Concentrations of zolpidem and zopiclone in venous blood samples from impaired drivers compared with femoral blood from forensic autopsies

The concentrations of zolpidem and zopiclone were determined in peripheral blood samples in two forensic materials collected over a 10-year period (2001-2010). The z-hypnotics were determined in venous blood from living subjects (impaired drivers) and in femoral blood from deceased persons (forensic autopsies), with the latter classified as intoxication or other causes of death. The z-hypnotics were determined in blood by capillary column gas chromatography (GC) with a nitrogen-phosphorous (N-P) detector after solvent extraction with n-butyl acetate. The analytical limit of quantitation (LOQ) was 0.02mg/L for zopiclone and 0.05mg/L for zolpidem and these have remained unchanged throughout the study. When death was attributed to drug intoxication (N=918), the median concentration of zopiclone in blood was 0.20mg/L compared with 0.06mg/L for other causes of death (N=1215) and 0.07mg/L in traffic offenders (N=691) (p<0.001). Likewise, a higher median concentration (0.30mg/L) was found in intoxication deaths involving zolpidem (N=357) compared with 0.13mg/L for other causes of death (N=397) or 0.19mg/L in impaired drivers (N=837) (p<0.001). Median concentration in blood of both z-hypnotics were appreciably higher in intoxication deaths when no other substances were identified; 0 70mg/L (N=12) for zopiclone and 1.35mg/L (N=12) for zolpidem. The median concentrations of z-hypnotics in blood decreased as the number of co-ingested substances increased for intoxication deaths but not other causes of death. The most prevalent co-ingested substances were ethanol in autopsy cases and diazepam in the motorists. This large compilation of forensic cases should prove useful when toxicologists are required to interpret concentrations of z-hypnotics in blood samples in relation to cause of death.     

Contributory and Incidental Blood Concentrations in Deaths Involving Citalopram

All cases presenting to the New South Wales Department of Forensic Medicine between January 1, 2001 and December 31, 2010 in which citalopram was detected were retrieved. A total of 348 cases were identified. Citalopram contributed to death in 21.0%, and was incidental in 79.0%. Cases in which citalopram was contributory to death had significantly higher blood citalopram concentrations than incidental cases (0.50 mg/L vs. 0.30 mg/L). Citalopram concentrations varied significantly by contributory status: sole citalopram toxicity (median = 1.30 mg/L), citalopram/other drug toxicity (0.50 mg/L), and incidental cases (0.30 mg/L). Citalopram concentrations also varied by suicide status, with the highest concentration found in suicides where citalopram contributed to death (0.70 mg/L) compared with 0.50 mg/L for nonsuicide cases where citalopram contributed to death. In almost all contributory cases (69/73), other psychoactive substances were also detected, most commonly benzodiazepines (47.9%), alcohol (45.2%), and opioids (40.1%).     

Zolpidem and driving impairment

Zolpidem, a non-benzodiazepine hypnotic, was identified in the blood of 29 subjects arrested for impaired driving. Zolpidem concentrations ranged from 0.05 to 1.4 mg/L (mean 0.29 mg/L, median 0.19 mg/L). In the subjects whose cases we reviewed where zolpidem was present with other drugs and/or alcohol, symptoms reported were generally those of CNS depression. Symptoms included slow movements and reactions, slow and slurred speech, poor coordination, lack of balance, flaccid muscle tone, and horizontal and vertical gaze nystagmus. In five separate cases, where zolpidem was the only drug detected (0.08-1.40 mg/L, mean 0.65 mg/L, median 0.47 mg/L), signs of impairment included slow and slurred speech, slow reflexes, disorientation, lack of balance and coordination, and "blacking out." Although no quantitative relationship between blood concentrations and degree of driving impairment is currently possible, it is reasonable to conclude that because of its specific activity as a sleep inducer, blood concentrations consistent with therapeutic doses of zolpidem have the potential to affect driving in a negative way, and that concentrations above the normal therapeutic range would further impair a person's level of consciousness and driving ability.     

