Death of an apprentice bodybuilder following 2,4-dinitrophenol and clenbuterol intake.

We present the case of a 17-year-old man, who died after 2,4-dinitrophenol (DNP) and clenbuterol consumption, which he likely took for physical enhancement. Forensic post-mortem examination revealed a yellowish skin colour and nonspecific signs of asphyxia. Analytical confirmation of the intoxication was obtained in blood and urine, with high levels of DNP and clenbuterol. Both of these substances are used by bodybuilders as DNP enhance lipolysis and clenbuterol has anabolic properties, but their toxicity is underestimated. DNP uncouples oxidative phosphorylation, leading to thermogenesis and even relatively small doses can cause fatal hyperthermia. Clenbuterol is a ß2 agonist that causes electrolyte disturbances (hypokalemia and hyperglycemia mostly) and death have been described through coronary vasospasm. Given the circumstances in which the body was found and toxicological results, we believe the cause of death to be fatal hyperthermia from DNP intake. These substances are illegal in many countries, but easily bought online. Through this availability, the last decades have seen an increase of fatal intoxications. Websites selling them are regularly closed by French public authorities and Interpol, but unfortunately it seems insufficient.

Feasibility of, and critical paths for mycophenolate mofetil Bayesian dose adjustment: pharmacological re-appraisal of a concentration-controlled versus fixed-dose trial in renal transplant recipients.

The aim of this study was to analyze retrospectively and critically the different steps of the individual dose adjustment procedure employed in the concentration-controlled (CC) versus fixed-dose trial Apomygre, which showed that mycophenolate mofetil (MMF) dose adjustment using a limited sampling strategy significantly reduced the risk of treatment failures and acute rejection in renal transplants at one year posttransplantation. The number of AUCs performed during the study and circumstances of collection, time of blood sampling, Bayesian mycophenolic acid (MPA) area-under-the-curve (AUC) estimation procedures and physicians' compliance with MMF dose recommendations were retrospectively analyzed. 92% of AUCs scheduled over the study were actually performed. Sampling times were very well respected. Bayesian estimation of MPA exposure was done by the pharmacologists locally in accordance with the protocol instructions and the AUC estimates obtained were virtually all confirmed a posteriori. On the other hand, a second AUC estimated by multiple linear regression could only be provided for 84% of the profiles and showed a large overestimation with respect to Bayesian estimates for AUC values between 10 and 55mgh/L. In the CC arm, a very good physicians' compliance was observed (85%) and application of the dose recommendations led to higher values of AUCs (42.1+/-14.6mgh/L versus 36.7+/-16.3mgh/L, p=0.0035) and to more AUCs in the target range (69% versus 56%, p=0.0343) than when dose recommendations were not applied. By analyzing in detail the feasibility criteria of MMF Bayesian dose adjustment, this study highlighted the requirements for successful extrapolation of the Apomygre trial results to routine practice: (i) respect of the PK sampling time-windows; (ii) use of relevant tools for accurate drug exposure estimation and dose adjustment calculation; and (iii) good compliance of the physicians with regard to the recommended doses.

High rate of early virological failure with the once-daily tenofovir/lamivudine/nevirapine combination in naive HIV-1-infected patients.

BACKGROUND: The combination of one non-nucleoside reverse transcriptase inhibitor (NNRTI) with two nucleoside reverse transcriptase inhibitors is a validated first-line antiretroviral (ARV) therapy. The once-daily combination of lamivudine, tenofovirDF and nevirapine has not been evaluated in a clinical trial. METHODS: Randomized, open-label, multicentre, non-inferiority trial comparing lamivudine, tenofovirDF and nevirapine once daily (Group 2) with zidovudine/lamivudine and nevirapine twice daily (Group 1), in naive HIV-1-infected patients with a CD4 count <350/mm(3). We planned to enroll 250 patients. RESULTS: As of May 2006, 71 patients had been enrolled (35 in Group 1 and 36 in Group 2) and an unplanned interim analysis was done. The groups were comparable at baseline: median CD4 count was 195 and 191/mm(3) and median plasma viral load was 4.9 log(10) and 5.01 log(10), respectively, in Groups 1 and 2. Eight early non-responses (22.2%) were observed, all in Group 2, while two later viral rebounds occurred. Resistance genotypes for the nine Group 2 failing patients showed the mutations M184V/I (n = 3), K65R (n = 6), one or more NNRTI resistance mutations in all cases. At baseline, the nine Group 2 patients who failed had higher median plasma viral load (5.4 log(10)) and lower median CD4 count (110/mm(3)) than the other Group 2 patients (4.7 log(10), P = 0.002 and 223/mm(3), P = 0.004). Nevirapine trough concentrations were not different between the two groups, nor between patients with full viral suppression or those who failed in Group 2. Due to slow recruitment, and those results, the steering committee decided to stop the trial at 12 months. CONCLUSIONS: In ARV-naive HIV-1-infected patients, the once-daily lamivudine, tenofovirDF and nevirapine regimen resulted in a high rate of early virological failures. The reasons for the failures remain unclear.

