Use of neostigmine for the management of drug induced ileus in severe poisonings

INTRODUCTION

Effective whole bowel irrigation may be difficult in the presence of drug-induced ileus. Neostigmine, which inhibits the enzymatic degradation of acetylcholine, has been suggested to improve drug-induced ileus. We present two poisoning cases in which neostigmine was used to facilitate gut decontamination complicated by ileus.

CASE REPORTS

A 47-year-old woman, after overdose with sodium valproate, venlafaxine, and ibuprofen, developed ileus that prevented whole bowel irrigation. Neostigmine, 2.5 mg intravenously followed by 1.25 mg three hours later, led to improved bowel transit and successful whole bowel irrigation. A 25-year-old man developed ileus after overdose with venlafaxine, dothiepin, and ethanol. Neostigmine administration led to improved intestinal motility and successful whole bowel irrigation.

DISCUSSION

We demonstrate facilitated gut decontamination temporally associated with administration of neostigmine in two patients judged to have drug-induced ileus following overdose. No significant adverse events related to neostigmine were observed.

Take-home naloxone to reduce heroin death

BACKGROUND

This paper reviews the relevant literature related to the distribution of take-home naloxone.

METHODS

A Medline search was conducted on articles published between January 1990 and June 2004 to identify scientific literature relevant to this subject. Those publications were reviewed, and from them other literature was identified and reviewed.

RESULTS

The prevalence, pathophysiology and circumstances of heroin overdose, and also bystander response are included in this review. Naloxone peer distribution has been instituted to varying degrees in the United States, Italy, Spain, Germany and the United Kingdom.

CONCLUSION

At this point the evidence supporting naloxone distribution is primarily anecdotal, although promising. Although the distribution of naloxone holds promise for further reducing heroin overdose mortality, problems remain. Naloxone alone may be insufficient in some cases to revive the victim, and cardiopulmonary resuscitation (CPR), especially rescue breathing, may also be needed. A second dose of naloxone might be necessary. Complications following resuscitation from overdose may infrequently need in-hospital care. Mortality from injecting without anyone else present will be unaffected by take-home naloxone. Take-home naloxone should be studied in a rigorous scientific manner.

The effect of HIV infection on overdose mortality

OBJECTIVES

To quantify the association of HIV infection with overdose mortality and explore the potential mechanisms.

DESIGN

A prospective cohort study.

METHODS

A total of 1927 actively injecting drug users who were HIV seronegative at baseline, of whom 308 later HIV seroconverted, were followed semi-annually for death from 1988 to 2001. Survival analyses using marginal structural and standard Cox models were used to evaluate the effect of HIV infection on the risk of overdose mortality.

RESULTS

Overdose death rates were higher in HIV-seropositive than HIV-seronegative drug users: 13.9 and 5.6 per 1000 person-years, respectively (P < 0.01). The hazard ratio (HR) was 2.54 [95% confidence interval (CI) 1.47, 4.38] for the marginal structural model and 2.06 (95% CI 1.25, 3.38) for the standard Cox model, both adjusted for demographics, drug injection characteristics, alcohol abuse, substance abuse treatment, and sexual orientation. Adjusting for possible time-varying mediators (i.e. drug use, medical conditions and healthcare access) in extended marginal structural models reduced the effect of HIV on overdose mortality by 30% (HR 1.82, 95% CI 1.01, 3.30). Abnormal liver function was associated with a higher risk of overdose mortality (HR 2.00, 95% CI 1.05, 3.84); adjustment for this further reduced the effect of HIV on overdose mortality.

CONCLUSION

HIV infection was associated with a higher risk of overdose mortality. Drug use behavior, systematic disease and liver damage associated with HIV infection appeared to account for a substantial portion of this association. The data suggest a group to target with interventions to reduce overdose mortality rates.

