Deliberate Self-Poisoning with Plants in Southeastern France, a Poison Center 20-Year Report.

INTRODUCTION: In a few regions of the globe, deliberate botanical intoxication may induce significant rates of toxicity and fatality. The objective of this report was to describe plant self-intoxication using the experiences of the southeastern France poison control center (PCC) between 2002 and 2021. RESULTS: During those 20 years, 262 deliberate plants poisonings were reported involving 35 various plants. In most of the cases, poisoning was caused by Nerium oleander (n = 186, 71%), followed by the Datura genus (4.2%), Ricinus communis (3.8%), Taxus baccata (1.9%), Digitalis purpurea (1.2%), Aconitum nape (1.9%), Myristica fragans (1.5%), and Pyracantha coccine (1.2%). Through the 262 plants poisonings, 19 patients among the 186 Nerium oleander poisonings received Digifab as an antidote and 1 patient received physostigmine among the 11 Datura poisonings. Only four deaths were reported for this review, each involving Nerium oleander. DISCUSSION: The first involved species was Nerium oleander (71% of all plants poisonings), then Datura sp and Ricinus communis. It is explained by this native local species' important repartition. Most patients must be admitted to an emergency department for adapted medical care; however, only 41 of them described severe poisonings symptoms. Even fewer needed an antidote, only 20 patients. There is no protocol for the use of a specific treatment, and it might be interesting to develop one for this purpose. MATERIAL AND METHODS: This retrospective review was realized with files managed by the southeastern France PCC based in Marseille from 2002 to 2021. Our department covers the complete French Mediterranean coast, Corsica, and tropical islands (Reunion Island, Mayotte). For every patient, toxicity was evaluated using the Poison Severity Score (PSS).

Unintentional poisoning from decanted toxic household chemicals.

BACKGROUND: Although poisonings due to a toxic substance being decanted into a secondary container are often reported to poison centers, we were unable to locate prior European data about their circumstances, incidence and consequences. We sought to describe the circumstances and outcomes of this behavior. MATERIALS AND METHOD: We conducted a prospective study of all poison exposures involving transfer to a secondary container reported to our poison center during a six month interval (January 1, 2021 through June 30, 2021). We called patients and clinicians for follow up the next day. We used a prepared questionnaire and added the responses to the national database for French poison centers. RESULTS: We identified and included 238 patients (104 male, 134 female) with a median age of 39 years [range 0-94 y]. Exposure was mainly oral (n = 221), the secondary container was mainly a water bottle (n = 173), toxic substances were essentially cleaning products (n = 63) or bleach (n = 48). Symptoms were gastrointestinal (vomiting, diarrhea, abdominal pain) (n = 143) or respiratory (cough, dyspnea, aspiration pneumonia) (n = 15). The World Health Organisation/International Programme on Chemical Safety/European Commission/European Association of Poison Centres and Clinical Toxicologists Poisoning Severity Score was none in 76 cases (31.9%), minor in 147 (61.8%), moderate in 12 (5%), and severe in three cases (1.3%). Products that led to severe poisoning contained either ammonium hydroxide or sodium hydroxide. Two of the patients required intensive care treatment. At the end of the follow-up, 235 patients fully recovered, and three patients had sequelae. CONCLUSIONS: The study illustrates the risk of toxic substance transfer. Water bottles were the secondary containers in most exposures to decanted substances. Most had minor or no effects, but nearly one-quarter were admitted to the hospital. The few severe exposures involved either ammonium hydroxide or sodium hydroxide.

Buprenorphine exposures in adolescents and adults: a 10-year experience of a French Poison Control Center.

