Incidence, causes and prognosis of hypotension related to meprobamate poisoning

Plasma vs heart tissue concentration in humans - literature data analysis of drugs distribution

Little is known about the uptake of drugs into the human heart, although it is of great importance nowadays, when science desires to predict tissue level behavior rather than to measure it. Although the drug concentration in cardiac tissue seems a better predictor for physiological and electrophysiological changes than its level in plasma, knowledge of this value is very limited. Tissue to plasma partition coefficients (Kp) come to rescue since they characterize the distribution of a drug among tissues as being one of the input parameters in physiologically based pharmacokinetic (PBPK) models. The article reviews cardiac surgery and forensic medical studies to provide a reference for drug concentrations in human cardiac tissue. Firstly, the focus is on whether a drug penetrates into heart tissue at a therapeutic level; the provided values refer to antibiotics, antifungals and anticancer drugs. Drugs that directly affect cardiomyocyte electrophysiology are another group of interest. Measured levels of amiodarone, digoxin, perhexiline and verapamil in different sites in human cardiac tissue where the compounds might meet ion channels, gives an insight into how these more lipophilic drugs penetrate the heart. Much data are derived from postmortem studies and they provide insight to the cardiac distribution of more than 200 drugs. The analysis depicts potential problems in defining the active concentration location, what may indirectly suggest multiple mechanisms involved in the drug distribution within the heart. Copyright © 2015 John Wiley & Sons, Ltd.

Doppler echocardiography in shocked patients

PURPOSE OF REVIEW

To reiterate the necessity of integrating echocardiography in the management of shocked patients and to propose a step-by-step functional evaluation of hemodynamics proven to optimize hemodynamic monitoring and to adapt the treatment.

RECENT FINDINGS

Echocardiography has become the cornerstone to hemodynamic monitoring. By providing real-time images, echocardiography has the advantage over 'blind' technologies of an excellent diagnostic performance and of quick provision of information about the pathophysiology of circulatory failure. Critical care echocardiography (CCE) has been defined as echocardiography performed and interpreted by intensivists themselves, 7/7 and 24/24, at the bedside. Basic CCE is mainly a diagnostic approach, allowing quick and focused examination of cardiac function. Advanced CCE is the core of functional hemodynamic monitoring. It is based not only on transthoracic echocardiography but also strongly on transesophageal echocardiography, a very useful approach in ventilated patients. However, this monitoring is discontinuous. A single-use 72-h indwelling transesophageal probe was recently tested, allowing functional hemodynamic monitoring more continuously.

SUMMARY

Echocardiography has become a hemodynamic monitoring technique used worldwide. It allows to make a quick and simple diagnosis of typical hemodynamic situations, by means of basic CCE, and also to achieve real functional hemodynamic monitoring, through advanced CCE.

Deliberate drug poisoning with slight symptoms on admission: are there predictive factors for intensive care unit referral? A three-year retrospective study

Deliberate drug poisoning leads to 1% of emergency department (ED) admissions. Even if most patients do not exhibit any significant complication, 5% need to be referred to an intensive care unit (ICU). Emergency physicians should distinguish between low- and high-acuity poisoned patients at an early stage to avoid excess morbidity. Our aim was to identify ICU transfer factors in deliberately self-poisoned patients without life-threatening symptoms on admission. We performed a 3-year retrospective observational study in a university hospital. Patients over 18 years of age with a diagnosis of deliberate drug poisoning were included. Clinical and toxicological data were analysed with univariate tests between groups (ED stay versus ICU transfer). Factors associated with ICU admission were then included in a logistic regression analysis. Two thousand five hundred and sixty-five patients were included. 63.2% were women, and median age was 40 (28-49). 142 patients (5.5%) were transferred to ICU. Cardiac drugs [adjusted OR (aOR) = 19.81; 95% confidence interval (95% CI): 7.93-49.50], neuroleptics (aOR = 2.78; 95% CI: 1.55-4.97) and meprobamate (aOR = 2.71; 95% CI: 1.27-5.81) ingestions were significantly linked to ICU admission. A presumed toxic dose ingestion (aOR = 2.27; 95% CI: 1.28-4.02), number of ingested tablets (aOR = 1.01; 95% CI: 1.01-1.02 for each tablet) and delay between ingestion and ED arrival <2 hr (aOR = 2.85; 95%CI: 1.62-5.03) were also factors for ICU referral. The Glasgow Coma Scale was the only clinical feature associated with ICU admission (aOR = 1.57; 95% CI: 1.44-1.70 for each point loss). These results suggest that emergency physicians should pay particular attention to toxicological data on ED admission to distinguish between low- and high-acuity self-poisoned patients.