Androgen dependence in hamsters: overdose, tolerance, and potential opioidergic mechanisms

Anabolic steroids are drugs of abuse. However, the potential for steroid reward and addiction remains largely unexplored. This study used i.c.v. testosterone self-administration and controlled infusions of testosterone or vehicle in hamsters to explore central mechanisms of androgen overdose. Forty-two hamsters used nose-pokes to self-administer 1 microg/microl testosterone i.c.v. 4 h/day in an operant chamber. During 1-56 days of androgen self-administration, 10 (24%) hamsters died. Deaths correlated with peak daily intake of testosterone. Of the hamsters that self-administered a peak intake of <20 microg/day, there was 100% survival (10/10). Survival decreased to 86% (19/22) when daily testosterone intake peaked at 20-60 microg/day. Only 30% (three of 10) survived when daily testosterone intake exceeded 60 microg/day. Deaths are not due to volume or vehicle because i.c.v. infusions of 80 mul vehicle had no effect. Testosterone overdose resembles opiate intoxication. When male hamsters received infusions of 40 microg testosterone, locomotion (25.1+/-18.8 grid-crossings/10 min), respiration (72.7+/-5.4 breaths/min) and body temperature (33.5+/-0.4 degrees C) were significantly reduced, compared with males receiving vehicle infusions (186.1+/-8.1 crossings/10 min, 117.6+/-1.0 breaths/min, 35.9+/-0.1 degrees C, P<0.05). However, males developed tolerance to continued daily testosterone infusion. After 15 days, locomotion (170.2+/-6.3 crossings), respiration (118.4+/-1.3 breaths/min), and body temperature (35.3+/-0.3 degrees C) in testosterone-infused males were equivalent to that in vehicle controls (P>0.05). The depressive effects of testosterone infusion are blocked by the opioid antagonist, naltrexone. With naltrexone pre-treatment (10 mg/kg s.c.), locomotion (183.7+/-1.8 crossings/10 min), respiration (116.9+/-0.3 breaths/min), and body temperature (36.1+/-0.4 degrees C) during testosterone infusion were equivalent to vehicle controls. Likewise, naltrexone prevents the reinforcing effects of i.c.v. testosterone self-administration. These results indicate that testosterone at high doses causes central autonomic depression, which may be a factor in deaths during self-administration. As well, the depressive effects of large quantities of testosterone may be mediated, at least in part, by an opioidergic mechanism.

Are one or two dangerous? Tricyclic antidepressant exposure in toddlers

Tricyclic antidepressants (TCA), increasingly prescribed for multiple indications in children and adults, are responsible for many pediatric poisonings. Though the majority of TCA exposures in this age group remain asymptomatic, several reports in the English language literature reveal significant morbidity as well as fatalities in toddlers, primarily from imipramine and desipramine. These few cases indicate that doses of 10-20 mg/kg (one to two pills) have the potential for toxicity and fatalities. More recent studies have focused on the relative safety of small exposures suggesting that with doses less than 5 mg/kg the patient may be safely observed at home. Though further studies are necessary to determine the exact dosing that places the child at risk, the authors recommend a 6-h Emergency Department observation period for children who ingest more than 5 mg/kg of most TCAs, as clinical toxicity becomes evident within this time frame.

The administration of N-acetylcysteine causes a decrease in prothrombin time in patients with paracetamol overdose but without evidence of liver impairment

OBJECTIVE

To explore the effect of intravenous N-acetylcysteine (NAC) on the prothrombin time (PT) in patients with paracetamol overdose and persistent normal liver profile.

MATERIALS AND METHODS

This retrospective case series study examined all admissions with a diagnosis of paracetamol poisoning in a tertiary hospital between 1989 and 2002. Patients were included if they had ever received NAC infusion, had no biochemical evidence of liver damage, and had more than two measurements of PT. Patients who had also ingested other drugs were excluded.

RESULTS

Of 65 admissions wtih paracetamol poisoning, 18 patients (10 men) met the inclusion criteria. The median age was 29 years, and the median quantity of paracetamol ingested was 186 mg/kg. The mean number of PT measurements per patient was 4.8. The baseline PT (as a percentage) 8.6 h after paracetamol ingestion was 89.6%. During NAC infusion the PT fell in all patients (range, 4.8-53.4% relative to baseline; P < 0.0001) at 14 h. The PT was less than 60% in 28% of the patients. Eight hours after the initiation of NAC there was a 16% fall in PT (range, 4.3-34%; P < 0.0001). At the end of NAC infusion all PTs returned to values close to baseline. Nine patients were hospitalized.