Toxicology and characteristics of fatal oxycodone toxicity cases in New South Wales, Australia 1999-2008

All cases of fatal oxycodone toxicity presenting to the New South Wales Department of Forensic Medicine over the period January 1, 1999, to December 31, 2008, were retrieved. A total of 70 cases were identified. The mean age was 48.9 years, 58.6% were men, 21.4% were suicides, and in 30% oxycodone had not been prescribed to the decedent. Injecting drug users constituted 27.1% of cases, and oxycodone tablets were injected immediately prior to death by 21.4%. The mean blood oxycodone concentration was 0.40 mg/L (range 0.06-53.00 mg/L). In all cases, psychoactive substances other than oxycodone were also detected, most frequently hypnosedatives (68.6%), other opioids (54.3%), antidepressants (41.4%), and alcohol (32.9%). Preexisting systemic disease was common: cardiovascular (64.2%), pulmonary (49.3%), hepatic (66.7%), and renal (43.9%).     

Postmortem forensic toxicology of selective serotonin reuptake inhibitors: a review of pharmacology and report of 168 cases

This paper reviews the complex pharmacology of the new class of antidepressant medications exhibiting selective inhibition of serotonin reuptake. The four selective serotonin reuptake inhibitors (SSRIs) considered--fluoxetine, fluvoxamine, sertraline and paroxetine--can result in toxicity and death through contributing to serotonergic excess resulting in serotonin syndrome, inhibiting the metabolism of other centrally acting drugs, leading to accumulation of toxic concentrations, and exerting complex vasoactive effects on the vascular smooth muscle. This latter feature is of particular concern in patients with preexisting heart disease. An analytical method involving isolation of the drugs by liquid/liquid extraction at alkaline pH into n-butyl chloride, and analysis by gas chromatography/mass spectrometry (GC/MS) is described, together with some of its limitations. Toxicologic and cause and manner of death data were examined in 60 deaths involving fluoxetine, 5 involving fluvoxamine, 75 involving sertraline, and 28 involving paroxetine. Deaths involving drug toxicity were generally a result of ingestion of multiple drugs, and in only a small number of the cases was death attributed principally to the SSRI involved. The potential for drug interactions between members of this class of drugs is discussed as well as their metabolites and a variety of other therapeutic and abused drugs which can contribute to their toxicity. In the absence of other risk factors, the lowest concentrations determined to have resulted in death were 0.63 mg/L for fluoxetine, 0.4 mg/L for paroxetine, and 1.5 mg/L for sertraline. We had insufficient data to make even this crude assessment for fluvoxamine. Drug-induced elevation of serotonin concentrations may be a significant risk factor for patients with atherosclerotic cardiovascular disease (ASCVD). Other factors including preexisting disease and the presence of other drugs and their pharmacology need to be carefully considered before determining the appropriate cause and manner of death in these cases.     

Zolpidem distribution in postmortem cases

Zolpidem is the prototype of a class of sedative hypnotic drugs that are derivatives of imidazopyridine and is sold in the United States under the trade name Ambien. Over a four-year period, zolpidem was identified in eight cases investigated by the Office of the Chief Medical Examiner, State of Maryland. Zolpidem was identified by gas chromatography-nitrogen-phosphorus detection (GC-NPD) following an alkaline extraction and was confirmed by full-scan electron impact gas chromatography/mass spectrometry. Zolpidem was quantitated by GC-NPD in all specimens received. Five of the cases presented were deaths due to drug intoxication. In three of these cases, zolpidem was an incidental finding because the drug fatalities resulted from other drugs. In the other two cases of drug intoxication, zolpidem was present in elevated concentrations and was a contributing, but not exclusive cause of the drug intoxication. The remaining three cases were deaths that were not caused by drugs. The blood zolpidem concentrations in these cases were therapeutic (0.28, 0.12 and 0.19 mg/L, respectively). In six of the eight cases where both blood and urine were analyzed, the blood concentration was higher than the urine concentration. The distribution of zolpidem into the liver and kidney failed to identify any sequestration of the drug into either specimen.     