Influence of schedule of administration on methotrexate penetration in brain tumours.

The influence of the administration schedule (intravenous (i.v.) bolus versus i.v. infusion) on the pharmacokinetics of methotrexate (MTX) in plasma and extracellular fluid (ECF) of a brain C6-glioma was investigated in rats. MTX concentrations were determined by high performance liquid chromatography (HPLC)-ultraviolet radiation (UV). MTX (50 mg/kg) was administered by i.v. bolus or i.v. infusion (4 h). Concentration-time profiles were fitted to a two-compartment open model. Maximum MTX concentrations ranged between 178 and 294 microgram/ml (i.v. bolus), and between 11 and 24 microgram/ml (i.v. infusion) in plasma. MTX rapidly entered the tumour tissue although its concentrations in the ECF were much lower than those observed in plasma for both modes of administration. In spite of an important interindividual variability, AUC(ECF) was approximately 5-fold higher and mean MTX penetration in tumour ECF (AUC(ECF)/AUC(Plasma)) was approximately 3-fold higher after i.v. bolus than after i.v. infusion administration. These results indicate that i.v. bolus administration schedules promote MTX delivery in brain tumour tissue.

Distribution of gacyclidine enantiomers after experimental spinal cord injury in rats: possible involvement of an active transport system.

The pharmacokinetics of gacyclidine enantiomers, a noncompetitive N-methyl-D-aspartate (NMDA) antagonist, were studied in plasma and spinal cord extracellular fluid (ECF) after experimental spinal cord injury in rats. Spinal cord trauma was produced by introducing an inflatable balloon in the dorsal subdural space. Upon implantation of microdialysis probes in spinal cord (T9) and intravenous (iv) bolus administration of (+/-)-gacyclidine (2.5 mg/kg), concentrations in plasma and ECF were monitored over 5 h and analyzed by a stereospecific gas chromatography-mass spectrometry (GC-MS) assay. In plasma, concentrations of (+)-gacyclidine were approximately 25% higher than those of (-)-gacyclidine over the duration of the experiment and decayed in parallel (t(1/2 alpha) approximately 7 min; t(1/2 beta) approximately 90 min) with no significant difference between the two enantiomers. Clearance (CL) and volume of distribution (Vd) of (-)-gacyclidine were approximately 20% higher than those of its optical antipode (CL: 285 versus 236 mL. kg(-1). min(-1); Vd(beta): 39.3 versus 31.2 l/kg). Protein binding (approximately 91%) was not stereoselective. In spinal cord ECF, both enantiomers were quantifiable within 10 min after drug administration, and their concentration remained stable over the duration of the experiment in spite of changing blood concentrations. Repeated iv bolus injections of gacyclidine did not modify these profiles. Areas under the curves (AUCs) of concentration in ECF versus time were similar for both enantiomers and not correlated with AUCs in plasma. Penetration of (-)-gacyclidine was, however, significantly higher (approximately 30%) than that of (+)-gacyclidine. In summary, the disposition of gacyclidine enantiomers is stereoselective. Both enantiomers exhibit a high affinity for spinal cord tissue, and the drug exchange between plasma and spinal cord ECF involves an active transport system. These findings contribute to the explanation of the discrepancy between drug concentrations in plasma and spinal cord ECF.

Pharmacokinetics of gacyclidine enantiomers in plasma and spinal cord after single enantiomer administration in rats.

The purpose of this study was to determine the pharmacokinetics of gacyclidine, a non-competitive NMDA antagonist, in plasma and spinal cord extracellular fluid (ECF) after IV administration of single enantiomers in rats. After implantation of microdialysis probes in spinal cord, concentrations in plasma and ECF dialysates were determined by a chiral GC/MS assay over 5 h after administration of either (+)-gacyclidine or (-)-gacyclidine (1.25 mg/kg). Plasma protein binding was estimated in vitro by equilibrium dialysis. Plasma concentrations decayed in parallel in a biphasic manner (t(1/2)alpha approximately 9 min; t(1/2)beta approximately 90 min) with no significant difference between the two enantiomers. Clearance of (+)-gacyclidine and (-)-gacyclidine (291 versus 275 ml/min per kg, respectively), volume of distribution (Vdbeta: 38 versus 40 l/kg), and protein binding (90 versus 89%) were not stereoselective. Both gacyclidine enantiomers were quantifiable in spinal cord ECF 10 min after drug administration and their concentrations remained stable over the duration of the experiment in spite of changing blood concentrations. Penetration of the two enantiomers in spinal cord ECF was similar although highly variable between animals. Exposure of spinal cord ECF was comparable for both enantiomers, and not correlated with plasma AUCs. This study showed the absence of any pharmacokinetic difference between the two enantiomers when administered individually, and no enantiomeric inversion. Both gacyclidine enantiomers penetrate rapidly and extensively into spinal cord ECF, and their distribution may involve an active transport system.

