[Research Progress on Forensic Toxicology of Z-drugs]

The Z-drugs (zolpidem, zopiclone, and zaleplon), as the innovative hypnotics, have an improvement over the traditional benzodiazepines in the management of insomnia. Z-drugs have significant hypnotic effects by reducing sleep latency and improving sleep quality, though duration of sleep may not be significantly increased. As benzodiazepines, Z-drugs exert their effects through increasing the transmission of γ-aminobutyric acid. Z-drugs overdose are less likely to be fatal, more likely would result in poisoning. Z-drugs can be detected in blood, urine, saliva, and other postmortem specimens through liquid chromatography-mass spectrometry techniques. Zolpidem and zaleplon exhibit significant postmortem redistribution. Z-drugs have improved pharmacokinetic profiles, but incidence of neuropsychiatric sequelae, poisoning, and death may prove to be similar to the other hypnotics. This review focuses on the pharmacology and toxicology of Z-drugs with respect to their adverse effect profile and toxicity and toxicology data in the field of forensic medicine.

Myocardial Injury without Electrocardiographic Changes after a Suicide Attempt by an Overdose of Glimepiride and Zolpidem: A Case Report and Literature Review

A 40-year-old diabetic man was admitted to our hospital for poor glycemic control. During hospitalization, he took 42 mg glimepiride and 50 mg zolpidem as a suicide attempt. The following day, the creatine kinase-MB fraction and troponin I levels were elevated to 112 IU/L and 8.77 ng/mL, respectively, without any electrocardiographic abnormalities. The patient recovered completely without any complications. Four weeks later, coronary computed tomography angiography and myocardial perfusion scintigraphy revealed moderate one-vessel coronary disease without the evidence of myocardial ischemia or old infarction. Cardiac-specific markers must be considered in sulfonylurea-induced hypoglycemic patients, particularly when the patient is unconscious and does not exhibit any clinical manifestations.

A fatal case of thiacloprid poisoning

Neonicotinoid insecticides are considered to be less toxic to humans compared to older insecticides such as organophosphates, carbamates, pyrethroids, and organochlorine compounds. However,reports of severe human toxicity with neonicotinoids are emerging. Acute human thiacloprid poisoning and death as a result have not been reported in the literature so far. Here we report a case of thiacloprid poisoning resulting from deliberate ingestion in a 23-year-old man, manifesting with status epilepticus, respiratory paralysis,rhabdomyolysis, metabolic acidosis, and acute kidney injury (AKI), and ultimately giving rise to refractory shock and death. Thiacloprid can cause fatal human toxicity when ingested heavily, and absence of an effective antidote raises concern in this regard.

Coma with absent brainstem reflexes resulting from zolpidem overdose

Zolpidem is a nonbenzodiazepine hypnotic with a favorable adverse effect profile. There are single reports of respiratory decompensation associated with zolpidem overdose. We report a case ofa young woman with depression who developed deep coma with respiratory failure and a loss of brainstem reflexes as a result of zolpidem overdose. Supportive management led to a complete recovery of neurologic function. Acute zolpidem overdose should be considered in the differential diagnosis of coma with absent brainstem reflexes.

Medication Sleuth: An Important Role for Pharmacists in Determining the Etiology of Delirium

Delirium is characterized by disturbances of consciousness, attention, cognition, and perception and is the most common reason for acute cognitive dysfunction in hospitalized elderly patients. Causes of delirium can be multifactorial, and a careful medical and medication history can help determine the underlying cause of behavioral disturbances. A 65-year-old patient with a history of chronic pain, insomnia, and multiple medical problems, who presented with altered mental status and aggressive behavior, is described. The patient had taken an overdose of zolpidem prior to admission, and she required chemical and physical restraints and one-on-one care for safety. With time and washout of the zolpidem, the patient's behavior did not improve. On the second day of admission, medication reconciliation of this patient's medication profile helped to reveal a medication cause for this patient's delirium. A pharmacist should be included early in the process of obtaining a medication history. Recommendations for the management of chronic pain and insomnia in the elderly are presented.

[Acute poisoning with neonicotinoid insecticide acetamiprid]

Acetamiprid belongs to a new class of insecticides called neonicotinoids, which have different effects from other insecticides. Neonicotinoids act as selective agonists at the nicotinic acetylcholine receptors, therefore their toxicity is higher to insect pests than to humans. Cases of acetamiprid poisoning are still rare, because neonicotinoids have been released in the market only within the last decade. We experienced a case of acute acetamiprid poisoning and measured the blood concentration of acetamiprid. A 79-year-old man had ingested acetamiprid and got medical attention two hours after ingestion. On arrival, he had consciousness disturbance (GCS-8), hypotension, nausea, vomiting and hyperglycemia, but had no constricted pupils nor mucous supersecretion which are characteristic in organophosphate poisoning. Gastric lavage was performed and activated charcoal and laxative were administered. Paroxysmal atrial fibrillation persisted until 11 hours after ingestion. The next day, his symptoms with regards to the effects of acetamiprid improved and he was discharged from the hospital without complication. Blood concentration of acetamiprid on arrival, approximately 2 hours after the ingestion, was 21.1 microg/ml.

