Flunitrazepam: psychomotor impairment, agitation and paradoxical reactions

Benzodiazepines are sedatives used for anxiolysis, hypnosis, muscle relaxation and the treatment of epilepsy. Paradoxical reactions including agitation, talkativeness, confusion, disinhibition, aggression, violent behavior and loss of impulse control may, however, occur in some subjects. It has been claimed that high doses of flunitrazepam may cause aggression on a more regular basis in all individuals. The present study makes use of a Norwegian forensic toxicological database containing analytical results from drivers suspected of driving under the influence and suspects of violent crime to analyze the relationship between behavior and blood flunitrazepam concentration. Four-hundred and fifteen cases of drivers suspected of driving under the influence and seven cases of suspects of violent crime were studied. These selected cases had flunitrazepam as the only drug in blood samples and had been evaluated by a clinical test for impairment (CTI) performed by a police physician at the time of blood sampling. The impaired drivers had higher blood flunitrazepam concentrations than the not impaired drivers. Multivariate analysis revealed that both blood flunitrazepam concentration and age of the suspected drivers had independent impact on impairment, indicating tolerance with age. Most of the effects measured were sedative effects of flunitrazepam and these effects were related to flunitrazepam level. Possible paradoxical reactions were observed in a subgroup of 23 individuals (6%), but these reactions did not relate to blood flunitrazepam concentration. The suspects of violent crime showed similar degree impairment and had not more paradoxical reactions than the suspected drugged drivers. The findings were in agreement with other research that claims paradoxical reactions should be viewed as a reaction in certain individuals, and does not support the notion that flunitrazepam in high concentration produces aggression in all individuals taking the drug.

The CYP2C19 genotype and the use of oral contraceptives influence the pharmacokinetics of carisoprodol in healthy human subjects

AIMS

The aim of the present study was to investigate if subjects with one normal and one non-functional CYP2C19 allele (intermediate metabolizers; IMs) metabolized carisoprodol differently than individuals with two normal CYP2C19 alleles (extensive metabolizers; EMs) We also wanted to investigate whether the use of oral contraceptives influences the metabolism of carisoprodol in EMs and IMs. Impairing effects on psychomotor coordination and feelings of sedation were studied by comparing IMs with EMs following their ingestion of a single dose of 700 mg carisoprodol.

METHODS

Thirty-seven healthy Caucasian volunteers participated in the study, of whom 25 were not using any drugs known to interact with CYP2C19, including two poor metabolizers (PMs) (CYP2C19 *2/*2 or CYP2C19 *2 /*4), 11 IMs (CYP2C19 *1/*2 or CYP2C19 *1/*4) and 12 EMs (CYP2C19 *1/*1); the remaining 12 participants were six EMs and six IMs using oral contraceptives. A single oral dose of 700 mg of carisoprodol was given, and blood drug concentrations were followed for 11 h and 45 min. During this time period, different pharmacodynamic measurements were made.

RESULTS

IMs had a longer elimination half life (T(1/2)) (127 min; 95% confidence interval (CI) 95, 159) than EMs (96 min; 95% CI 84, 107) and a larger area under the concentration-time curve from 0 to infinity (AUC(0-infinity)) for carisoprodol (16.3 microg h ml(-1) ; 95% CI 11.9, 20.7) than EMs (11.3 microg h ml(-1) ; 95% CI 7.8, 14.8). The use of oral contraceptives was accompanied by larger AUC(0-infinity) for carisoprodol in both EMs (18.5 microg h ml(-1); 95% CI 10.7, 26.3) and IMs (26.0 microg h ml(-1) ; 95% CI 18.8, 33.2). EMs using oral contraceptives also had a longer T(1/2) (117 min; 95% CI 92, 143) and higher maximum carisoprodol concentration than EMs not using oral contraceptives. No significant differences in pharmacodynamic parameters were found between subjects in the different genotype groups or between users and non-users of oral contraceptives.