Buprenorphine has been used in pain and opioid addiction management for nearly 25 years. Compared to methadone, buprenorphine is thought to exhibit less side effects and respiratory depression in case of accidental or suicidal overdose. The aim was to describe the characteristics of exposures reported to a French Poison Control Center (PCC). We conducted a retrospective study including all buprenorphine exposures for which advice of our PCC was required between 2009 and 2018. After data extraction from the electronic medical files and anonymous transfer to an Access base, a statistical descriptive analysis was performed focusing on adolescents over 10 years old and adults. One hundred and ninety-nine cases were analyzed. The major circumstances of exposure were suicide attempts and overdoses in patients with previously identified substance abuse. Buprenorphine exposures have been reduced by 50% between 2009 and 2018. Coingestions, often with benzodiazepines or antidepressants, were almost systematic and 79% of all the series exhibited at least one symptom. Among the symptomatic cases, neurological effects were the most frequent (83%) and respiratory symptoms occurred in 13%. No deaths were registered. Severity did not exceed PSS1 in 80% of all the cases. Treatment was mainly symptomatic even though naloxone was required in at least 5% of the symptomatic cases. Within 24 h after exposure, 120 patients were discharged from the emergency department. Despite loss to follow-up, our results suggest that buprenorphine is relatively safe.

Buprenorphine poisoning in children: a 10-year-experience of Marseille Poison Center.

Buprenorphine is a µ-partial agonist and k-antagonist acting on central opioid receptors. Patented for analgesia in 1968, buprenorphine has been used as opioid substitutive therapy since the 1990s, as well as methadone. The aim was to document pediatric poisoning, to discover the severity, and to evaluate the treatment with naloxone. All pediatric poisonings reported to the poison control center Marseille (France)-from January 1, 2009 to December 31, 2018-were included. Analysis put value on gender, age, estimated quantity, symptoms and their delay, place of treatment, medical treatment, utilization of antidotes, severity of intoxications, and patients' outcome. Fifty-four infant poisonings with buprenorphine were recorded, doses varied between 1 and 36 mg, and children showed mainly neurological (somnolence, miosis…) and gastroenteric (vomiting) effects. Pulmonary effects were described for four children. According to the poisoning severity score, 8 intoxications were classified as 'no symptoms or signs', 37 as minor poisonings, 3 as moderate, none as severe or fatal and 6 were unknown. Medical care was required for 46 children, and four of them were treated with naloxone. Buprenorphine poisoning can cause neurological, gastroenteric, and respiratory symptoms. Even licking a tablet leads to intoxication because of maximal tablet's absorption while placing it under the tongue. Hospital admission is necessary even at small doses. Naloxone was efficient in the four described cases. Parents have to be aware of the poisoning risk with buprenorphine. Recently, commercialized instantly dissolving formulations could cause more severe intoxications.

Regulation of Neuroinflammation: What Role for the Tumor Necrosis Factor-Like Weak Inducer of Apoptosis/Fn14 Pathway?

Observed in many central nervous system diseases, neuroinflammation (NI) proceeds from peripheral immune cell infiltration into the parenchyma, from cytokine secretion and from oxidative stress. Astrocytes and microglia also get activated and proliferate. NI manifestations and consequences depend on its context and on the acute or chronic aspect of the disease. The tumor necrosis factor-like weak inducer of apoptosis (TWEAK)/Fn14 pathway has been involved in chronic human inflammatory pathologies such as neurodegenerative, autoimmune, or malignant diseases. New data now describe its regulatory effects in tissues or fluids from patients with neurological diseases. In this mini-review, we aim to highlight the role of TWEAK/Fn14 in modulating NI in multiple sclerosis, neuropsychiatric systemic lupus erythematosus, stroke, or glioma. TWEAK/Fn14 can modulate NI by activating canonical and non-canonical nuclear factor-κB pathways but also by stimulating mitogen-activated protein kinase signaling. These downstream activations are associated with (i) inflammatory cytokine, chemokine and adhesion molecule expression or release, involved in NI propagation, (ii) matrix-metalloproteinase 9 secretion, implicated in blood-brain barrier disruption and tissue remodeling, (iii) astrogliosis and microgliosis, and (iv) migration of tumor cells in glioma. In addition, we report several animal and human studies pointing to TWEAK as an attractive therapeutic target.