Pharmacokinetics of meprobamate in overdose treated with continuous venovenous hemodiafiltration (CVVHDF)

We report a case of massive suicidal overdose of meprobamate leading to cardiovascular collapse, respiratory failure, and severe central nervous system depression. We observed first-order elimination kinetics despite significant overdose, and demonstrated effectiveness of continuous venovenous hemodiafiltration (CVVHDF) for extracorporeal removal of meprobamate in this patient. Total body clearance was calculated to be 87 mL/minute, with 64 mL/minute (74%) due to CVVHDF. CVVHDF was stopped after 36 hours, and the patient made an uneventful recovery.

[Severe meprobamate poisoning: description of 146 cases in a French department]

Meprobamate poisoning are serious and sometimes fatal. Faced with a potential stop of marketing, we conducted a multicenter retrospective study to assess the severity criteria presented by patients admitted to the ICU for severe meprobamate poisoning, whether with alone form or in combination with aceprometazine. One hundred fourty-six patients have been enrolled between January 2005 and June 2011: 38 had a single meprobamate poisoning, 104 to meprobamate and aceprometazine and 4 to both forms. At admission, 88% of patients exhibited coma (Glasgow ≤ 7) and half of them a systolic blood pressure ≤ 90 mmHg. Mortality rate was 3%. Our results did not find any significant between-group difference, either in regard of clinical or biological severity criteria. These data argue for a cessation of marketing of all meprobamate-based specialities.

Acute hand ischemia after intra-arterial injection of meprobamate powder

BACKGROUND

Meprobamate tablets contain microcrystalline cellulose, a potent embolic agent that has been shown to cause gangrene in animal studies. Microvascular embolization caused by microcrystalline cellulose can contribute to the ischemic process.

OBJECTIVE

We report a case of acute hand ischemia after accidental intra-arterial injection of crushed meprobamate powder in a 23-year-old male drug abuser.

CASE REPORT

The distal tips of the patient's right thumb, index finger, ring finger, and little finger continued to develop gangrene despite medical therapy with heparinization, low molecular-weight dextran infusion, corticosteroid administration, and hyperbaric oxygen therapy.

CONCLUSION

We believe this is the first case of acute limb ischemia caused by intra-arterial injection of meprobamate powder documented in humans. Emergency physicians should be aware that accidental intra-arterial injection of crushed oral drug formulations is potentially limb threatening and prompt recognition of similar clinical scenarios is of vital importance.

Evaluation of the first immunoassay for the semi-quantitative measurement of meprobamate in human whole blood or plasma using biochip array technology

BACKGROUND

Meprobamate is a carbamate, and the main metabolite of carisoprodol. It is used as an anxiolytic agent. Overdose of both drugs produces intoxication that is often serious and sometimes life threatening. However there was until now no immunoassay for the diagnosis of this intoxication.

METHODS

A chemiluminescent immunoassay for the semi-quantitative measurement of meprobamate in human blood and plasma has recently been developed, using the Evidence Investigator system (Randox®). In this study, the immunoassay was evaluated by testing drug-free (n=10) or spiked whole blood and plasma samples (n=70), and authentic post mortem whole blood samples from deceased patients in which meprobamate was present (n=38) or not (n=10). A previously validated gas chromatography-mass spectrometry (GC-MS) method was used for confirmation and quantification. 97 psychoactive drugs including carisoprodol were analyzed for possible interference.

RESULTS

With a cut-off at 0.5 mg/L, specificity, sensitivity and accuracy were 100%, 97.2% and 97.6%, respectively. All the untreated patients presented results under the cut-off. Meprobamate was not detected in three whole blood samples spiked with concentrations under the therapeutic range. In the authentic patients (n=48), there were no false-negative results. A good correlation was found between the immunoassay and GC-MS (r=0.90). Quantitative results of the immunoassay are approximately two-fold lower than GC-MS results. Only carisoprodol presented a cross-reactivity, 38±6.6% at 10 mg/L, and 26±4.8% at 100mg/L.

CONCLUSION

The first meprobamate immunoassay has shown very good specificity, selectivity and accuracy, which allow its use in hospital clinical laboratories for rapid diagnosis of meprobamate (or carisoprodol) intoxications.