The relationship of methanol and formate concentrations in fatalities where methanol is detected

An automated headspace gas chromatography method was developed for the determination of formate (formic acid) in postmortem specimens, based on the in situ sulfuric acid-methanol methylation of formic acid to methyl formate. Diisopropyl ether was used as an internal standard. The method was applied to over 150 postmortem cases where methanol was detected. Of the 153 cases presented, 107 deaths were attributed to acute methanol toxicity. In the vast majority of the remaining 46 deaths, the methanol was determined to be present as a postmortem or perimortem artifact, or was otherwise incidental to the cause of death. Of the 76 victims who were found dead and blood was collected by the medical examiner, all but one had a postmortem blood formate concentration greater than 0.50 g/L (mean 0.85 g/L; n = 74). The sole exception involved suicidal ingestion of methanol where the blood methanol concentration was 7.9 g/L (790 mg/100 mL) and blood formate 0.12 g/L. In 97% (72/74) of the cases where blood was available, the blood formate was between 0.60 and 1.40 g/L. In 31 of the 153 cases, the victim was hospitalized and blood obtained on admission or soon after was analyzed for methanol and formate during the subsequent death investigation; the vast majority (27/30) had antemortem blood formate concentrations greater than 0.50 g/L. Cases with samples taken prior to death with blood formate concentrations less than 0.5 g/L can readily be explained by active treatment such as dialysis. The blood formate method has also been useful in confirming probable perimortem or postmortem contamination of one of more fluids or tissues with methanol (e.g., windshield washer fluid or embalming fluid), where methanol ingestion was unlikely.     

Post-mortem cases involving amphetamine-based drugs in The Netherlands. Comparison with driving under the influence cases

In this study we reviewed the post-mortem cases in the years 1999-2004 that were presented at the Netherlands Forensic Institute. The concentrations of amphetamine-based drugs in femoral blood from cases of suspected unnatural death were compared with concentrations in whole blood from non-fatal cases of driving under the influence (DUI cases) and with literature. Furthermore, the combinations with other drugs and/or alcohol were investigated. Amphetamine-based drugs were present in 70 post-mortem cases and 467 DUI cases. The most detected amphetamine-based drug was MDMA, followed by amphetamine. The presence of MDA could usually be explained by metabolism of MDMA. Methamphetamine and MDEA were rarely present. Frequently, the amphetamine-based drugs were taken in combination with alcohol and/or other non-amphetamine-based drugs such as cocaine or cannabinoids. The 70 post-mortem cases were divided into 38 amphetamine-based drug caused (i.e. the amphetamine-based drug directly caused or contributed to the death) and 32 amphetamine-based drug related deaths (i.e. death was not directly caused by the amphetamine-based drug). In the latter category, other (poly)drug intoxications and death by violence or drowning were the most frequent causes of death. In 30 cases, MDMA caused death directly. The range in blood concentrations of MDMA in these cases was substantial, i.e. 0.41-84 mg/L with a median concentration of 3.7 mg/L (n=30). MDMA blood concentrations in the MDMA related deaths (n=20) and in the DUI cases (n=360) varied up to 3.7 and 4.0 mg/L, respectively. Seven victims died from the direct effects of amphetamine; the blood concentration of amphetamine ranged from 0.24 to 11.3 mg/L, with a median concentration of 1.7 mg/L (n=7). The median concentrations of amphetamine in the amphetamine related deaths (n=13) and the DUI cases (n=208) were much lower, i.e. 0.28 and 0.22 mg/L, respectively. Amphetamine blood concentrations up to 6.0 and 2.3 mg/L were seen in the drug related deaths and DUI cases, respectively. The most frequently encountered amphetamine-based drugs in the investigated deaths were MDMA and amphetamine. The majority of MDMA- and amphetamine-caused deaths, i.e. 90% of these deaths, occurred with blood concentrations above 1.5 and 0.80 mg/L, respectively. MDMA and amphetamine blood concentrations in drug related deaths and DUI cases, however, overlap the range of fatal concentrations. Therefore, MDMA or amphetamine concentrations should never be used alone to establish the cause of death.     