Pediatric Patients With Solid or Hematological Tumor Disease: Vancomycin Population Pharmacokinetics and Dosage Optimization.

BACKGROUND: In pediatric cancer patients, determination of optimal vancomycin dosage is essential because of high risk of inadequate concentrations and bacterial resistance. The aim of this study was to determine vancomycin pharmacokinetic parameters in this population and propose dosage optimization to achieve optimal concentration. METHODS: We retrospectively reviewed the use of vancomycin in pediatric cancer patients with febrile neutropenia (hematological or solid tumor disease). Vancomycin was administered by continuous infusion, and dosages were adapted according to therapeutic drug monitoring results. Blood cultures were performed before the first dose of antibiotic. Vancomycin pharmacokinetic population parameters were determined using NONMEM software, and dosage simulations were performed according to the target concentration (20-25 mg/L). RESULTS: One hundred twenty-one patients were included in this study, representing 301 vancomycin concentrations. Blood cultures were positive in 37.5% of patients, and observed pathogens were mainly Staphylococcus spp. (43.8% methicillin resistant). Volume of distribution (95% confidence interval) was 34.7 L (17.3-48.0), and total apparent clearance (CL) (95% confidence interval) was correlated to body weight, tumor disease, and cyclosporine coadministration: CL = θCL × (WT/70) L/h with θCL = 3.49 (3.02-3.96), 4.66 (3.98-5.31), and 4.97 (4.42-5.41) in patients managed for hematological malignancies with or without cyclosporine coadministration and for solid malignancies, respectively. Based on simulation results, vancomycin dosage (milligram per kilogram) should be adapted to each child on the basis of its body weight and cyclosporine coadministration. CONCLUSIONS: Our results highlight the requirement to adapt vancomycin dosage in cancer pediatric population. Simulations have allowed to describe new dosage schedules, and a chart was created for clinicians to adapt vancomycin dosage.

Nicotine and metabolites determination in human plasma by ultra performance liquid chromatography-tandem mass spectrometry: a simple approach for solving contamination problem and clinical application.

A quantitative method using ultra performance liquid chromatography-tandem mass spectrometry is described for simultaneous determination of nicotine and its metabolites (cotinine and trans-3'- hydroxycotinine) in human plasma. Aliquots of 0.25 mL of plasma specimens were used for analysis, and 3 analytes were extracted by liquid-liquid extraction. The main problem was blank plasma contamination with environmental nicotine. Activated charcoal was used to avoid this analytical interference. For optimized chromatographic performance, a basic mobile phase consisting of 0.2% ammonia in water (mobile phase A, pH10.6) and acetonitrile (mobile phase B) was selected. The analytes were separated on a 50 mm × 2.1 mm BEH C18 column, 1.7 µm particle size, and quantified by MS/MS using multiple-reaction monitoring (MRM) in positive mode. The chromatographic separation was achieved in 3 min followed by 1.2 min of column equilibration. The calibration curves were linear in the concentration range of 10-1000 ng/mL with correlation coefficients exceeding 0.99. Within-day precisions and between-day precisions (CV, %) were <15 %. The accuracy expressed as bias was within ±15% for all analytes. The recovery values ranged from 50% to 97%. The ions used for quantification of nicotine, cotinine and 3-OH-cotinine were 166.9 > 129.7; 176.9 > 79.7; 192.9 > 79.7 m/z, respectively. The original blank sample preparation solved the problem of contamination in a cost-effective and efficient way. The validated method has been routinely used for analysis of nicotine and metabolites and determination of hydroxycotinine/cotinine metabolic ratio. This biomarker seems to be interesting at predicting response of nicotine patch replacement therapies.

Population pharmacokinetics of ertapenem in juvenile and old rats.