CONCLUSIONS

Subsequent to a single-dose administration of carisoprodol, the carisoprodol AUC was approximately 45% larger in CYP2C19 IMs than in EMs. The use of oral contraceptives increased the AUC by approximately 60% in both EMs and IMs. Despite these pharmacokinetic effects, no significant differences with respect to the CYP2C19 IM and EM genotypes were observed in the acute impairing effects of a single dose of carisoprodol.

The concentrations, appearance and taste of nine sedating drugs dissolved in four different beverages

Sedating drugs are reported to be used in cases where people have been drugged unwittingly. In the present experiments we studied whether nine sedating medicinal drugs would dissolve in four different beverages to reach concentrations which could possibly cause impairment and whether the drugs altered the appearance and taste of the beverages. Nine sedating medicinal drugs were added separately to water, beer, Coca-Cola and ethanol. Drug concentrations were measured 5, 10, 20 and 40 min after spiking. The amount of drug in one swallow (50 mL) was calculated. Appearance and taste were recorded after 10 min. Flunipam, Sobril, Valium and Xanor dissolved faster than Rohypnol, Imovane, Somadril, Rivotril and Dolcontin. Ten minutes after adding Flunipam, Sobril, Imovane (in beer and Coca-Cola), Valium and Xanor, the concentrations had reached more than 50% of maximum theoretical concentration. Most of the drugs caused sediment, pieces and/or turbidity in one or more of the beverages. Some of the solutions were dyed from added Rohypnol (turquoise or green), Dolcontin (red) and Valium (yellow). Flunipam and Valium caused extensive frothing in beer. The tastes of Imovane and Somadril were distinct in all the beverages, while the taste of other drug solutions was less distinct. The ingestion of all solutions could probably have caused impairment. All the nine drugs were, however, apparent to the consumer from the altered appearance and/or taste of the beverages.

Carisoprodol intoxications and serotonergic features

The symptoms and signs of carisoprodol intoxications do not resemble those caused by its metabolite meprobamate. Meprobamate most probably produces its effects through the GABAergic neurotransmitter system. The signs and symptoms of carisoprodol intoxications, however, are not easily explained by interaction with this neurotransmitter system. In the present study, four cases of carisoprodol intoxications are presented with emphasis on the presence of serotonergic signs and symptoms. All four cases fulfilled three different sets of criteria for the diagnosis of serotonin syndrome. These findings could indicate that an increased serotonin level in the central nervous system could explain some of the symptoms and signs of carisoprodol intoxications. This may have implications for the clinical evaluation and treatment of such intoxications. Since few laboratories routinely screen for carisoprodol it is important to keep this drug in mind when encountering intoxications displaying serotonergic symptoms.

Plasma concentrations during naltrexone implant treatment of opiate-dependent patients

AIMS

To evaluate individual variations in plasma concentrations over time in patients with naltrexone implants.

METHODS

Ten opioid-dependent patients received up to four implants. Plasma samples were collected regularly for the analyses of naltrexone and the metabolite beta-naltrexol.

RESULTS

The median naltrexone C(max) was 12.3 (range 5.8-22.1) ng ml(-1), the median T(max) was 1 day (range 3 h to 35 days), and the median length of time that plasma concentrations were above 1 ng ml(-1) was 55 (range 30-80) days. Two patients reported heroin use without experiencing any effect. Tissue reactions were recorded in two patients after repeated implantation.

CONCLUSION

Marked individual and intraindividual variations in naltrexone concentrations were observed. Further studies should be performed to evaluate the need for therapeutic drug monitoring during naltrexone implant treatment.

[Arsenic poisoning]

BACKGROUND

Arsenic poisoning has been discussed frequently in Norway during the past year on the background of a suspected crime case. There seem to be several uncertainties regarding this issue, also in the medical profession.

MATERIAL AND METHODS

We have searched the literature and made a review based upon the present knowledge about arsenic and arsenic poisoning.