CONCLUSIONS

In patients with paracetamol overdose without evidence of liver damage a marked decrease in PT often occurs, which seems to be due to the overload of NAC infused at the beginning of treatment. This particular feature should be noted in clinical practice guidelines as a potentially misleading indicator of the development of severe liver dysfunction.

Atypical experience: a case series of pediatric aripiprazole exposures

BACKGROUND

Aripiprazole is a new psychotropic agent that possesses a unique pharmacologic profile. The drug demonstrates mixed dopamine and serotonin agonist-antagonist activity and has been labeled a third-generation antipsychotic and dopamine-serotonin system stabilizer. Overdose experience is limited, especially in pediatrics.

CASE SERIES

Of five pediatric cases identified, toxicity was mainly evident in younger patients. A 2-year-old who ingested 40 mg experienced vomiting and significant lethargy lasting approximately 30 h. A 6-year-old who received two doses of aripiprazole therapeutically experienced lethargy, drooling, and flaccid facial muscles which improved with diphenhydramine. Two adolescents remained asymptomatic despite doses of 120 mg and 300 mg while a third adolescent with an unknown dose experienced transient lethargy.

CONCLUSION

Aripiprazole is capable of producing marked lethargy and gastrointestinal upset in pediatric patients. Adolescents in this series experienced only minor, if any, clinical effects. Major clinical effects, i.e., seizures, dysrhythmias, were not reported in this series.

Selected clinical aspects of acute intoxication with baclofen

Baclofen is a lipophilic analogue of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in central nervous system. The aim of the study was to evaluate some clinical aspects of acute intoxication with baclofen. Fifty two patients (37 females and 15 males) aged from 14 to 58 (mean 30.6 +/- 13.7) years were analyzed. Patients were admitted to the Clinic of Internal Diseases and Acute Poisonings Medical University of Gdańsk and the Centre of Acute Poisonings of Praski Hospital in Warszawa during the years 1996-2004 because of suicidal intoxication with baclofen. The doses of baclofen varied from 100 to 1500 (mean 444.8 +/- 317.8) mg. There were twenty eight patients (53.8%) in deep coma (III and IV grade of Matthew scale). Acute respiratory failure which required mechanical ventilation was observed in 18 cases (34.6%). Cardiac abnormalities included bradycardia (36.5%), hypertension (32.7%) and hypotension (3.8%). Toxic psychoses were observed in 6 cases (11.5%). The dosage of baclofen in patients with acute respiratory failure (ARF) was significantly higher than in patients without ARF. Treatment of patients with acute baclofen intoxication should take place in hospitals appropriately equipped which can provide artificial respiration.

Gamma-hydroxybutyrate (GHB) and gamma-butyrolactone (GBL): analysis of overdose cases reported to the Swiss Toxicological Information Centre

We analysed 141 cases of Gamma-hydroxybutyric acid (GHB) and Gamma-butyrolactone (GBL) intoxication reported by physicians to the Swiss Toxicological Information Centre between 1995 and 2003. GHB and GBL intoxication are associated with considerable morbidity. Multiple drug use is common. Overdosing frequently results in non-reactive coma, which accounts for the severity of the intoxication and the costs occasioned by management.

Pharmacological complications of the chronic baclofen infusion in the severe spinal spasticity. Personal experience and review of the literature

AIM

To evaluate the pharmacological complications and side effects of the chronic intrathecal baclofen infusion in patients suffering from intractable spinal spasticity in our Department as well as in the literature.

METHODS

The pharmacological complications and side effects observed at long-term follow-up in 25 patients with chronic intrathecal baclofen infusion are evaluated; the search of the literature complications was carried out in Medline and in Ingenta web sites.

RESULTS

We have been able to observe in our series 3 (12%) patients with hypotonia, 2 with impairment on erection (8%) and 1 (4%) with constipation; 5 (20%) patients showed also tolerance but only 1 (4%) needed a ''drug holiday''. In the literature the side effects range from 4% to 16%. Moreover the tolerance is reported from 3% to 15%. The overdose has been reported from 0% to 14%, while the syndrome of withdrawal is reported in 16 patients with 6 fatalities. In our series these two last complications were not observed.