Postmortem oxycodone and hydrocodone blood concentrations

There is limited data on postmortem oxycodone concentrations, consisting of three published reports with a total of 11 cases, many of which were polypharmacy cases. This report presents the results of a review of autopsy and coroner's reports from 10 counties for the years 2000 and 2001 to locate cases with oxycodone or hydrocodone exposure as a leading cause of death. Eighty-eight cases were located. Twenty-four deaths were attributed to oxycodone alone. Mean and median postmortem oxycodone blood concentrations were 1.23 mg/L and 0.43 mg/L, respectively. The range was 0.12 to 8.0 mg/L, with 13 cases (54%) < or = 0.5 mg/L. Seventeen deaths were attributed to hydrocodone alone. Mean and median postmortem hydrocodone blood concentrations were 0.53 mg/L and 0.40 mg/L, respectively. The range was 0.12 to 1.6 mg/L, with 11 cases (65%) < or = 0.5 mg/L. There were seven cases where the cause of death was attributed to the effects of a combination of hydrocodone and oxycodone. Mean oxycodone and hydrocodone blood concentrations were 0.34 mg/L and 0.14 mg/L, respectively. Forty cases involved polysubstance overdoses with significant involvement of other drugs and ethanol. Mean oxycodone and hydrocodone blood concentrations were 0.18 mg/L and 0.29 mg/L, respectively. The list of other substances involved was extensive but included ethanol, amitriptyline, methadone, codeine, propoxyphene, and acetaminophen. The findings of this study report oxycodone values associated with a fatality at blood concentrations lower than previously reported. This may represent enhanced information because of the larger sample group. Hydrocodone values associated with a fatality were similar to previously published values.     

One hundred seventy two deaths involving the use of oxycodone in Palm Beach County

Oxycodone is a potent semi-synthetic narcotic prescribed for the management of pain. Previous investigators have reported that the abuse of oxycodone is most frequently seen in conjunction with the abuse of other drugs, although fatalities have been reported with oxycodone alone. We undertook a retrospective review of cases investigated by the Palm Beach County Medical Examiner's Office in which postmortem toxicologic studies indicated the presence of oxycodone. A total of 172 consecutive cases were studied, including 18 in which death was attributed to oxycodone toxicity, 117 to combined drug toxicity, 23 to trauma, 9 to natural causes and 5 to another drug or drugs. The postmortem blood concentrations of oxycodone overlapped among the groups. The mean blood oxycodone concentration among the cases of oxycodone toxicity was 0.69 mg/L, combined drug toxicity 0.72 mg/L and trauma 0.62 mg/L. Concentrations were lower in cases of deaths attributed to natural causes and to another drug or drugs (mean each 0.087 mg/L). Benzodiazepines, detected in 96 cases, were the most common co-intoxicants in the cases of combined drug toxicity, followed by cocaine, which was found in 41. The most frequently encountered benzodiazepine was alprazolam. This study confirms that deaths in which oxycodone is a factor are most commonly cases of combined drug toxicity. The high incidence of alprazolam as a co-intoxicant has not been previously recognized.     