A case of green urine after ingestion of herbicides

The development of discolored urine may have many possible causes. Here we present the case of a 76-year-old woman who was admitted after ingesting the inorganic herbicides, mefenacet and imazosulfuron. Her urine color changed to green almost immediately. Since the patient had no specific medication or medical history we considered that the most likely cause of the change in urine color was the ingestion of the herbicides. Spectrophotometric analysis of the urine was conducted and a peak was observed in the green area of the wavelength spectrum. These findings show that mefenacet and imazosulfuron should be considered in the differential diagnosis of green discolored urine.

Comparison of zolpidem and zaleplon exposures in Texas, 1998-2004

Zolpidem and zaleplon are used for the treatment of insomnia. The objective of this study was to compare the patterns of zolpidem and zaleplon exposures reported to Texas poison control centers during 1998-2004. There were 5842 total reported zolpidem exposures, of which 2918 (50%) were isolated exposures, and 467 total reported zaleplon exposures, of which 201 (43%) were isolated exposures. Zolpidem patients were 62% male and 67% adult. Zaleplon patients were 67% male and 34% adult. The exposure was intentional in 62% of zolpidem and 58% of zaleplon exposures. The exposure occurred at the patient's own residence in 94% of zolpidem and 97% of zaleplon exposures. Management occurred outside of a health care facility for 29% of zolpidem and 32% of zaleplon exposures. The medical outcome involved no symptoms due to exposure for 29% of zolpidem and 44% of zaleplon exposures, a statistically significant difference. Although many of the most frequently reported adverse clinical effects for the two drugs were similar (drowsiness, slurred speech, hallucinations, ataxia, tachycardia, dizziness, confusion, vomiting), the proportion of exposures with a given adverse clinical effect was generally lower for zaleplon. Thus, although zolpidem and zaleplon exposures were generally similar with respect to patient gender and age, exposure reason and site, and management site, zaleplon exposures were less likely to result in minor medical outcomes or manifest as adverse clinical effects.

The use of therapeutic plasmapheresis in the treatment of poisoned and snake bite victims: An academic emergency department's experiences

The objective of this study is to describe the clinical status, procedural interventions, and outcomes of critically ill patients with poisoning and snake bite injuries presenting to a tertiary-care emergency department for treatment with therapeutic plasmapheresis. Records of 20 patients who presented to our academic emergency department over a 2-year period and who underwent plasmapheresis for poisoning or snake bite were retrospectively reviewed. Plasmapheresis was performed using centrifugation technology via an intravenous antecubital venous or subclavian vein catheter access. Human albumin or fresh frozen plasma were used as replacement fluids. Data extracted from the patient record included demographic data, clinical status, and outcome measures. Sixteen patients underwent plasmapheresis because of toxicity from snake bite. Three patients were treated for drug poisoning (phenytoin, theophylline, bipyridene HCl) and one patient for mushroom poisoning. Haematologic parameters such as platelet count, PT, and INR resolved rapidly in victims of snake bite injuries after treatment with plasmapheresis. Loss of limbs did not occur in these cases. Seven patients required admission to the intensive care unit. One patient with mushroom poisoning died. Mean length of hospital stay was 14.3 days (range 3-28 days) for all cases. Plasmapheresis was a clinically effective and safe approach in the treatment of snake bite envenomation and other drug poisoning victims especially in the management of hematologic problems and in limb preservation/salvage strategies. In addition to established conventional therapies, emergency physicians should consider plasmapheresis among the therapeutic options in treatment strategies for selected toxicologic emergencies.

Effects of herbicide and insecticide interaction on soil entomofauna under maize crop

The aim of this study was to evaluate the impact of the herbicide mixture nicosulfuron + atrazine, with or without the insecticide chlorpyrifos, onto soil entomofauna under maize crop. The treatments, applied 25 days after maize emergence, were represented by a weeded control without insecticide and herbicide, a weeded control with chlorpyrifos, and mixtures of nicosulfuron + atrazine, with or without chlorpyrifos. Arthropods populations, on the soil surface, as well as inside the soil under maize, were principally represented by mites (Arachnida: Acari), decomposer collembolans (Hexapoda:Parainsecta:Collembola) and predator ants (Hymenoptera:Formicidae). The nicosulfuron + atrazine mixture with chlorpyrifos and the isolated chlorpyrifos reduced the population dynamics of all insect groups on the soil surface compared to the weeded control. In the soil, mite and ant populations were reduced after application of the herbicide mixture with chlorpyrifos and of the isolated chlorpyrifos.

Alternative venlafaxine kinetics in overdose

The pharmacokinetics of venlafaxine in therapeutic doses is well established. It is metabolized by the cytochrome P450 enzymes including CYP2D6. The toxicokinetics in overdose is less well known.