RESULTS

Arsenic can be found in numerous chemical compounds with different properties. Inorganic arsenic compounds, like arsenic trioxide, are reactive and can cause damage to the body. Organic arsenic compounds, which are found in high concentrations in fish and shellfish, are not considered toxic. Ingestion of inorganic arsenic affects cellular energy production; lethal poisonings can occur. Common clinical features after acute intoxication with arsenic are dysphagia, nausea, vomiting, abdominal pain, diarrhoea, intense thirst, and muscle cramps. Clinical features of chronic poisoning are hyperkeratosis in the palms and foot soles, pigmentation and conjunctivitis.

INTERPRETATION

Arsenic poisoning is a rare condition; its clinical features are uncharacteristic and the diagnosis must be confirmed by analysis of blood, urine and hair.

Impairment due to intake of carisoprodol

BACKGROUND

Carisoprodol is a centrally acting muscle relaxant commonly used for lower back pain. It is a drug of abuse and has been detected among impaired drivers. Carisoprodol's active metabolite meprobamate is thought to act through the GABA(A) receptor complex and produces a well-known impairing effect. It is unclear whether therapeutic intake of carisoprodol leads to impairment, and the effect of supratherapeutic doses has not been investigated. Possible impairment could further be a product of the parent drug and/or the metabolite meprobamate. The present study aimed to investigate if carisoprodol had an impairing effect by it self.

METHODS

From the database at the Norwegian Institute of Public Health, Division for Forensic Toxicology and Drug Abuse 62 cases containing carisoprodol and meprobamate as only drugs were identified. These cases constituted our material.

RESULTS

Impaired drivers (73%) had higher blood carisoprodol concentration than not impaired drivers (27%), but no difference in blood meprobamate concentration was found for all the drivers viewed together. Amongst occasional users of carisoprodol, however, there was difference in blood meprobamate concentration between not impaired and impaired drivers. The risk of being judged impaired rose with increasing blood carisoprodol concentration, but not with increasing blood meprobamate concentration. The clinical effects of carisoprodol as measured by the clinical test for impairment (CTI) resembled those of benzodiazepines with some important differences such as tachycardia, involuntary movements, hand tremor and horizontal gaze nystagmus, which may be specific carisoprodol effects.

CONCLUSION

Carisoprodol probably has an impairing effect by itself, at least at blood concentration levels above which can be seen after therapeutic intake of the drug.

[Of what significance are diseases, intoxication and suicide in fatal traffic accidents?]

BACKGROUND

A large proportion of fatal car accidents cannot be explained by traffic environment, technical defects or risk-taking behaviour. Driver impairment from disease, alcohol, drugs or suicidal impulses may be involved.

MATERIAL AND METHOD

Autopsy protocols from 167 car drivers involved in traffic accidents in Southeast Norway 1994-99 were reviewed retrospectively.

RESULTS

In 89 of 135 deaths caused by trauma, there were no apparent explanations for the accident prior to autopsy. No differences were found with regard to signs of disease between drivers involved in unexplained and explained accidents. Drivers dead from trauma compared to drivers dead from natural causes had less often ischemic heart disease (p < 0.01). Blood alcohol level was above the statutory limit in 20% of drivers in both unexplained and explained accidents, and drugs were found in the blood in 27% of such cases. Only 13% of drivers in explained accidents collided with large motor vehicles, compared to 44% of the unexplained accidents.

INTERPRETATION

Drivers with fatal injuries sustained in unexplained accidents seldom show signs of cardiac disease that could have contributed to the accident. It seems that such unexplained accidents are more often due to driving under the influence of alcohol or drugs, or to possible suicidal impulses.

Testing for benzodiazepine inebriation--relationship between benzodiazepine concentration and simple clinical tests for impairment in a sample of drugged drivers

OBJECTIVE

To study how the various 25 subtests and observations of the Norwegian clinical test for impairment related to the blood benzodiazepine concentrations of apprehended drivers suspected of driving under the influence of benzodiazepines. The impact of single-dose intake in non-daily users of benzodiazepines on the clinical picture of inebriation was also studied.