The PMMA epidemic in Norway: comparison of fatal and non-fatal intoxications

During a 6 month period (July 2010-January 2011) we observed 12 fatal intoxications and 22 non-fatal cases related to the drug paramethoxymethamphetamine (PMMA) in Norway (4.8 mill inhabitants). This toxic designer drug, also known as "Death", is occasionally found in street drugs offered as "ecstasy" or "amphetamine". The present study aimed to evaluate the cause of death, and to compare the PMMA blood concentrations in fatal and non-fatal cases. Methods for identification and quantification of PMMA are presented. The median age of fatalities was 30 years (range 15-50) with 67% males; in non-fatal cases 27 years (20-47) with 86% males. In the 12 fatalities, the median PMMA blood concentration was 1.92 mg/L (range 0.17-3.30), which is in the reported lethal range of 0.6-3.1 mg/L in peripheral blood and 1.2-15.8 mg/L in heart blood. In the 22 non-fatal cases, the median PMMA concentration was 0.07 mg/L (range 0.01-0.65). Poly-drug use was frequent both in fatal and non-fatal cases. The PMA concentrations ranging from 0.00 to 0.26 mg/L in both groups likely represented a PMMA metabolite. Three fatalities were attributed to PMMA only, six to PMMA and other psychostimulant drugs, and three to PMMA and CNS depressant drugs, with median PMMA concentrations of 3.05 mg/L (range 1.58-3.30), 2.56 (1.52-3.23) and 0.52 mg/L (0.17-1.24), respectively. Eight victims were found dead, while death was witnessed in four cases, with symptoms of acute respiratory distress, hyperthermia, cardiac arrest, convulsions, sudden collapse and/or multiple organ failure. In summary, all fatalities attributed to PMMA had high PMMA blood concentrations compared to non-fatal cases. Our sample size was too small to evaluate a possible impact of poly-drug use. A public warning is warranted against use and overdose with illegal "ecstasy" or "speed" drugs.     

Post-mortem cases involving amphetamine-based drugs in the Netherlands: Comparison with driving under the influence cases

In this study we reviewed the post-mortem cases in the years 1999–2004 that were presented at the Netherlands Forensic Institute. The concentrations of amphetamine-based drugs in femoral blood from cases of suspected unnatural death were compared with concentrations in whole blood from non-fatal cases of driving under the influence (DUI cases) and with literature. Furthermore, the combinations with other drugs and/or alcohol were investigated. Amphetamine-based drugs were present in 70 post-mortem cases and 467 DUI cases. The most detected amphetamine-based drug was MDMA, followed by amphetamine. The presence of MDA could usually be explained by metabolism of MDMA. Methamphetamine and MDEA were rarely present. Frequently, the amphetamine-based drugs were taken in combination with alcohol and/or other non-amphetamine-based drugs such as cocaine or cannabinoids. The 70 post-mortem cases were divided into 38 amphetamine-based drug caused (i.e. the amphetamine-based drug directly caused or contributed to the death) and 32 amphetamine-based drug related deaths (i.e. death was not directly caused by the amphetamine-based drug). In the latter category, other (poly)drug intoxications and death by violence or drowning were the most frequent causes of death.In 30 cases, MDMA caused death directly. The range in blood concentrations of MDMA in these cases was substantial, i.e. 0.41–84 mg/L with a median concentration of 3.7 mg/L (n = 30). MDMA blood concentrations in the MDMA related deaths (n = 20) and in the DUI cases (n = 360) varied up to 3.7 and 4.0 mg/L, respectively. Seven victims died from the direct effects of amphetamine; the blood concentration of amphetamine ranged from 0.24 to 11.3 mg/L, with a median concentration of 1.7 mg/L (n = 7). The median concentrations of amphetamine in the amphetamine related deaths (n = 13) and the DUI cases (n = 208) were much lower, i.e. 0.28 and 0.22 mg/L, respectively. Amphetamine blood concentrations up to 6.0 and 2.3 mg/L were seen in the drug related deaths and DUI cases, respectively. The most frequently encountered amphetamine-based drugs in the investigated deaths were MDMA and amphetamine. The majority of MDMA- and amphetamine-caused deaths, i.e. 90% of these deaths, occurred with blood concentrations above 1.5 and 0.80 mg/L, respectively. MDMA and amphetamine blood concentrations in drug related deaths and DUI cases, however, overlap the range of fatal concentrations. Therefore, MDMA or amphetamine concentrations should never be used alone to establish the cause of death.     

