Olaf H. Drummer

The incidence of drugs in drivers killed in Australian road traffic crashes.

The incidence of alcohol and drugs in fatally injured drivers were determined in three Australian states; Victoria (VIC), New South Wales (NSW) and Western Australia (WA) for the period of 1990-1999. A total of 3398 driver fatalities were investigated which included 2609 car drivers, 650 motorcyclists and 139 truck drivers. Alcohol at or over 0.05 g/100ml (%) was present in 29.1% of all drivers. The highest prevalence was in car drivers (30.3%) and the lowest in truckers (8.6%). WA had the highest rate of alcohol presence of the three states (35.8%). Almost 10% of the cases involved both alcohol and drugs. Drugs (other than alcohol) were present in 26.7% of cases and psychotropic drugs in 23.5%. These drugs comprised cannabis (13.5%), opioids (4.9%), stimulants (4.1%), benzodiazepines (4.1%) and other psychotropic drugs (2.7%). 8.5% of all drivers tested positive for Delta(9)-tetrahydrocannabinol (THC) and the balance of cannabis positive drivers were positive to only the 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (carboxy-THC) metabolite. The range of THC blood concentrations in drivers was 0.1-228 ng/ml, with a median of 9 ng/ml. Opioids consisted mainly of morphine (n=84), codeine (n=89) and methadone (n=33), while stimulants consisted mainly of methamphetamine (n=51), MDMA (n=6), cocaine (n=5), and the ephedrines (n=61). The prevalence of drugs increased over the decade, particularly cannabis and opioids, while alcohol decreased. Cannabis had a larger prevalence in motorcyclists (22.2%), whereas stimulants had a much larger presence in truckers (23%).

Methadone toxicity causing death in ten subjects starting on a methadone maintenance program.

Methadone maintenance therapy is designed to reduce the need for addicts to use heroin or other illegal opiates. Death in patients starting on such a program has not previously been documented. We report the death of 10 persons who died within days of starting a methadone maintenance program administered by general practitioners. Their bodies were subject to a full autopsy by forensic pathologists, with a full toxicological examination. The mean starting dose had been 53 mg, which had been increased to a mean of 57 mg by the final dose. Death occurred after a mean of 3 days. The mean blood methadone concentration at death was 2.1 mumol/L. Complete toxicological analysis showed that six subjects had additional drugs present including two with alcohol, two with benzodiazepines and morphine, and one with benzodiazepines alone. Pathological examination revealed the presence of chronic persistent hepatitis in all subjects and bronchopneumonia in five. The causes of death were given as methadone toxicity or methadone toxicity in combination with bronchopneumonia. Our observations highlight the dangers of methadone in the first days of starting on a maintenance program, particularly when the starting doses are relatively high and subjects have no demonstrated tolerance to opiates. Language: en

Fluorouracil therapy in patients with carcinoma of the large bowel: a pharmacokinetic comparison of various rates and routes of administration.

SummaryThe pharmacokinetics of fluorouracil after oral, intravenous and rectal administration were compared in 12 patients with colorectal cancers.Oral administration of 10 to 15mg/kg gave variable plasma levels (0 to 10.5μg/ml) and bioavailability (0 to 74%; mean 28%). Bioavailability increased markedly with increases in dose, suggesting saturation of the ‘frst pass’ hepatic metabolism of the drug. Differences in bioavailability could not be related to standard liver function tests or the presence of metastatic deposits i the liver.Plasma levels were not detectable after rectal administration in the 4 patients studied and were very low (0 to 8μg/ml) during high dose (20 to 30mg/kg/24h) slow intravenous infusion in 6 patients.These findings indicate that different dose schedules and routes of administration produce markedly different plasma levels. They suggest that the rate of degradation of fluorouracil by the liver is quite variable and may become saturated with increasing dose. For these reasons monitoring of plasma levels of the drug in individual patients may be useful.