Ertapenem is a parenteral broad-spectrum carbapenem active against Gram-negative pathogens, which has been approved for treatment of different infectious situations in adults and children. Favourable pharmacokinetics and pharmacodynamics have been established in young adults. In the elderly, dosing regimen adaptations are not recommended. Nevertheless, pharmacokinetic studies in paediatrics have not been published yet. The aim of this study was to document whether age influenced ertapenem disposition by comparing its pharmacokinetics in three groups of rats. Rats were separated into three groups: very young rats 21-day-old, 10-week-old and 7-month-old rats. A population pharmacokinetic model was built and evaluated, using the NONMEM software. Pharmacokinetic parameters, interindividual variability and residual variability were estimated. The final model was evaluated by a bootstrap procedure and visual predictive check. The ertapenem concentration-time data were best described by a one-compartment model with zero-order input and first-order elimination. Effect of very young and old ages was estimated on central volume and clearance. Model evaluation indicated that the model was robust and parameter estimates were accurate. Central volume was found to be dependent on age and increase with age. Although the dosing regimen was weight adjusted, clearance was found to depend not only on age but also on weight. This study clearly documents changes in ertapenem pharmacokinetics according to group of age. These results suggest that paediatric dosing regimen cannot be directly extrapolated from a pharmacokinetic model in young adults unless it took into account age-induced modifications.

Pharmacokinetics and absolute bioavailability of phenobarbital in neonates and young infants, a population pharmacokinetic modelling approach.

Phenobarbital is widely used for treatment of neonatal seizures. Its optimal use in neonates and young infants requires information regarding pharmacokinetics. The objective of this study is to characterize the absolute bioavailability of phenobarbital in neonates and young infants, a pharmacokinetic parameter which has not yet been investigated. Routine clinical pharmacokinetic data were retrospectively collected from 48 neonates and infants (weight: 0.7-10 kg; patient's postnatal age: 0-206 days; GA: 27-42 weeks) treated with phenobarbital, who were administered as intravenous or suspension by oral routes and hospitalized in a paediatric intensive care unit. Total mean dose of 4.6 mg/kg (3.1-10.6 mg/kg) per day was administered by 30-min infusion or by oral route. Pharmacokinetic analysis was performed using a nonlinear mixed-effect population model software). Data were modelled with an allometric pharmacokinetic model, using three-fourths scaling exponent for clearance (CL). The population typical mean [per cent relative standard error (%RSE)] values for CL, apparent volume of distribution (Vd ) and bioavailability (F) were 0.0054 L/H/kg (7%), 0.64 L/kg (15%) and 48.9% (22%), respectively. The interindividual variability of CL, Vd , F (%RSE) and residual variability (%RSE) was 17% (31%), 50% (27%), 39% (27%) and 7.2 mg/L (29%), respectively. The absolute bioavailability of phenobarbital in neonates and infants was estimated. The dose should be increased when switching from intravenous to oral administration.

Interaction of thiopental with esomeprazole in critically ill patients.

INTRODUCTION: Thiopental is a thiobarbiturate given in the case of brain injuries to reduce intracranial pressure and to manage cerebral ischemia. A pharmacokinetic model has been described previously in critically ill patients with a different therapeutic strategy. New treatment options prompted us to investigate if drug-drug interactions occur. A new model is proposed describing the influence of concomitant administration of esomeprazole on the distribution of thiopental. METHOD: The study population comprised 52 critically ill patients (body weight 47.1-114 kg) aged 18-78 years who had been admitted into the critical care unit for treatment of intracranial hypertension. A total mean dose of 282.8 ± 172.7 mg/kg was given in 96 ± 72 h. Pharmacokinetic analysis was performed by using a nonlinear mixed-effect population model. RESULT: A one-compartment open model with first-order elimination identified two covariates, namely, body weight on clearance and volume of distribution, and the administration of esomeprazole on volume of distribution. The mean values (% relative standard error) for total clearance (CL) and for central volume of distribution (Vd) in patients with and without concomitant esomeprazole were 5.3 L/h (9.2 %) and 256.1 (6.4 %) and 153.2 l (19.2 %), respectively. CONCLUSION: Based on these results, we conclude that concomitant administration of esomeprazole increases the volume of distribution and the half-live of thiopental. This drug-drug interaction should be considered when a target concentration has to be reached.