METHODS

Included in the study were 818 drivers suspected of driving under the influence of non-alcoholic drugs with blood samples containing only one benzodiazepine. We determined which of the 25 subtests and observations of the clinical test for impairment related significantly to the blood benzodiazepine concentrations.

RESULTS

Significantly related to blood benzodiazepine concentrations were 13 subtests and observations. Of these, 9 withstood adjustment for a variety of background variables. Single dose intake in non-daily users only influenced 3 subtests and observations after adjustment for blood benzodiazepine concentration and background variables. Romberg's test, 1 observation concerning alertness (oriented for time and place), 4 tests on motor and coordination (walk and turn on line, finger-to-nose and finger-to-finger tests), 2 observations on speech (articulation and content) and 1 observation regarding appearance (general conduct) were related to blood benzodiazepine concentrations.

CONCLUSION

Many of these simple clinical tests are included in the standardized field sobriety test and are of value in revealing benzodiazepine impairment. The present study offered some possible additions. Combinations of these robust tests can also be used to reveal benzodiazepine inebriation in other contexts.

Association between blood carisoprodol:meprobamate concentration ratios and CYP2C19 genotype in carisoprodol-drugged drivers: decreased metabolic capacity in heterozygous CYP2C19*1/CYP2C19*2 subjects?

Carisoprodol is metabolized to meprobamate by the cytochrome P450 enzyme CYP2C19, encoded by the polymorphic CYP2C19 gene. Most studies on carisoprodol metabolism have been carried out on individuals phenotyped for CYP2C19 activity using the probe drug S-mephenytoin. We aimed to investigate whether the ratio of carisoprodol to meprobamate in a 'real life' setting could be predicted by CYP2C19 genotype or, more specifically, if high carisoprodol : meprobamate ratios in drugged drivers could be ascribed to the presence of mutant CYP2C19 alleles. From original material comprising 358 blood samples from apprehended drivers, two polarized groups were selected; a high-ratio group of 11 subjects where the carisoprodol : meprobamate ratio was >1 and a low-ratio control group of 23 subjects where the ratio was <0.31. Genotyping was carried out for the CYP2C19*2, CYP2C19*3 and CYP2C19*4 alleles. DNA samples from 94 healthy blood donors were used as reference material. The number of mutant alleles in the high-ratio and low-ratio groups was significantly higher and lower, respectively, than in the reference material. The increased number of mutant alleles in the high-ratio group was not due to the presence of many poor metabolizers, but to a high number of heterozygous individuals with the genotype CYP2C19*1/*2. This result indicates a gene dosage effect where the carisoprodol : meprobamate ratio reflects the number of active CYP2C19 alleles. The metabolism of carisoprodol to meprobamate is dependent on CYP2C19 genotype. Heterozygous individuals with the CYP2C19*1/*2 genotype have a reduced capacity for metabolizing carisoprodol, and should probably be regarded as intermediate metabolizers of this drug.

[Impaired driving as an indicator of drug abuse: what consequences for treatment?]

Driving under the influence of drugs is a growing problem as the number of apprehended drivers in Norway has increased 2.5 times since 1990. At least two drugs are usually detected. The majority of offenders have been arrested earlier. This paper gives an overview of studies of impaired drivers.

MATERIAL AND METHODS

The re-arrest rate among 1102 drivers under the influence of drugs was followed for 7.5 years and compared with a group of 850 drivers under the influence of alcohol. Another study included 874 drivers with benzodiazepine detections followed retrospectively for 11 years. Earlier arrests and drugs detected first time were recorded. The third study recorded deaths among drugged (n = 918) and drunken (n = 2531) drivers for 7.5 years, compared with same age group in the general population.

RESULTS

57% of drugged and 28% of drunken drivers were re-arrested. More the 60% of drivers with benzodiazepine detections had been arrested earlier. Alcohol was most the commonly detected substance at first arrest. The standardised mortality ratio for male drugged drivers was 18.1 (14.9-21.8), for drunken drivers 3.7 (2.9-4.7).