A validated method for the analysis of cannabinoids in post-mortem blood using liquid-liquid extraction and two-dimensional gas chromatography-mass spectrometry

Phenazepam is a long-acting benzodiazepine that, unlike other benzodiazepines, is currently not scheduled as a narcotic in Finland, most other European countries or the USA. It is used as an anxiolytic, sedative-hypnotic and anti-epileptic, mainly in Russia. In Finland, as well as in some other countries, an increase in the unauthorized use of phenazepam has been observed in recent years. In the one year period between July 1, 2010 and June 30, 2011 the prevalence of phenazepam in Finland was assessed among drivers apprehended for driving under the influence of drugs (DUID), in medico-legal autopsy cases and in police confiscations of illicit drugs. In DUID cases an LC-MS/MS method preceded by solid phase extraction was used for the determination of phenazepam. In the post-mortem investigations the sample preparation consisted of liquid-liquid extraction followed by derivatization and the determination was carried out by GC-MS. The police confiscations were analysed by GC-MS. There were 141 positive phenazepam cases among apprehended drivers, representing approximately 3.5% of all confirmed drug cases (n=4007) in this time period. The median (range) phenazepam blood concentration in DUID cases was 0.061 mg/L (0.004-3.600 mg/L). The median phenazepam concentration in cases with no concomitant stimulant use was significantly higher than the overall median concentration. Phenazepam was found in 17 medico-legal autopsy cases and the median (range) blood concentration was 0.048 mg/L (0.007-1.600 mg/L). Phenazepam was not considered by the medico-legal team to be the sole cause of death in any of the cases, the majority of them being accidental opiod overdoses. There were 26 seizures of phenazepam by the Police in the time period studied, some of the batches consisted of a mixture of phenazepam and stimulant designer drugs. The data show that phenazepam abuse is a widespread phenomenon in Finland. A typical user was a male multi-drug user in his 30s. The concentration range of phenazepam among apprehended drivers and medico-legal autopsy cases was wide and the drug was usually found along with other psychoactive drugs. Therefore, although it seems likely that phenazepam contributed to impairment of driving in some DUID cases, the extent of its effect remains unclear and further studies are needed to define the concentrations causing impairment and toxicity.     

Toxicologic analysis in cases of possible sudden infant death syndrome: a worthwhile exercise?

The diagnosis of sudden infant death syndrome (SIDS) is one of exclusion. At the Department of Forensic Medicine, Westmead Hospital, toxicologic analysis is performed as part of the postmortem examination of all apparent SIDS deaths. The results for the 5-year period January 1, 1994, to December 31, 1999, were audited to determine whether such routine testing was worthwhile. During this time there were 117 cases with a history consistent with SIDS. Drugs were detected in 19 (16%) of these cases. In 1 case, death was attributed to the finding of methadone. The presence of methadone was regarded as a possible contributing factor to death in a further 2 cases. The presence of possible methadone toxicity had not been expected from the history given before the examination in these 3 cases. In 114 cases there was a suitable sample for alcohol testing; in no case was alcohol detected. In 13 cases the postmortem examination revealed an anatomic cause of death (including 3 cases consistent with whiplash/shaken baby/impact head injury), which excluded a diagnosis of SIDS. In conclusion, routine toxicologic testing in all possible cases of SIDS death supplements the postmortem examination in excluding cases of non-SIDS.     

Fatal cardiac arrhythmia after repeated exposure to 1,1-difluoroethane (DFE)

A 42-year-old man was found dead after repeated exposure to 1,1-difluoroethane (DFE, Freon 152a), a propellant found in CRC Duster, a product intended for the removal of dust and lint. Toxicologic analysis detected DFE in femoral blood 136.3 mg/L, brain 117.5 mg/kg, liver 87.6 mg/kg, lung 60.3 mg/kg, adipose 235.7 mg/kg, and vitreous fluid 25.1 mg/L. The cause of death was determined to be a fatal cardiac arrhythmia due to intoxication with 1,1-difluoroethane. After comparison to previously published cases involving DFE, we suggest that analysis of adipose tissue for DFE and similar compounds, along with blood and other tissues, may be useful in distinguishing between acute versus chronic exposure. Adipose may also be a valuable alternate specimen for detection in cases where loss or elimination from blood is likely to have occurred.