CONCLUSIONS

Lethal pharmacological complications are rare and, if promptly diagnosed and treated, are reversible. Side effects of minor importance can impair the patient quality of live and needed to be adjusted to patient's requirements. This kind of therapy should be restricted to specialized centres.

Proper Dose, Preparation, and Storage of Botulinum Neurotoxin Serotype A

PURPOSE

The proper dose, preparation, and storage of the formulation of botulinum neurotoxin serotype A (botulinum toxin type A) that is available in the United States (Botox) are described.

SUMMARY

The recommended dose of botulinum toxin type A varies widely from 1.25 Units to 100 Units, depending on the site. Small initial doses are used for patients without previous treatment with botulinum toxin. Repeat injections often are required, and subsequent doses should be individualized based on response. Larger repeat doses often are used when the response to initial doses is insufficient. An antitoxin is available in the event of accidental poisoning. Botulinum toxin type A is reconstituted with preservative-free 0.9% sodium chloride. Therefore, it should be stored in a refrigerator and discarded if more than four hours elapse after reconstitution.

CONCLUSION

The safe and effective use of botulinum toxin type A requires the proper dose, preparation, and storage by trained personnel only.

Managing antidepression overdoses

Depression is a physiological disorder that is medically treated by increasing the bodily amount of one or all of the following neurotransmitters: serotonin, dopamine and norepinephrine. Although there are seven distinct classes of antidepressants, prehospital care professionals should at minimum be able to distinguish the monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and newer antidepressants that are none of these. Monoamine oxidase inhibitors have severe, potentially life-threatening interactions with a variety of medications, including the paramedic drug meperidine, as well as with many common foods. An overdose of tricyclic antidepressants can cause lethal cardiac irregularities. Tricyclics are toxic to children in very small doses. A patient who has overdosed on TCAs may be walking and talking when you first arrive, then quickly deteriorate and die before your eyes. The treatment for TCA overdose is sodium bicarbonate; refer to your medical direction for dosages and indications. A common indication of TCA overdose, secondary to the patient's having access to the drugs, is widening of the QRS complex to greater than 0.12 seconds. Serotonin syndrome is often the result of taking a new generation antidepressant, such as an SSRI, while there is still TCA or MAOI in the bloodstream.

Evaluation of lamotrigine toxicity reported to poison centers

BACKGROUND

Lamotrigine is an antiepileptic drug for the treatment of partial and generalized seizures as well as bipolar disorder. Limited published information exists describing the clinical effects of lamotrigine overdose.

OBJECTIVE

To examine the toxicity of exposures to lamotrigine utilizing national poison center data.

METHODS

Data on single-substance exposures to lamotrigine reported to the American Association of Poison Control Centers Toxic Exposure Surveillance System in 2000 and 2001 were retrospectively analyzed.

RESULTS

There were 493 cases that met the inclusion criteria. The majority of exposures occurred within the age groups 20-59 years old (n = 198, 40.2%), followed by </=4 years old (n = 173, 35.1%). Overall, the majority of patients (52.1%) exposed to lamotrigine in overdose experienced no toxic clinical effects. The most common clinical effects reported in overdose were drowsiness/lethargy (20.9%), vomiting (11%), nausea (5.1%), ataxia (4.9%), dizziness/vertigo (4.5%), and tachycardia (4.3%). Major clinical effects included coma (n = 6), seizures (n = 8), and respiratory depression (n = 3). Medical outcome was reported as minor in 150 (30.4%), moderate in 73 (14.8%), and major in 13 (2.6%) cases. There were no deaths.

CONCLUSIONS

These data demonstrate that the majority of patients exposed to lamotrigine in overdose experienced minor or no clinical effects. Although rare, serious effects can also occur.

Cocaine and the critical care challenge

OBJECTIVE

Cocaine, which first made its appearance >1,000 yrs ago, is now widely used throughout the world. The physiologic responses to cocaine may cause severe pathologic effects. This review highlights the many critical care challenges resulting from these effects.