CASE REPORT

A 33-year-old Caucasian female who ingested 3.0 g venlafaxine, and 210 mg zolpidem. The patient remained symptomatic for the following 24 h. Plasma pharmacokinetic analysis demonstrated a prolonged elimination half-life of venlafaxine, estimated to be 15.3 h. We postulate that the patient was a slow metabolizer of substrates for CYP2D6, an enzyme known to exhibit polymorphism.

Clinical syndrome associated with zolpidem ingestion in dogs: 33 cases (January 1998-July 2000)

Zolpidem is a nonbenzodiazepine hypnotic of the imidazopyridine class that is used to treat insomnia in humans. Zolpidem binds selectively to the benzodiazepine omega-1 receptor and increases the frequency of chloride channel opening, which results in inhibition of neuronal excitation. A retrospective study was conducted of zolpidem ingestion in dogs that were reported to the ASPCA Animal Poison Control Center (APCC) between January 1998 and July 2000. Data analysis included amount ingested, clinical effects, and time of onset of signs. Thirty-three reports of zolpidem ingestion in dogs (ranging in age from 5 months to 16 years) were evaluated. Approximate ingested dosages ranged from 0.24 to 21 mg/kg. Clinical signs reported included ataxia (18 dogs; 54.5%), hyperactivity (10 dogs; 30.3%), vomiting (7 dogs; 21.2%), and lethargy (5 dogs; 15.2%), as well as panting, disorientation, nonspecific behavior disorder, and hypersalivation (4 dogs each sign; 12.1%). Other signs reported include tachycardia, tremors, apprehension, vocalization, hypersalivation, weakness, and hyperesthesia. In 85% percent of reports, clinical signs developed within 1 hour and usually resolved within 12 hours. Although central nervous system (CNS) depression is reported as a primary effect of zolpidem in humans and would also be expected in dogs, information obtained from this study indicates that some dogs may exhibit a paradoxical excitation reaction. This effect appears to vary among individual dogs.

Radiopacity of clomipramine conglomerations and unsuccessful endoscopy: report of 4 cases

BACKGROUND

The radiopacity of ingested substances may serve as a clue to the presence of particular compounds, as this characteristic varies considerably among medications and household products. Tablet conglomerations are also variably radiopaque. We report 4 cases of clomipramine poisoning associated with formation of radiopaque masses, believed to be clomipramine, in the area of the stomach.

CASE REPORTS

Four patients were admitted to the Toxicological Intensive Care Unit after ingestions of, respectively, 8.5 g (180 tablets of mixed strength), 7.5 g (100 tablets), 10.5 g (140 tablets), and 4.5 g (60 tablets) of clomipramine, along with other sedatives and antipsychotics. In each case, a rounded density was observed in the gastric area on plain chest radiograph. The hospital courses of each patient were marked by tachycardia, hypotension, QRS and QT prolongation, seizures, and decreased mental status. Three of 4 patients underwent unsuccessful endoscopy to remove tablet fragments and subsequently suffered gastrointestinal hemorrhage requiring transfusion. All patients were discharged recovered from the hospital.

DISCUSSION

Clomipramine, a potent tricyclic antidepressant, has been previously reported to be nonradiopaque, and has not been reported to induce formation of concretions. These cases suggest that massive ingestions of clomipramine may form bezoars which are radiopaque and may be associated with serious toxicity. Careful consideration should be given prior to the use of gastric endoscopy for the retrieval of tablet fragments since significant hemorrhage, attributed to the procedure itself rather than to clomipramine toxicity, may ensue.

[Thrombus of the aortic arch: an unusual pathology in intensive care]

A 54-year-old patient was admitted to the intensive care unit for voluntary drug intoxication with zolipidem (Stilnox), dimenhydrinate (Mercalm), and oestradiol 17 beta (Oromone). Four hours after the admission the patient was comatose. Cerebral computerized tomodensitometry demonstrated multiple zones of ischaemia. Transoesophageal echocardiography was performed 12 hours after the arrival of the patient and revealed a mobile thrombus of the aortic arch. The remainder of the visualized aortic arch did not present atherosclerotic plaque. Secondarily, ischaemia of the right superior limb was diagnosed probably cause by emboli originating in the aortic thrombus appeared. The patient died three days later after her arrival, because of neurologic sequelae of the cerebral embolic events. This clinical case underlines the concept that the diagnosis of drug intoxication must remain a diagnosis of elimination. The thrombosis of the aortic arch is a rare pathology in intensive care units. In the presence of unexplained ischaemic stroke and an peripheral emboli, the thrombosis of the aortic arch should be suspected.

Fatality caused by a combined trimipramine-citalopram intoxication

A 53-year-old woman who was diagnosed as suffering from depression was found dead in her bed. The autopsy revealed no morphological changes sufficient to explain death. Toxicological analysis was performed and the drugs trimipramine (2.33 mg/l), citalopram (4.81 mg/l) and zolpidem (0.07 mg/l) were identified in the femoral blood. A combined drug intoxication resulting in synergistic effects to cardiovascular disorders was proposed as the cause of death. An acute overdose and suicide was suggested by calculation of the parent drug to main metabolite ratios in femoral blood and liver tissue. The trimipramine to desmethyltrimipramine ratios were calculated to be 2.06 and 3.18, the citalopram to desmethylcitalopram ratios were 1.96 and 2.02.

