A fatal case of poisoning with ethanol and psychotropic drugs with putrefactive changes

Summary

We present a fatal case involving poisoning with paroxetine, flunitrazepam, and ethanol, with putrefactive changes. Quantitative toxicological analysis showed that the concentrations of paroxetine and 7-aminoflunitrazepam, a metabolite of flunitrazepam, in the femoral blood were 0.28 µg/ml and 0.17 µg/ml, respectively. We also detected an ethanol level of 2.90 mg/ml and an n-propanol level of 0.10 mg/ml. We concluded that the cause of death was due to the interaction of paroxetine, flunitrazepam, and ethanol. The effects of putrefactive changes should be considered during forensic toxicological evaluation.

Keywords:
flunitrazepam – ethanol – paroxetine – gas chromatography mass spectrometry (GC/MS).

The evaluation of toxicity due to ingestion of multiple psychotropic drugs, with or without ethanol, is an important problem in the field of forensic toxicology (1,2). Paroxetine, a selective serotonin reuptake inhibitor, has a high affinity for serotonergic uptake sites. This drug increases the concentration of serotonin in the synaptic cleft by inhibiting its re-uptake (3,4). Flunitrazepam, an N-methyl-2´-fluoro analogue of nitrazepam (5,6), is a central nervous system depressant that may cause drowsiness, hangover, fatigue, dizziness and ataxia (5), and additive effects may occur when ethanol is co-ingested (6). Here we report a case of death with putrefactive changes involving the toxicity of paroxetine, flunitrazepam, and ethanol.

CASE REPORT 

A Japanese male in his fifties was found dead in his room in the middle of summer. He had a history of alcohol dependence. Subsequent investigation by the authorities revealed that he had been receiving therapy for depression and alcohol problems, and was taking prescribed drugs.

The deceased was 168 cm in height and 74.5 kg in weight. Putrefactive changes were evident. The heart weighed 389 g and contained 37 ml blood without coagulum. The brain weighed 1405 g and was discolored. The left and right lungs weighed 498 g and 484 g, respectively, and were congested. Approximately 20 ml of stomach contents, which included a red-brownish fluid, were noted. Other than congestion and putrefactive changes, no notable changes in other organs were observed. A drug screening test using a Triage^TM (Biosite Diagnostic Inc., San Diego, CA, USA) panel was positive for benzodiazepines. Postmortem samples of the left/right heart blood, femoral venous blood, urine, and stomach contents were collected for toxicological examination and stored at -20°C until analysis.

Toxicological analysis 

Toxicological analysis was performed using a 6890N gas chromatograph combined with a 5973 MS mass spectrometer (Agilent Technologies, Santa Clara, CA, USA). Identification and quantification of each drug were performed as described (7). Chromatographic separation was performed with a fused-silica capillary column DB-5MS (30 m × 0.25 mm I.D., 0.25 µm film thickness; J&W Scientific, Folsom, CA, USA). The operating conditions for gas chromatography mass spectrometry (GC/MS) were as follows. The carrier gas was helium in constant pressure mode. The injector temperature was set at 260 °C. The oven temperature was set at an initial temperature of 60 °C for 2 min, and was programmed to then rise 20 °C/min to 300 °C with maintenance at 300 °C for 10 min. The MS system was operated in the electron-impact mode with an electron energy of 70 eV and an ion source temperature of 230 °C. The sample solution (1 µl) was injected in splitless mode. We used diazepam-d₅ as an internal standard. The retention times were fixed using the retention-time locking technique with diazepam-d₅ as the locking compound (7). Samples were prepared as described (7). Extraction was performed with a cartridge Focus column (Varian, Lake Forest, CA, USA), and acetylation was performed. The eluate was evaporated and reconstituted in 100 µl ethyl acetate, and 1 µl of this solution was injected into the GC/MS.

Quantitation of ethanol and n-propanol was performed using head-space gas chromatography as described (8,9).

Toxicological analysis identified paroxetine, 7-aminoflunitrazepam, which is a metabolite of flunitrazepam, ethanol and n-propanol. Table 1 shows the quantitation of each substance in the blood, urine, and stomach contents of the deceased, and also summarizes the fatal and therapeutic levels of these substances (6,10–13).

DISCUSSION 

In the present case, although the blood concentration of paroxetine exceeded therapeutic levels by approximately 4-fold (10), this concentration was still lower than the fatal concentration for paroxetine alone (12). However, to the best of our knowledge, no reports have been published describing the effects of putrefaction on postmortem blood paroxetine levels.

We detected an ethanol level of 2.90 mg/ml and an n-propanol level of 0.10 mg/ml in the blood, and an ethanol level of 3.17 mg/ml and an n-propanol level of 0.02 mg/ml in the urine. Because n-propanol forms in the blood or urine during the process of putrefaction, we must consider postmortem formation of ethanol in the present case (14,15). However, endogenous production of ethanol may be as high as 0.15% (1.5 mg/ml) in the blood (14). The antemortem ethanol concentration can be roughly estimated by deducting 25 times the concentration of n-propanol from the concentration of ethanol in the blood or urine (15). Although we could not precisely determine the antemortem blood ethanol levels, we were able to estimate the presence of ethanol in the blood at the time of death.

We detected 7-aminoflunitrazepam, but not flunitrazepam in any sample. This may have been due to postmortem bioconversion of flunitrazepam to 7-aminoflunitrazepam (16). In addition, the presence of 7-aminoflunitrazepam is an important marker of flunitrazepam usage (6,17). Because a portion of flunitrazepam is converted to 7-aminoflunitrazepam (16), its effect can generally be estimated from the sum total of the flunitrazepam and 7-aminoflunitrazepam concentrations in the femoral blood (17).

Flunitrazepam is a central nervous system depressant (5), and the concentration that is fatal is lower when ethanol is co-ingested (6). The concentration of 7-aminoflunitrazepam plus ethanol in our case was at fatal levels (6), and additive depressive effects on central nervous system function would have occurred due to the high levels of paroxetine. We concluded that the cause of his death in this case was due to the ingestion of multiple psychotropic drugs plus ethanol.

CONCLUSION 

We sometimes observe postmortem changes in daily forensic practice, and have only a limited amount of data concerning the postmortem changes or the effects of drug interactions with ethanol. The present case indicates that we should pay more attention to the effects of postmortem putrefactive changes and the toxicity of drug interactions when evaluating the cause of death. 

CONFLICT OF INTEREST

The authors declare that there is no conflict of interests regarding the publication if this paper.

Correspondence address:

Dr. Hiroshi Kinoshita

Department of Forensic Medicine

Faculty of Medicine, Kagawa University

1750-1, Miki, Kita, Kagawa 761-0793, Japan

tel.: +81-87-891-2140; fax: +81-87-891-2141

e-mail: kinochin@med.kagawa-u.ac.jp