also, co-administration of alcohol or drugs may increase the risk of death at lower nicotine concentration.