GC/MS determination of zolpidem in postmortem specimens in a voluntary intoxication

An ingestion of an unknown quantity of Ivadal (zolpidem) tablets in a case of drug abuse is described. The authors report a new and fast method of analysing and determining the zolpidem concentration in postmortem specimens. Quantitation of zolpidem was performed by ethyl acetate extraction from alkalinized body fluids before GC/MS analysis. The analyses were performed without any complex sample clean-up steps and with little sample material. Postmortem concentrations of zolpidem in body fluids are given. The proposed method is a rapid procedure of analysis in cases of deliberate poisoning with the sedative-hypnotic drug, zolpidem.

Acute zolpidem overdose--report of two cases

This report describes two cases of acute zolpidem overdose. The decedent in the first case was a 36-year-old female found dead in bed in her secured home. She had a history of psychiatric illness, including paranoid disorder, depression with panic episodes, and post-traumatic stress disorder. She was treated with risperidone and sertraline. Nine months prior to her death, the decedent was also prescribed zolpidem (Ambien). The postmortem examination revealed white foam within the larynx and upper trachea, which is indicative of pulmonary edema. Toxicological analyses of the urine showed the presence of caffeine, risperidone, and zolpidem. Subsequent quantitation of postmortem iliac serum revealed 5.6 microg/L of 9-hydroxyrisperidone and the following zolpidem concentrations: blood (subclavian), 4.5 mg/L; blood (iliac), 7.7 mg/L; vitreous humor, 1.6 mg/L; bile, 8.9 mg/L; urine, 1.2 mg/L; liver, 22.6 mg/kg; and gastric contents, 42 mg. The second case involved a 58-year old female, also found dead in bed, with white foam around her mouth. The decedent had a 25-year history of hypertension and mental illness--manic depression and schizophrenia. She was medicated with carbamazepine, naproxen, risperidone, and zolpidem. The postmortem examination revealed cardiomegaly, pulmonary edema, hepatomegaly, mild coronary atherosclerosis, and no signs of trauma. Toxicological analyses of the urine showed the presence of zolpidem and carbamazepine and metabolite. Zolpidem concentrations were as follows: blood (iliac), 1.6 mg/L; vitreous humor, 0.52 mg/L; bile, 2.6 mg/L; liver, 12 mg/kg; and gastric contents, 0.9 mg. The zolpidem blood concentrations of these cases are consistent with those of the previously published fatalities. The blood/vitreous humor ratios of zolpidem were 2.81 (subclavian) and 4.81 (iliac) in the first case and 3.08 (iliac) in the second case. These ratios, along with the sampling times of blood and vitreous humor for both cases, are not conclusive to indicate a definitive presence or absence of postmortem drug redistribution of zolpidem. The cause of death for both cases was determined to be acute zolpidem overdose, and manner of death was suicide.

A fatality involving zolpidem

An elderly woman residing in an independent-living retirement community was found dead in the bathtub. She had a history of depression and was prescribed Ambien (generic name zolpidem) for the treatment of insomnia. Two empty prescription bottles of Ambien were found; both were for 10-mg tablets with a total quantity of 60. A postmortem examination was conducted, and blood, urine, and gastric contents were submitted for toxicology screening. The cause of death was drowning. The only remarkable toxicology finding was zolpidem. Quantitative analysis by gas chromatography-mass spectrometry determined the following concentrations of zolpidem: blood, 7.9 micrograms/mL and urine, 4.1 micrograms/mL. A total of 7 mg unabsorbed zolpidem was found in the gastric contents. Our findings report the highest blood concentration of zolpidem reported to date and corroborate other studies that imply that death due solely to overdosage of zolpidem is an unlikely occurrence.

Emergency department use of flumazenil prior to poison center consultation

We studied the frequency of use of flumazenil by emergency departments in our region and compared it to recommendations made by specialists in poison information at our poison control center. For a 5-mo period, we prospectively collected cases involving benzodiazepines or zolpidem. Data was documented only from calls from emergency departments. Emergency department personnel were asked the following: If given, the dose and frequency, contraindications, and adverse reactions. Each case was followed to completion. Flumazenil was not given in 55 cases. Of the remaining 14 cases in which it was given, 10 of the cases received flumazenil prior to poison control center consultation. We noted 1 case of dizziness. Ten cases given flumazenil had contraindications (eg ethanol abuse or possible seizurogenic coingestants). Despite possible contraindications, flumazenil was given 10/14 times (71%) prior to calling the poison control center. These results point to potential overuse of this antidote where contraindications or cautions are suspected in the overdosed patients. Our study suggests that when flumazenil use is contemplated by an emergency department physician, a poison control center consult may have a contrary recommendation.