Population pharmacokinetic analysis during the first 2 years of life: an overview.

Three decades after its introduction, pharmacokinetic population approaches have become a reference method for drug modelling, particularly in paediatrics. The main practical limitation in this specific population is the collected blood volume. Pharmacokinetic population approaches using sparse sampling may resolve this issue. The pharmacokinetics of many drugs have been studied during the last 25 years using such methods. This review summarizes all of the published studies concerning population pharmacokinetic approaches in paediatric subjects from neonate to 2 years old. A literature search was conducted using the PubMed database, from 1985 to December 2010, using the following terms: pharmacokinetic(s), population, paediatric/pediatric and neonate(s). Articles were excluded if they were not pertinent according to our criteria. References of all relevant articles were also evaluated. Ninety-eight studies were included in this review. The following information was extracted from the articles: drug name, therapeutic class, population size, age of patients, number of samples per patient, covariates used for clearance and volume of distribution estimates, software used for modelling and validation methods. An increasing rate of publications over the years was observed; 44 different drugs were studied using a pharmacokinetic population approach. Antibacterials were the most studied class of drugs, including a large number of studies devoted to vancomycin and gentamicin. It must be underlined that few studies have been performed on anticonvulsant drugs and anaesthetics used in clinical daily practice conditions.

Vancomycin: a review of population pharmacokinetic analyses.

Despite nearly five decades of clinical use, vancomycin has retained a significant and uncontested niche in the antibacterial arsenal because of its consistent activity against almost all Gram-positive bacteria. Nevertheless, major vancomycin toxicities have been reported in the literature - in particular, nephrotoxicity and ototoxicity. Vancomycin pharmacokinetics have been described in numerous studies for 25 years. This review presents a synthesis of the reported population pharmacokinetic models of vancomycin. The objective was to determine if there was a consensus on a structural model and which covariates were identified. A literature search was conducted from the PubMed database, from its inception through December 2010, using the following terms: 'vancomycin', 'pharmacokinetic(s)', 'population', 'model(ling)' and 'nonlinear mixed effect'. Articles were excluded if they were not pertinent. The reference lists of all selected articles were also evaluated. Twenty-five articles were included in this review: 15 models concerned paediatric patients and ten models were conducted in adults. In neonates and infants, the pharmacokinetics of vancomycin were mainly described by a one-compartment model, whereas in adults, a two-compartment model was preferentially used. Various covariates were tested but only three (age, creatinine clearance [CL(CR)] and body weight) were included in almost all of the described models. After inclusion of these covariates, the mean (range) values of the interindividual variability in the clearance and volume of distribution were 30% (15.6-45%) and 23% (12.6-48%), respectively. The mean (range) value of the residual variability was 20% (7-39.6%). This review highlights the numerous population pharmacokinetic models of vancomycin developed in recent decades and concludes with relevant information for clinicians and researchers. To optimize vancomycin dosage, this review points out the relevant covariates according to the target population. In adults, dosage optimization depends on CL(CR) and body weight, while in children, it depends on age, body weight and CL(CR). For future population pharmacokinetic studies, a sensitive liquid chromatography-tandem mass spectrometry method could be used and new covariates such as cardiac output or possible renal transporters could be tested. Finally, we suggest that external evaluation should be the first step in a pharmacokinetic analysis of vancomycin rather than describing a new model.

Vancomycin: Predictive Performance of a Population Pharmacokinetic Model and Optimal Dose in Neonates and Young Infants.