Chromatographic screening techniques in systematic toxicological analysis

A review of techniques used to screen biological specimens for the presence of drugs was conducted with particular reference to systematic toxicological analysis. Extraction systems of both the liquid-liquid and solid-phase type show little apparent difference in their relative ability to extract a range of drugs according to their physio-chemical properties, although mixed-phase SPE extraction is a preferred technique for GC-based applications, and liquid-liquid were preferred for HPLC-based applications. No one chromatographic system has been shown to be capable of detecting a full range of common drugs of abuse, and common ethical drugs, hence two or more assays are required for laboratories wishing to cover a reasonably comprehensive range of drugs of toxicological significance. While immunoassays are invariably used to screen for drugs of abuse, chromatographic systems relying on derivatization and capable of extracting both acidic and basic drugs would be capable of screening a limited range of targeted drugs. Drugs most difficult to detect in systematic toxicological analysis include LSD, psilocin, THC and its metabolites, fentanyl and its designer derivatives, some potent opiates, potent benzodiazepines and some potent neuroleptics, many of the newer anti-convulsants, alkaloids colchicine, amantins, aflatoxins, antineoplastics, coumarin-based anti-coagulants, and a number of cardiovascular drugs. The widespread use of LC-MS and LC-MS-MS for specific drug detection and the emergence of capillary electrophoresis linked to MS and MS-MS provide an exciting possibility for the future to increase the range of drugs detected in any one chromatographic screening system.

Methods for the measurement of benzodiazepines in biological samples

A review of methods for the measurement of benzodiazepines in biological specimens published over the last five years is presented. A range of immunoassay procedures using EIA, ELISA, FPIA, agglutination or kinetic interaction of microparticles, or RIA methods are now available. Cross reactivities to benzodiazepines are variable such that no one kit will recognise all benzodiazepines and their relevant metabolites at concentrations likely to be encountered during therapeutic use. Prior hydrolysis of urine to convert glucuronide metabolites to immunoreactive substances improves detection limits for many benzodiazepines. Several radioreceptor assays have now been published and show good sensitivity and specificity to benzodiazepines and offer the advantage (over immunoassay) of being able to detect these drugs with equal sensitivity. Solvent extraction techniques using a variety of solvents were still popular and offer acceptable recoveries and lack of significant interference from other substances. A number of papers describing solid phase extraction procedures were also published. Direct injection of specimens into a HPLC column with back flushing were also successfully described. Seventy two chromatographic methods using HPLC, LC-MS, GC and GC-MS methods were reviewed. HPLC was able to achieve detection limits for many benzodiazepines using UV or DAD detection down to 1-2 ng/ml using 1-2 ml of urine or serum (blood). ECD detectors gave detection limits better than 1 ng/ml from 1 ml of specimen, which was an order of magnitude lower than for NPD. EI-MS offered similar sensitivity, whilst NCI-MS was capable of detection down to 0.1 ng/ml. Methods suitable for the separation of enantiomers of benzodiazepines have been described using HPLC. Electrokinetic micellar chromatography has also been shown to be capable of the analysis of benzodiazepines in urine.

Postmortem Drug Metabolism by Bacteria

Studies were undertaken to determine the possible role of enteric bacteria in the postmortem bioconversion of the nitrobenzodiazepines flunitrazepam, clonazepam, and nitrazepam. Flunitrazepam, clonazepam, and nitrazepam were completely metabolized in blood in the presence of eight species of enteric bacteria to their respective 7-amino-metabolites. The rates of metabolism, at 37 degrees C, ranged from 0.1 ng/mL/min for Streptococcus faecalis to 8.8 ng/mL/min for Clostridium perfringens. The rate of conversion was reduced to 87% by a combination of 0.7% (w/v) sodium fluoride and potassium oxalate, and almost completely inhibited (96%) by 1% (w/v) sodium fluoride. pH had variable effects on the rate of metabolic bioconversion of nitrobenzodiazepines, while increasing temperatures were found to generally increase the rate of nitrobenzodiazepine bioconversion. These data support the proposal that bacteria may mediate postmortem bioconversion of the nitrobenzodiazepines.