Zolpidem (Ambien): a pediatric case series

BACKGROUND

In 1993, the nonbenzodiazepine sedative-hypnotic zolpidem tartrate (Ambien) was approved for use in the US. Zolpidem has an imidazopyridine structure and possesses a rapid onset of action and a short half-life. The toxic threshold and profile have not been well established in the pediatric population.

METHODS

All pediatric zolpidem exposures reported to a regional poison information center over 24 months were reviewed retrospectively from the American Association of Poison Control Centers Toxic Exposure Surveillance System data collection forms.

RESULTS

Twelve pediatric zolpidem exposures were reported. Seven were unintentional (ages 20 mon-5 y) and five were intentional misuse/suicide (ages 12-16 y). The regional poison information center was contacted within 1 h in ten cases with onset of symptoms within 10 to 60 min (mean 31.6 min). One child had no effect with 2.5 mg. As little as 5 mg caused symptoms with minor outcome in six unintentional ingestions (5-30 mg). Minor to moderate symptoms were reported 1-4 h after intentional ingestions (12.5-150 mg). The duration of symptoms in the unintentional cases ranged from less than 60 min up to 4 h (mean 2.4 h) and 6-10 h (mean 7.5 h) in the intentional exposures. Treatment consisted of observation (4), syrup of ipecac (1), lavage and activated charcoal (1), activated charcoal alone (5), and unknown (1).

CONCLUSION

Due to the very rapid onset of central nervous system symptoms in children, emesis is not a treatment option. Supportive care, activated charcoal in large ingestions, and observation until symptoms resolve may be sufficient in most pediatric cases.

[Acute overdose of Zolpidem (Stilnox)]

Zolpidem (Stilnox), an imidazopyridine derivative, is a strong sedative with minor myorelaxant and anticonvulsant properties which exhibits high-affinity binding at a benzodiazepine-receptor subtype. Although the structure of zolpidem differs from the benzodiazepines, the acute toxicity of zolpidem has generally been compared to triazolam (Halcion) and midazolam (Dormicum). 5 years after introduction of zolpidem to the Swiss market we have therefore retrospectively analyzed 91 well documented cases of acute zolpidem intoxication reported to the Swiss Toxicological Information Center. Furthermore, 54 single-drug poisonings with zolpidem were compared with 53 triazolam and 55 midazolam intoxications observed over the same time period. 0.01-0.02 g of zolpidem is the recommended therapeutic dose. But only mild symptoms were observed in acute single-drug poisonings with zolpidem up to 0.6 g. Patients mainly suffered from somnolence. Only one anorectic patient became comatose after ingestion of 0.6 g zolpidem. The acute toxicity of zolpidem was markedly less pronounced than that of the short-acting benzodiazepines triazolam and midazolam. With forty-fold the therapeutic dose no severe symptoms occurred in patients with zolpidem single-drug poisonings, while coma was encountered in 4 cases with triazolam (11% of patients) and 4 cases with midazolam (10%). While only the patient mentioned above was reported to be comatose after overdosing with zolpidem, 6 (11%) and 8 (15%) comatose patients were observed in triazolam and midazolam single-drug poisonings, respectively. On the other hand, in combined intoxications with other CNS active drugs or ethanol a zolpidem dose as low as 0.1-0.15 s induced coma in some patients, even if the amount of the additionally ingested drugs in itself would not have caused a comatose state. Flumazenil (Anexate) was an effective antidote in mono- and combined intoxications involving zolpidem. In conclusion, our results indicate that zolpidem single-drug poisonings are generally benign and require no specific therapeutic measures. In combined intoxications, however, patients may develop coma at relatively low zolpidem doses and should therefore be monitored for approximately 24 hours. If necessary, disturbances of consciousness can be successfully treated with flumazenil.

Acute overdose of zolpidem

Zolpidem (Ambien) is an imidazopyridine hypnotic recently introduced in the USA. We report a case of a fatal overdose of Ambien. A 68-year-old female ingested at least 30 tablets of 10 mg Ambien (300 mg). She was found dead at home. Toxicological analyses revealed blood concentration of 4.1, 19.3 and 2.3 micrograms/ml of zolpidem, meprobamate and carisoprodol, respectively.