DESIGN

Historical vignettes, epidemiologic factors, modes of preparation and delivery, and the physiologic and pharmacologic effects of these agents are presented.

SETTING

Cocaine causes intense vasoconstriction, which potentially causes damage to all organ systems. Examples of these toxicities are presented.

PATIENTS

The adverse multisystem responses to cocaine exposure produce organ failure, which challenges diagnostic accuracy and therapeutic intervention. Organ system failure involves the brain, heart, lung, kidneys, gastrointestinal tract, musculature, and other organs. These harmful effects are additive to preexisting organ dysfunction.

INTERVENTION

Recognition of associated cocaine injury alerts the physician that organ dysfunction is more likely to occur and to be more severe. Such anticipation helps plan for therapy in the critical care setting.

RESULTS AND CONCLUSIONS

Cocaine use is an expanding health hazard, despite intense governmental efforts to contain its distribution and use. Recognition of the signs and symptoms of cocaine toxicity help anticipate the subsequent organ dysfunction and implement earlier organ system support.

Massive Caffeine Overdose Requiring Vasopressin Infusion and Hemodialysis

INTRODUCTION

Massive caffeine overdose is associated with life-threatening hemodynamic complications that present challenges for clinicians. We describe the highest-reported serum concentration of caffeine in a patient who survived and discuss the first-reported use of vasopressin and hemodialysis in a caffeine-poisoned patient.

CASE REPORT

A 41-yr-old woman presented 3 h after ingesting approximately 50 g of caffeine. She subsequently underwent cardiopulmonary resuscitation and received multiple medications in an attempt to raise her blood pressure and control her heart rate without success. Vasopressin infusion increased her blood pressure to the point where hemodialysis could be performed. Despite ensuing multisystem organ failure, she survived and has made a complete recovery.

CONCLUSION

Hemodialysis and vasopressin infusions may be of benefit in the management of caffeine-intoxicated patients who fail to respond to standard therapies.

Pharmaceutical drug overdose case reports. From the World Literature

All pharmaceutical drugs have the potential to be misused or wrongly administered, which can result in toxic amounts of drug being ingested. To help you keep up-to-date with the latest data on outcomes and management of overdoses, both accidental and intentional, we have selected the following case reports recently published in the international medical literature and summarised in Reactions Weekly. Any claim of first report has been verified by a search of the Adisbase (a proprietary database of Adis International) and Medline. In addition, the World Health Organization (WHO) Adverse Drug Reaction database is also searched. This database, maintained by the Uppsala Monitoring Centre in Sweden, is the largest and most comprehensive adverse drug reaction source in the world, with information obtained from the National Centres of over 70 affiliate countries.

Adverse pulmonary vascular effects of high dose tricyclic antidepressants: acute and chronic animal studies

Overdose of tricyclic antidepressants, which inhibit cellular serotonin (5-HT) uptake, sometimes causes acute respiratory syndrome-like symptoms. Their acute and chronic cardiopulmonary actions, which might be implicated, utilising both in vivo and ex vivo animal studies, were investigated in this study. Acute amitriptyline (AMI), iprindole and imipramine caused dose-dependent prolonged rises in pulmonary artery pressure and oedema in anaesthetised cats in vivo. Acute AMI, in isolated ex vivo blood-perfused rat lungs, also caused dose-dependent sustained vasoconstriction, which could be attenuated with either calcium channel inhibition or a nitric oxide donor. It was demonstrated that the pressor effects of AMI were not due to release of histamine, serotonin, noradrenaline, or the activities of cycloxygenase or lipoxygenase. After AMI, hypoxic pulmonary vasoconstriction and the pressor actions of 5-HT and noradrenaline were diminished, possibly due to uptake inhibition. Activities of the endothelial-based enzymes, nitric oxide synthase and endothelin-converting enzyme, were undiminished. Large acute doses of AMI caused oedema with rupture of capillaries and alveolar epithelium. Chronic iprindole raised pulmonary artery pressure and right ventricle (RV)/left ventricle (LV) + septal (S) weight. Chronic AMI led to attenuation of the pressor action of 5-HT, especially when associated with chronic hypoxic-induced pulmonary hypertension. RV/LV+S weight increased, attributable to LV decline. The acute and chronic effects observed might have relevance to clinical overdose, while the attenuation of acute effects offers possible therapeutic options.