INTERPRETATION

Our results show that drugged drivers represent risk groups with multi-drug use, frequent re-arrests and early death. Other efforts combined with fines, prison and withdrawal of driving licence should be considered. Some countries have follow-up programmes that include control of drug use by urine testing before a re-issue of the driving licence is considered.

[Naltrexone implants--a pilot project]

BACKGROUND

An increasing number of Norwegian heroin addicts have had naltrexone implants abroad without proper documentation. The authors established a joint project to study duration and safety.

MATERIAL AND METHODS

Methodology to measure naltrexone in plasma was developed. 10 patients had 21 implants. Plasma samples were collected before, one and three hours after implantation, daily for one week, then weekly. Patient satisfaction, side effects and unwanted medical events were recorded.

RESULTS

Patients had a protective level of naltrexone for 35-80 days. Side effects were few. Two patients had abstinence reactions caused by insufficient detoxification. Two patients had their repeat implants removed because of tissue reactions. One patient developed hepatitis C infection in the second week after implantation. One had transient increase in transaminases after heavy multi-drug use. The others were without signs of hepatic toxicity.

INTERPRETATION

Use of implants secures a prolonged period of naltrexone protection. Implants are mostly well tolerated, but tissue reactions to repeat implants could be a problem. Evaluation of the patients should be thorough and the treatment integrated in a competent follow up.

Codeine and clinical impairment in samples in which morphine is not detected

OBJECTIVE

Codeine metabolises partly to morphine by the liver enzyme CYP2D6, which is subject to genetic polymorphism. It has been suggested that analgesic effects of codeine are due to the morphine metabolite. Codeine effects other than analgesia have been less investigated in this regard, but it has been suggested that sedation, for example, might be independent of morphine formation. The aim of our study was to investigate the influence of codeine alone, without concomitant presence of morphine, on a clinical test for drunkenness (CTD) performed in relation to suspected drugged driving.

METHODS

Cases with detected codeine but not morphine, nor any other drug above the limit of detection, were selected from the database of suspected drugged drivers at National Institute for Forensic Toxicology, Oslo, Norway. Codeine blood concentration in these samples was compared with the conclusions from the corresponding individual CTD.

RESULTS

Of the 43 cases fulfilling the selection criteria, 23 were judged as "not impaired", and 20 as "impaired". Mean blood codeine concentration in the "not impaired" group was 143 ng/ml (95% CI 48-238, median 63 ng/ml). Mean concentration in the "impaired" group was 213 ng/ml (95% CI 146-279, median 159 ng/ml). There was a statistically significant concentration difference between the two groups. Codeine blood concentrations were further grouped as "moderate", "medium high" and "high". When adjusted for age, gender and chronic use, the odds ratios for being judged as impaired were 6 (95% CI 1-32, P=0.04) and 19 (95% CI 2-182, P=0.01) for the "medium high" group and the "high" group, respectively, relative to the "moderate" group.

CONCLUSION

Codeine appeared to have some dose-dependent effect on the central nervous system that may lead to impairment as judged from a CTD, independent of measurable blood morphine concentrations. This supports the view that some codeine effects do not seem to be mediated by morphine.

Pharmacokinetic differences of morphine and morphine-glucuronides are reflected in locomotor activity

The main metabolites of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), have been considered to participate in some of the effects of morphine. There is limited knowledge of the pharmacokinetics and dynamics of morphine and the main metabolites in mice, but mice are widely used to study both the analgesic effects and the psychomotor effects of morphine. The present study aimed to explore pharmacokinetic differences between morphine and morphine-glucuronides in mice after different routes of administration, and to investigate how possible differences were reflected in locomotor activity, a measure of psychostimulant properties. Mice were given morphine, M3G or M6G by different routes of administration. Serum concentrations versus time curves, pharmacokinetic parameters and locomotor activity were determined. Intraperitoneal administration of morphine reduced the bioavailability compared to intravenous and subcutaneous administration, but not so for morphine-glucuronides. The two morphine-glucuronides had similar pharmacokinetics, but morphine demonstrated higher volume of distribution and clearance than morphine-glucuronides. The present results demonstrated no locomotor effect of M3G, but a serum concentration effect relationship for morphine and M6G. When serum concentrations and effect changes were followed over time, there was some right hand shifts with respect to locomotor activity, especially during the declining phase of the concentration curve and particularly for M6G.