Ingestion of poison hemlock (Conium maculatum)

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Leucaena toxicosis and its control in ruminants

Leucaena (Leucaena spp., especially L. leucocephala) is an arboreal, tropical legume that ranges into the cool subtropics and equatorial elevations up to 1,000 m. One of its uses includes forage for livestock, but introduction of leucaena outside its indigenous range often has led to acute and chronic toxicosis. The major toxic constituents of leucaena are the nonprotein free amino acid mimosine and its ruminal degradation product, 3-hydroxy-4(1H)-pyridone (3,4-dihydroxypyridine; 3,4-DHP). Leucaena also contains appreciable quantities of condensed tannins. In ruminants, mimosine is a depilatory agent and 3,4-DHP is a potent goitrogen. In the 1980s, Australian workers demonstrated that the geographical limits of leucaena toxicosis were due to the absence of ruminal bacteria capable of degrading 3,4-DHP, and successfully introduced 3,4-DHP degrading ruminal bacteria from a Hawaiian goat into goats and cattle in Australia. Simple in vitro screening methods have been developed for detection of 3,4-DHP degraders in ruminal samples and feces. Also, several strains of 3,4-DHP degrading ruminal bacteria have been characterized and have been given the genus and species designation, Synergistes jonesii. Ruminal inoculation with ruminal contents from adapted animals, enriched cultures of 3,4-DHP-degrading ruminal bacteria, and pure cultures of S. jonesii have all been used successfully to establish ruminal populations that are capable of degrading 3,4-DHP and preventing leucaena toxicosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute zolpidem poisoning--analysis of 344 cases

Zolpidem is a new short acting hypnotic agent, first launched in France in 1988. Three hundred forty-four cases of intentional acute overdoses are reviewed retrospectively. Patients were predominantly female (70%) in their third or fourth decade. Ingested doses of zolpidem ranged between 10 and 1400 mg (one pack or less in 80%). Half of the patients ingested other substances (psychotropic drugs and alcohol) concomitantly. Signs of intoxication were observed in two thirds of the population but could be attributed to zolpidem in only 105 cases: drowsiness (N = 89) occurred at doses of 140 to 440 mg; coma (N = 4) or respiratory failure (N = 1). Other symptoms were rare (excepted vomiting, N = 7). Of the rare electrocardiographic or biological abnormalities, none appeared to be directly related to zolpidem. Therapy for intoxication was usually limited to supportive measures and/or gastric lavage. Symptoms of intoxication rapidly remitted in 91% of cases. Three percent of patients with multiple drug ingestion recovered despite severe complications during intensive care. Fatalities were reported for 6% but could not be directly linked to zolpidem. Previous published reports are confirmed: zolpidem acute overdose is generally benign and requires no specific therapeutic measures.

A fatality involving two unusual compounds--zolpidem and acepromazine

A fatality due to ingestion of zolpidem, a recently developed nonbenzodiazepine hypnotic, and acepromazine, a phenothiazine sedative used in veterinary practice, is reported. Both drugs were identified and quantified using high-performance liquid chromatography with diode-array detection. Zolpidem and acepromazine blood concentrations were 3.29 and 2.40 micrograms/ml, respectively. It is the first report of a death involving either of these two drugs. The results are discussed in the light of the existing literature and may suggest a reciprocal potentiation of the toxic effects of zolpidem and phenothiazines.

High-performance liquid chromatographic assay with diode-array detection for toxicological screening of zopiclone, zolpidem, suriclone and alpidem in human plasma

A high-performance liquid chromatographic assay with diode-array detection has been developed for the toxicological screening of the newly developed non-benzodiazepine hypnotics and anxiolytics zopiclone, zolpidem, suriclone and alpidem. After single-step liquid-liquid extraction of plasma at pH 9.5 using chloroform-2-propanol-n-heptane (60:14:26, v/v), the substances are separated on a Nova-Pak C18 4-microns column (300 mm x 3.9 mm, I.D.), with methanol-tetrahydrofuran-pH 2.6 phosphate buffer (65:5:30, v/v) as the mobile phase (flow-rate 0.8 ml/min). Full ultraviolet spectra from 200 to 400 nm are recorded on-line during the entire analysis and may be automatically compared to spectra stored in a library. The retention times of the four drugs are 4.05 min (zopiclone), 4.66 min (zolpidem), 6.74 min (suriclone) and 10.97 min (alpidem). The analysis is performed in 15 min. The method is simple, rapid and highly specific. It is the first assay to be described for convenient screening of cyclopyrrolones and imidazopyridines.

Determination of zolpidem, a new sleep-inducing agent, and its metabolites in biological fluids: pharmacokinetics, drug metabolism and overdosing investigations in humans

For the determination of zolpidem, a new sleep inducer, and its metabolites in human plasma and urine, three methods were developed that are suitable for pharmacokinetics, drug metabolism and overdosing investigations. The methods used for pharmacokinetic and drug metabolism studies are based on column-switching high-performance liquid chromatography; they do not require any sample manipulation because the plasma or diluted urine is injected into a pre-column where clean-up and preconcentration take place. The analytes are transferred by valve-switching to the C18 analytical column for chromatography. To investigate overdose cases, urine samples only are used: the method is simple, because the diluted urine can be injected directly into the analytical column (phenyl type). This allows the identification and quantification of the principal urinary metabolite of zolpidem, the unchanged drug being practically undetectable. All the methods use fluorescence detection, which affords high sensitivity and selectivity. It is necessary to use a method capable of the determination of metabolites even if these are apparently pharmacologically inactive, because in different physiopathological populations the qualitative and quantitative metabolic profiles of zolpidem could be different. The method designed for the investigation of (accidental or deliberate) overdose cases is, as required on such occasions, simple and rapid, with good selectivity with respect to commonly prescribed psychotropic drugs.