INTRODUCTION: Model evaluation is an important issue in population pharmacokinetic analyses. The objectives were to evaluate the predictive performance of previously published pediatric population pharmacokinetic models for vancomycin in a new data set and to propose an optimal dose to obtain a vancomycin concentration target. METHODS: External evaluation was conducted for all the published models of vancomycin in neonates and young infants with a new data set of 70 patients. Bias and accuracy were calculated. Advanced analyses were performed to evaluate the predictive performance of the best model. This population pharmacokinetic analysis was performed to simulate doses of vancomycin according to the appropriate target concentration. RESULTS: All models gave almost the same results, except 2 that were not acceptable. Nevertheless, the model described by Oudin et al presented the best results with a bias and accuracy of 4.0% and 27.8%, respectively. Simulations showed that the maintenance dose should be adjusted more precisely to each neonate based on his or her weight and serum creatinine value. CONCLUSION: Simulations have allowed the authors to describe new dosage schedules, and a chart was created to help clinicians to adapt dosage of vancomycin. Because of pharmacokinetic variability, vancomycin still requires therapeutic drug monitoring.

[Level of evidence for therapeutic drug monitoring of aminoglycosides]. / Niveau de preuve du suivi thérapeutique pharmacologique des aminosides.

Aminoglycosides are major antibiotics indicated for the treatment of infection with gram-negative bacilli. They are characterized by high clinical effectiveness but their main drawback is the occurrence of toxicity in a significant number of patients. Pharmacokinetic parameters of aminoglycosides exhibit wide inter-individual variability and the relationships between concentration and effect have been clearly demonstrated. Consistent studies have demonstrated that therapeutic drug monitoring (TDM) of aminoglycosides administered in multiple daily doses was cost-effective in maximising antibiotic efficacy and/or reducing incidence of toxicity. Therefore TDM of aminoglycosides should be considered "essential". Level of evidence for TDM of aminoglycosides administered once daily is not so clearly demonstrated however it should be highly recommended.

[Level of evidence for therapeutic drug monitoring of teicoplatin]. / Niveau de preuve du suivi thérapeutique pharmacologique de la teicoplanine.

Teicoplanin is a glycopeptid antibiotic used for treatment of serious infections caused by Gram+ bacteriae. The treatment scheme corresponds to an initial loading dose followed by maintenance dose. High interindividual pharmacokinetic variability and strong relation between high through concentrations, dose and clinical success, support the need of therapeutic drug monitoring using through concentrations. Achieving through concentrations ≥ 10-15 mg/L or ≥ 20-40 mg/L, regarding the measurement method and the infection severity, is recommended to increase clinical success rate. The level of proof of therapeutic drug monitoring is evaluated: "necessary".

[Not Available]. / Niveau de preuve du suivi thérapeutique pharmacologique des aminosides.

Aminoglycosides are major antibiotics indicated for the treatment of infection with gram-negative bacilli. They are characterized by high clinical effectiveness but their main drawback is the occurrence of toxicity in a significant number of patients. Pharmacokinetic parameters of aminoglycosides exhibit wide inter-individual variability and the relationships between concentration and effect have been clearly demonstrated. Consistent studies have demonstrated that therapeutic drug monitoring (TDM) of aminoglycosides administered in multiple daily doses was cost-effective in maximising antibiotic efficacy and/or reducing incidence of toxicity. Therefore TDM of aminoglycosides should be considered "essential". Level of evidence for TDM of aminoglycosides administered once daily is not so clearly demonstrated however it should be highly recommended.

[Not Available]. / Niveau de preuve du suivi thérapeutique pharmacologique de la teicoplanine.

Teicoplanin is a glycopeptid antibiotic used for treatment of serious infections caused by Gram+ bacteriae. The treatment scheme corresponds to an initial loading dose followed by maintenance dose. High interindividual pharmacokinetic variability and strong relation between high through concentrations, dose and clinical success, support the need of therapeutic drug monitoring using through concentrations. Achieving through concentrations ≥10-15 mg/L or ≥20-40 mg/L, regarding the measurement method and the infection severity, is recommended to increase clinical success rate. The level of proof of therapeutic drug monitoring is evaluated: "necessary".

Effects of L-Dopa on circadian rhythms of 6-OHDA striatal lesioned rats: a radiotelemetric study.