Clinical impairment of benzodiazepines--relation between benzodiazepine concentrations and impairment in apprehended drivers

BACKGROUND

Acute intake of benzodiazepines is followed by concentration-dependent deterioration of performance in controlled experimental studies. Whether this is true in a population of benzodiazepine users is uncertain. We studied the relationship in a population of suspected drugged drivers.

METHODS

In Norway physicians examine and take blood samples from nearly all suspected drivers. Our material comprised 818 samples containing only one benzodiazepine and our reference group consisted of 10,759 cases containing only alcohol.

RESULTS

159 drivers (19%) were considered as not impaired and 659 (81%) as impaired. None of the background factors, e.g. gender, age or time of day when apprehended, related significantly to either the physician's conclusion or to blood levels of benzodiazepines. Impaired subjects had significantly higher blood levels of diazepam (n=411) (P<0.001), oxazepam (n=73) (P<0.05) and flunitrazepam (n=211) (P<0.05) than those not impaired. The risk of being assessed as impaired did rise with increasing benzodiazepine blood level, with odds ratios (ORs) for being assessed as impaired of 1.61, 3.65 and 4.11 for the three supratherapeutic drug levels. The corresponding OR found for different elevated blood-alcohol concentrations were 1.49, 2.94 and 10.49.

CONCLUSION

The blood concentration of benzodiazepines was the only characteristic which was related to impairment. This indicated a drug-concentration related effect of benzodiazepines on performance and paves the way for a discussion on legal limits for benzodiazepines in relation to driving.

Increased mortality among previously apprehended drunken and drugged drivers

Most studies in the field of impaired driving have focused on the hazards imposed on society by the impaired drivers, whereas little attention has been paid to the future outcome of the drivers. The aim of the study was to identify mortality rates and causes of death among drunken and drugged drivers during the years after apprehension. Prospective cohort study on apprehended drunken and drugged drivers, follow-up period: 7.5 years, outcome variable: death. Apprehended drivers 20-39 years old who provided samples positive for alcohol (n=2531) or drugs other than alcohol (n=918) constituting the total national samples of these two driver categories in 1992. The mortality rate among male drunken drivers was higher than in an age-matched Norwegian population (standardised mortality ratio, SMR=3.7 (95% Cl 2.9-4.7). The SMR for drugged drivers was 18.1 (14.9-21.8) for men and 27.9 (14.4-48.8) for women. In a subgroup of male drugged drivers using heroin, SMR was 39.8 (28.8-53.6). The dominant causes of death among drunken and drugged drivers were drug poisoning/overdose, accidents and suicide. Apprehension for drunken or drugged driving and subsequent analytical verification, is an indicator of increased risk of future premature death in the age group 20-39 years, particularly for drugged drivers. To our knowledge this is a new finding, and studies to confirm it should be carried out in other countries. If verified, the results should lead to the consideration of new public health approaches towards apprehended impaired drivers.

Rearrest rates among Norwegian drugged drivers compared with drunken drivers

The rearrest rates among Norwegian drugged (n=1102) and a group of drunken drivers (n=850) (BAC: 0.16-0.19%) apprehended during 1992, were 57% (n=629) and 28% (n=238), respectively, when followed prospectively for 7 years. The most important risk factors for recidivism among drugged drivers were previous arrests for drugged or drunken driving (rearrest rate among previous arrests: 73%, no previous arrest: 42%), multi-drug detection at selection (multi-drug: 62%, single drug: 41%), sex (male: 61%, female: 35%) and age (below 36 years: 60%, 36 years and older: 44%). Most of the recidivist drugged drivers were rearrested during the year of selection (21%), followed by 13, 7 and 6%, retrospectively, during the following years. When followed both retrospectively and prospectively for a period extending from 1984 to 1998, 71% (n=779) and 40% (n=344) of the selected drugged and drunken drivers, respectively, were arrested two or more times.