HPLC quantification of zolpidem and prothipendyl in a voluntary intoxication

Zolpidem, a recently developed sleep inducer, and prothipendyl, a neuroleptic azaphenothiazine, were involved in a voluntary intoxication along with ethanol. After administration of flumazenil, a specific benzodiazepines antagonist, respiratory depression was corrected. HPLC with UV detection methods after selective extraction were developed to measure simultaneously prothipendyl and zolpidem without flumazenil interaction. These methods could be applied in drug monitoring and in emergency toxicology.

Zolpidem intoxication mimicking narcotic overdose: response to flumazenil

Zolpidem is a recently introduced sleep-inducer which is thought to act on the central-type benzodiazepine receptors. This observation is the first report of drug poisoning with this compound. The toxic response was characterized by the development of a profound but short-lasting coma, associated with pin-point pupils and respiratory depression, as observed in a narcotic overdose. These clinical signs were not influenced by the administration of naloxone, but responded dramatically to flumazenil. Some analytical data on zolpidem toxicokinetics are presented.

[Outcome of acute renal failure caused by voluntary ingestion of Cortinarius orellanus]

Orellanin poisoning is characterized by an acute renal failure which can be lethal if the appropriate treatment is not given. A 31-year old woman was admitted to hospital 10 days after she had deliberately ingested 2 raw carpophores of the mushroom Cortinarius orellanus. Acute renal failure (creatininaemia 1,100 mumol/l) developed, requiring 6 sessions of haemodialysis, one of plasmapheresis and the administration of diltiazem and aminoacids. Plasma and tissue assays of orellanin, the mushroom's toxin, were performed by two-dimensional thin layer chromatography. Before haemodialysis and 10 days after ingestion of the poison, the plasma contained orellanin. Eighteen months after the attempted suicide, the plasma creatinine level was 181 mumol/l.

Intoxication by Cortinarius orellanus: detection and assay of orellanine in biological fluids and renal biopsies

A woman suffering from acute tubulo-interstitial nephritis was admitted to the hospital ten days after deliberate intoxication by ingestion of Cortinarius orellanus. Orellanine, the main toxin responsible for orellanine poisoning, was detected in biological fluids and renal biopsies. It was assayed by direct spectrofluorimetry on two-dimensional thin-layer chromatograms after specific photodecomposition into orelline. The orellanine concentration was 6.12 mg/l in the plasma (10 days after ingestion). Orellanine levels in renal biopsies were 7 micrograms per 25 mm3 of the first biopsy (13 days after ingestion) and 24 micrograms per 8 mm3 of the second biopsy (6 months later).

Nyquil-associated liver injury

Acetaminophen, a commonly used medication, is present in many over-the-counter remedies. In recent years, its potential to cause severe liver injury has been increasingly appreciated. Chronic abusers of alcohol may be particularly susceptible to hepatotoxicity from acetaminophen. We report two cases of unintentional liver injury associated with ingestion of Nyquil, a liquid cold remedy containing acetaminophen and 25% alcohol.

Effect of intrastriatal and intranigral administration of synthetic neuromelanin on the dopaminergic neurotoxicity of MPTP in rodents

Previous studies showed that the neurotoxin MPTP and its toxic metabolites bind with high affinity to neuromelanin (NM). Therefore, the presence of NM in human and primate but not in rodent substantia nigra, theoretically may be responsible for the species-selective dopaminergic (DA) toxicity of MPTP. We measured DA levels in rodent striatum 7 days after an acute single challenge with MPTP (40 mg/kg, s.c.) given alone or 24 h following unilateral intrastriatal injections of synthetic DA-NM in mice and intrastriatal or intranigral pigment administration in rats. Ipsilateral striatal DA levels were unaffected in control rodents treated with unilateral intrastriatal or intranigral DA-NM. In mice, systemic MPTP produced marked striatal DA depletions which were mildly increased in the striata given prior DA-NM injections. In rats, a species resistant to MPTP, administration of toxin did not affect striatal DA levels. However, after pretreatment with unilateral intrastriatal DA-NM, MPTP induced mild DA falls in ipsilateral striata. By contrast, intranigral administration of DA-NM followed by MPTP, did not alter ipsilateral striatal DA in rats. The findings suggest that intrastriatal DA-NM in mice and rats may augment or initiate, respectively. MPTP-induced damage to sensitive DA-nerve-terminals perhaps by its action as a depot for binding and protracted release and action of the toxin. Lack of effect of intranigral DA-NM which is retained extraneuronally suggests that role of NM in the toxicity of MPTP may depend on its location within DA cell bodies in the nigra.