Temporal variation in the motor function of Parkinson's disease (PD) patients suggests the potential importance of a chronobiological and chronopharmacological approach in its clinical management. We previously documented the effects of striatal injection of 6-OHDA (as an animal model of PD) on the circadian rhythms of temperature (T), heart rate (HR), and locomotor activity (A). The present work assessed the possible influence of L-Dopa on these same rhythms in the 6-OHDA animal model of PD. The study began after a four-week recovery period following surgical implantation of telemetric devices to monitor the study variables and/or anaesthesia. The study was divided into an initial one-week control period (W1) for baseline measurement of T, HR, and A rhythms. Thereafter, stereotaxic 6-OHDA lesioning was done. and a second monitoring for two weeks followed (W2, W3). Rats were then randomly divided into two groups: eight control rats received, via a mini-osmotic pump implanted subcutaneously, the excipient saline; the other eight rats received L-Dopa (100 mg/kg SC/day). After a seven-day period (W4), the pumps were removed and the T, HR, and A rhythms were monitored for two weeks (W5 and W6). To control for 6-OHDA striatal dopamine-induced depletion, 12 other rats were injected by identical methods (eight rats with 6-OHDA and four controls with saline) and sacrificed at W1, W3, and W5 for dopamine striatal content determination. To verify the delivery of levodopa from the osmotic pumps, plasma levels of levodopa and its main metabolites 3-OMD, DOPAC, and HVA were determined on separate group of rats receiving the drug under the same experimental conditions (osmotic pumps delivering continuously 10 microl/h for seven days, 100 mg/kg/subcutaneously). Our results agree with previously reported rhythmic changes induced by 6-OHDA--loss of circadian rhythmicity or changes in the main parameters of the registered rhythms. When circadian rhythmicity was abolished, L-Dopa treatment improved or accelerated recovery of the circadian rhythms, the effect being more pronounced for the HR rhythm. When circadian rhythms were not abolished but perturbed, L-Dopa treatment did not improve the 6-OHDA-induced changes in the T and A mesor (24 h mean level), while a significant effect was observed for HR. It appears that constant-rate L-Dopa infusion is unable to totally balance dopamine depletion; taking into account the circadian pattern of many structures implicated in drug effect, a sinusoidal delivery of L-Dopa must be evaluated in future experiments.

Effects of induced hyperthermia on pharmacokinetics of ropivacaine in rats.

Ropivacaine is a local anaesthetic used for epidural anaesthesia and postoperative pain relief. Hyperthermia is a very common sign of infection associated with variations in physiological parameters, which may influence drugs pharmacokinetics. The aim of this study was to determine the effects of induced hyperthermia on ropivacaine pharmacokinetics in rats. Two groups of six rats were given a single subcutaneous ropivacaine injection. Hyperthermia-induced animals were placed in a water bath to obtain a stable mean core temperature of 39.7 degrees C. After blood samples collection, ropivacaine serum concentrations and pharmacokinetic parameters were determined. Two other groups of six rats were sacrificed 30 min after ropivacaine injection to determine serum and tissues (brain and heart) concentrations. Our results (median +/- inter quartile range) reveal a significant increase of the total apparent clearance (0.0151 +/- 0.000800 L/min vs. 0.0134 +/- 0.00134 L/min), apparent volume of distribution (V(d)) (2.19 +/- 0.27 L vs. 1.57 +/- 0.73 L) and a significant decrease in exposure (488 +/- 50.6 mgxmin/L vs. 572 +/- 110 mgxmin/L) in induced-hyperthermia group. We observed a significant increase in brain ropivacaine concentration in hyperthermic rats (8.39 +/- 8.42 microg/g vs. 3.48 +/- 3.26 microg/g) and no significant difference between cardiac concentrations in the two groups (5.38 +/- 4.83 microg/g vs. 3.73 +/- 2.44 microg/g). Results suggest a higher tissular distribution of ropivacaine and an increase in blood-brain barrier permeability during hyperthermia. The hyperthermia-induced increase in V(d) could be responsible for an increase in cerebral ropivacaine toxicity. These experimental data provide a basis for future clinical investigations in relation to local anaesthetic use in hyperthermic patients.