Postmortem drug analysis: analytical and toxicological aspects.

Publications focusing on the analysis of postmortem specimens for the presence of drugs were reviewed with particular reference to systematic toxicological analysis. Specimens included blood, liver, other solid specimens, and fly larvae. Extraction techniques published during the past 10 years most commonly used traditional solvent extraction techniques. High-performance liquid chromatography coupled to multichannel wavelength detection was most commonly used, which would easily lend itself to liquid chromatography-mass spectrometry. There were few practical differences in the assays validated for a range of postmortem specimens to those in other forms of forensic toxicology, unless substantially decomposed tissue was used. When putrefied specimens were analyzed, a back-extraction or other form of specimen cleanup was recommended to reduce interfering substances. Many immunoassays designed for urine have been adapted for use in blood and tissue homogenates. Immunoassays designed for blood analysis, however, are likely to have more useful cutoff values than immunoassays optimized for urine testing. Postmortem specimens provide less stability for a number of drugs than other types of specimens. This is particularly a problem for cocaine, heroin, and some antidepressants, antipsychotics, and benzodiazepines. A number of artifacts occur postmortem, which affects the concentration of drug in specimens. This includes postmortem redistribution for drugs with a high tissue concentration relative to blood. Consequently, the likely extent of any change in concentration is relevant to the interpretation of doses and drug effects.

Fatal methadone toxicity: signs and circumstances, and the role of benzodiazepines.

Objective: To describe the signs and symptoms and circumstances of fatal methadone toxicity and investigate the role of benzodiazepines in these deaths.

Postmortem Redistribution of Morphine and Its Metabolites

The postmortem redistribution of morphine, morphine-3-glucuronide, morphine-6-glucuronide and total morphine was assessed in 40 heroin-related deaths. In blood taken from subclavian, heart, and femoral regions, concentrations of morphine and its metabolites were similar. While there was a trend for higher concentrations in heart blood, when compared with femoral or subclavian blood, this was not significant. There was also no significant difference in concentrations between admission and autopsy blood in which the postmortem interval was on average 59 h. From our observations, significant postmortem redistribution of morphine and its metabolites seems unlikely.

Stability of Nitrobenzodiazepines in Postmortem Blood

Studies were undertaken to determine the stability of nitrobenzodiazepines and their 7-amino metabolites in water and blood. At 22 degrees C nitrazepam and clonazepam were stable in sterile fresh blood containing preservative over 28 days, whereas 25% of flunitrazepam was degraded. At 37 degrees C all three drugs were substantially lost over 9 h (29-51%). There was only a small loss observed for the 7-amino metabolites and no substantial amounts of parent drug and 7-amino metabolite were degraded in water under these conditions. In the absence of preservative substantial amounts (25-50%) of parent drugs were lost in fresh blood over 10 days at 22 degrees C. In bacterially-contaminated postmortem blood all three drugs were completely degraded over 8 h at 22 degrees C with almost all drug completely converted to the respective 7-amino metabolite. These metabolites were also partially degraded (10-20%) over 45 h at 22 degrees C. All 3 nitrobenzodiazepines were stable in blood stored for up to 24 months at -20 degrees C, or 4 degrees C over 10 months. Their respective 7-amino metabolites were, however, relatively unstable at -20 degrees C with a significant loss (29%) after 2 months. At 4 degrees C a 21% loss occurred after 1 month. Freeze/thawing was found not to affect the concentration of nitrobenzodiazepine and 7-amino metabolites. These results show that the nitrobenzodiazepines and their metabolites are unstable chemically and metabolically in blood. We advise that blood collected for the purpose of nitrobenzodiazepine determinations should be preserved with sodium fluoride, stored at -20 degrees C and assayed as soon as practicable, preferably within a week of collection.