Ziprasidone: an atypical antipsychotic drug for the treatment of schizophrenia

BACKGROUND

Over the past decade, use of the atypical antipsychotic drugs clozapine, risperidone, olanzapine, and quetiapine has significantly changed the treatment of schizophrenia in the United States. The ability to make optimal drug choices will depend on determining whether there are clinically important differences between these drugs.

OBJECTIVE

This review describes ziprasidone, the most recently introduced antipsychotic drug. Its mechanism of action, pharmacokinetics, and adverse-effect profile are discussed, and the results of clinical efficacy trials are summarized.

METHODS

This review of ziprasidone is based on data from premarketing clinical efficacy and safety trials, a briefing document from the US Food and Drug Administration Psychopharmacological Drugs Advisory Committee, published studies, and abstracts presented at national and international meetings. International Pharmaceutical Abstracts and MEDLINE were searched for relevant citations, with no limitation on year.

RESULTS

Ziprasidone has been reported to be an effective antipsychotic drug for both positive and negative symptoms of schizophrenia, and long-term use has been effective in preventing relapse. Its 5-hydroxytryptamine (HT)1D-antagonist and 5-HT(1A)-agonist activity are consistent with a potential for antidepressant and anxiolytic activity beyond its antipsychotic effects. Ziprasidone has been associated with a low incidence of sedative effects, a low likelihood of extrapyramidal symptoms and postural hypotension, and no anticholinergic effect, although it may cause transient hyperprolactinemia. Unlike most atypical antipsychotic drugs, ziprasidone is not associated with weight gain, hyperlipidemia, or elevated plasma glucose levels. It is, however, more likely than other atypical antipsychotic drugs to increase the QTc interval (QT interval corrected for heart rate). For acute psychotic symptoms in patients with schizophrenia, schizoaffective disorder, or acute mania, ziprasidone is administered twice daily at a usual daily dose of 80 to 160 mg, whereas 40 mg/d may be an effective maintenance dose.

CONCLUSIONS

Differences in efficacy and tolerability between existing atypical antipsychotic drugs allow individualization of drug therapy for patients with schizophrenia or schizoaffective disorder. Ziprasidone differs from other atypical antipsychotic drugs in several clinically important ways, although further experience is necessary to clarify the significance of these differences.

Effects of intravenous lidocaine overdose on cardiac electrical activity and blood pressure in the horse

This study aimed to identify blood serum lidocaine concentrations in the horse which resulted in clinical signs of intoxication, and to document the effects of toxic levels on the cardiovascular and cardiopulmonary systems. Nineteen clinically normal mature horses of mixed breed, age and sex were observed. Lidocaine administration was initiated in each subject with an i.v. loading dose of 1.5 mg/kg bwt and followed by continuous infusion of 0.3 mg/kg bwt/min until clinical signs of intoxication were observed. Intoxication was defined as the development of skeletal muscle tremors. Prior to administration of lidocaine, blood samples for lidocaine analysis, heart rate, mean arterial blood pressure, systolic blood pressure, diastolic blood pressure, respiratory rate and electrocardiographic (ECG) data were collected. After recording baseline data, repeat data were collected at 5 min intervals until signs of intoxication were observed. The range of serum lidocaine concentrations at which the clinical signs of intoxication were observed was 1.85-4.53 microg/ml (mean +/- s.d. 3.24 +/- 0.74 microg/ml). Statistically significant changes in P wave duration, P-R interval, R-R interval and Q-T interval were observed in comparison to control values, as a result of lidocaine administration. These changes in ECG values did not fall outside published normal values and were not clinically significant. Heart rate, blood pressures and respiratory rates were unchanged from control values. This study establishes toxic serum lidocaine levels in the horse, and demonstrates that there were no clinically significant cardiovascular effects with serum lidocaine concentrations less than those required to produce signs of toxicity.