Urinary excretion of diazepam metabolites in healthy volunteers and drug users

Urinary excretion profiles of diazepam metabolites were investigated. The subjects were healthy volunteers receiving one single 10-mg dose of diazepam or drug abusers starting a prison sentence. Urinary excretion of metabolites was analysed by immunological screening, liquid chromatography and gas chromatography-mass spectrometry. Relating the metabolite concentration to creatinine concentration in the specimens decreased sample-to-sample variations. In some cases such correction could protect a subject from erroneous accusations of a new intake.

[Centrally acting muscle relaxants and traffic hazards]

BACKGROUND

An increasing number of the centrally acting muscle relaxants were withdrawn from the Norwegian market during the 1988-98 period. The only drug in this group now marketed in Norway is carisoprodol. The National Institute of Forensic Toxicology in Norway analyses all blood samples from suspected drugged drivers. In later years there has been a marked increase in the number of blood samples testing positive for carisoprodol or meprobamate (the major metabolite).

MATERIAL AND METHODS

480 cases testing positive for central muscle relaxants in the years 1984-1998 were further studied.

RESULTS

Compared with blood samples positive primarily for benzodiazepines, there were more women in the group (39% vs. 15%), and fewer drugs and less alcohol were detected.

INTERPRETATION

The positive samples may indicate misuse or abuse due to the fact that high drug concentrations and concomitant use of benzodiazepines were frequent. This knowledge should have implications for doctors prescribing centrally acting muscle relaxants.

Lack of crosstolerance between morphine and morphine-6-glucuronide as revealed by locomotor activity

Morphine-6beta-glucuronide is a major metabolite of morphine. We wanted to examine whether the effects related to opiate CNS stimulation could be mediated by different receptors for morphine and M6G by studying the development of crosstolerance between these two drugs. The effect studied was locomotor activity in C57BL/6JBom mice. We observed a dose-dependent development of tolerance to daily injections of morphine, with 20 micromol/kg giving the most rapid development of tolerance, apparent already on the second day of treatment. This was also observed for the same dose of M6G. Crosstolerance to M6G was measured both after 1 day pretreatment and 7 days pretreatment with morphine 20 micromol/kg, while the crosstolerance to morphine was tested only after 1 day pretreatment with M6G (20 micromol/kg). Lack of crosstolerance towards M6G after 1 day of morphine pretreatment was observed, whereas crosstolerance to M6G was observed after 7 days of exposure to morphine pretreatment. Crosstolerance after M6G pretreatment to morphine was observed. It was concluded that the main part of the effect caused by M6G was mediated through a specific M6G receptor.

Toxicity of drug abuse--amphetamine designer drugs (ecstasy): mental effects and consequences of single dose use

MDMA (3,4-methylendioxymethamphetamine) is the most commonly used substance within the 'ecstasy' group of drugs. MDMA interferes with serotonin and catecholamine transporters in the central nervous system to increase monoamine synaptic levels and thereby mediate the majority of its central nervous effects. These range from wanted effects like euphoria, central nervous stimulation, and feeling of closeness to mild hallucinations, impairment of cognition and co-ordination and further to serious reactions like agitation, disturbed and bizarre behaviour, and possibly psychosis. The full picture of the consequences of these transitory changes is not known. It has been assumed that the risk of being involved in fatalities and accidents during the state of MDMA influence is increased, but this possible risk increase has so far not been determined. Observations of the prevalence of MDMA involvement in cases of reckless driving and the MDMA blood concentrations measured indicate a risk increase comparable to that observed after use of amphetamines.