Acute ultrastructural and behavioral effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice

Acute actions of MPTP on behavior and on neostriatal ultrastructure were examined in young C57 Black mice. Autonomic, motor, and toxic effects of MPTP exhibited dependence on dose (20-40 mg/kg) and time during the first 4 h after subcutaneous injection. The ultrastructure of the neostriatum was altered very quickly (2-24 h) after single injections of MPTP. Darkened glial processes were found within 2-8 h, followed by dark degeneration of synaptic boutons, especially those making small symmetric synapses. More rarely, swollen axons and postsynaptic degeneration were also observed.

Rhabdomyolysis complicating doxylamine overdose

A 16-year-old male presenting with anticholinergic symptoms was found to have hematuria and oliguria. Evaluation of the patient revealed a serum creatinine of 2.2 mg/dl, myoglobinuria, and a creatine phosphokinase (CPK) level of 78, 750 IU/l with 99 percent fraction 3 isoenzyme. A toxic screen showed the presence of doxylamine, an antihistamine of the ethanolamine class, at a level of 75 times therapeutic. The patient did not have a history of trauma or seizures. The extremely high CPK level with the doxylamine overdose suggests that doxylamine may be associated with nontraumatic rhabdomyolysis. This is the first case report of rhabdomyolysis being associated with an antihistamine overdose.

MPTP-induced up-regulation of in vivo dopaminergic radioligand-receptor binding in humans

We measured in vivo dopaminergic receptor binding using positron emission tomography and 18F-spiperone in an untreated symptomatic subject with MPTP-induced parkinsonism. Our technique determines four variables related to entry of 18F-spiperone into brain tissue and subsequent binding to receptors: (1) the combined forward-rate constant k1' (equal to the product of the maximum number of available specific binding sites, Bmax, times the association rate constant [ka] of 18F-spiperone and receptor); (2) the binding site dissociation rate constant k-1; (3) the free fraction of radioligand not specifically bound in brain tissue, f2; and (4) the regional permeability-surface-area product (PS) of the blood-brain barrier for spiperone. PS and f2 in the patient were not different from that of 10 normal volunteers, whereas the combined forward-rate constant (left caudate: k1' = 67.6 sec-1, normal = 0.140 +/- 0.056) and the dissociation rate constant (left caudate: k-1 = 0.116 sec-1, normal = 0.000339 +/- 0.000149) were evaluated. These findings provide potential new insights not only into the pathophysiology of this disease but into the clinical importance of dopamine receptor function as well.

Poisoning with over-the-counter doxylamine preparations: an evaluation of 109 cases

One hundred and nine cases of monointoxication with doxylamine were evaluated with respect to age distribution, amount ingested, plasma level, and clinical symptomatology. The age of 60% of the patients ranged between 16 and 30 years. In about 60% of the cases 10 to 40 times a single therapeutic dose (25 mg) was ingested. Doxylamine plasma concentrations exceeded the maximum plasma level after a therapeutic dose by a factor of 10 to 40 in two-thirds of cases. The most frequent symptoms included impaired consciousness, seizures, tachycardia, mydriasis and a 'psychosis' similar to that in catatonic stupor. A serious complication may be rhabdomyolysis with subsequent impairment of renal function and acute renal failure. No symptoms were observed in 39% of the patients. No correlation was found between the amount ingested or doxylamine plasma level and the clinical symptomatology. Primary detoxication included gastric lavage, administration of activated charcoal and sodium sulfate. Regarding the high frequency of doxylamine overdose and its possible complications the question arises as to whether doxylamine-containing preparations should be subjected to prescription.

Effects of MPTP poisoning on central somatostatin and substance P levels in the mouse

The effects of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) on the levels of the neuropeptides somatostatin and substance P, were examined in various brain regions of C57 mice. Two weeks after injections of MPTP (2 X 30, 2 X 40 and 2 X 50 mg/kg i.p.) a dose-dependent decrease in striatal catecholamine levels was observed. There was also a dose-dependent increase in nigral somatostatin immunoreactivity and no reduction in striatonigral substance P levels. These results are in contrast with the changes observed in peptide levels in post-mortem Parkinson's brains.

Saccade responses to dopamine in human MPTP-induced parkinsonism

Depletion of dopamine content in the substantia nigra resulting from 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) toxicity produces parkinsonism. Management of 3 patients with MPTP-induced parkinsonism required drug holidays during which there was a state of dopamine depletion followed by dopamine replacement. We used this opportunity to study the effect of the selective loss of pars compacta dopaminergic cells on vertical and horizontal saccade (fast) eye movements. During the drug holidays, visually guided saccades were hypometric and had long latencies but retained a normal saccade velocity-amplitude relationship. Dopamine agonists or precursors improved the accuracy and reaction times of saccades in all directions, but not their velocity. Two of the three patients also had intermittent blepharospasm during dopamine depletion. During the episodes of blepharospasm, saccade responses became slow eye movements. MPTP causes a dopaminergic-responsive disorder of saccade initiation that is similar to idiopathic parkinsonism. The inhibition of voluntary eyelid opening during MPTP-induced blepharospasm further increases this impairment of fast eye movements and altered saccade velocity, presumably via the pars reticulata of the substantia nigra.