Arterio-venous ethanol levels in blood and plasma after intravenous injection in rabbits.

Arterio-venous ethanol concentrations in both whole blood and plasma were determined as a function of time in the rabbit. Following i.v. injection of 1.0 g/kg, both arterial and venous ethanol concentrations showed an abrupt decline occurring immediately after the end of the administration, followed by a pseudolinear phase that persisted for the length of the experiment. This work substantiates the arterio-venous ethanol concentration differences reported in the literature. It illustrates that equal arterial and venous ethanol concentrations may not be achieved readily after rapid i.v. injection. Moreover, it demonstrates a faster decay of ethanol concentrations in arterial than in venous plasma.

[Utilization of methylphenidate(Ritalin) in France]. / L'utilisation du méthylphénidate (Ritaline) en France.

Methylphenidate (Ritalin) is the only psychostimulant approved in France and indicated in attention deficit hyperactivity disorder in children over 6 years. It is under restricted prescription and distribution conditions. As such, it requires a hospital initiated prescription from either a neurology, psychiatry or pediatric specialist and it is covered by the "narcotics" schedule. The French Pharmacovigilance database spontaneous adverse drug reactions reporting, since it was approved in 1995, were analyzed. 21 adverse drug reactions were reported. In 16 cases, methylphenidate was suspected. They were generally non-serious, mild side effects and in most cases promptly resolved. These results do not suggest methylphenidate misuse in France or an overuse in between 1300 and 4000 treated children, to date. Until more information is available concerning the long-term effects of methylphenidate, and in order to limit misuse, inappropriate or overuse, the current prescription and dispensing regulation should be maintained in France, and could well be developed in other countries.

[Pharmacodynamic interest of ceftazidime continuous infusion vs intermittent bolus administration in patients with severe nosocomial pneumonia]. / Intérêt pharmacodynamique de la perfusion continue vs l'administration intermittente de ceftazidime dans les pneumonies nosocomiales sévères.

GOAL OF THE STUDY: It is well known today that the main determinant of beta-lactam antibiotics efficacy is the duration of the time that concentrations remain in excess of the minimum inhibitory concentration (MIC) of susceptible organism over the course of therapy. This prospective study aimed to evaluate the efficacy, in term of pharmacodynamic profile, of continuous infusion versus intermittent administration of ceftazidime in intensive care unit patients with severe nosocomial pneumonia. PATIENTS AND METHODS: 16 patients under mechanical ventilation with nosocomial pneumonia were randomised to receive either 60 mg/kg/day ceftazidime by constant rate infusion following a 20 mg/kg loading dose (Group A) or 20 mg/kg every 8 hour by intravenous bolus injection (Group B). In both groups, serial blood samples were collected during 48 hours (12 and 18 samples in Group A and B, respectively) after the start of drug administration. Plasma concentrations of ceftazidime were measured by high performance liquid chromatography. Based on our local bacteriological conditions, the pharmacodynamic profile of ceftazidime was assessed as the duration of time the plasma concentration remained above a desired target concentration of 20 mg/l for each regimen. RESULTS: The mean time (expressed as a percentage) for which plasma ceftazidime concentrations were above 20 mg/l was 100% for the continuous infusion group (Group A) and 56+/-33% for the intermittent administration group (Group B). CONCLUSION: These findings show that ceftazidime administered by continuous infusion in critically ill patients under mechanical ventilation with nosocomial pneumonia appears to substantially improve the pharmacodynamic profile of this beta-lactam compared to the intermittent regimen.

Bromism from daily over intake of bromide salt.

Bromide intoxication today is an infrequent disease, but preparations containing bromide are still available in nonprescription compounds, on the French market. We report a casewith bromide intoxication due to daily over intake (approximately 20 tablets per day; i.e. total elemental bromide intake approximately 6 g/day) of calcium bromo-galactogluconate (Calcibronat) for 1.5 months. A 30-year-old woman with a long history of psychotropic drug abuse was hospitalized in a psychiatric department for neuropsychological manifestations. She presented a seriously disturbed mental status with confusion, disorientation, auditory and visual hallucinations, and loss of short-time memory. A markedly increased serum bromide level of 1717 mg/L (21.5 mEq/L) measured on the first day after her admission confirmed the diagnosis of chronic bromism suspected based on her symptomatology. During her hospitalization, bromide plasma concentrations were measured and monitored using inductively coupled plasma mass spectrometry, a sensitive and very specific method. After withdrawal of the drug, the symptoms improved within 8 days. Serial bromide concentrations gradually declined throughout nearly 2 months of monitoring, until she was discharged from the hospital. We found an elimination half-life of bromide in blood of approximately of 10 days. This case demonstrates that, while today bromism occurs infrequently, it should still be included in the differential diagnosis of neuropsychiatric symptoms.

Effect of acute ethanol administration on toloxatone pharmacokinetics in rabbits.

The pharmacokinetics of toloxatone and ethanol were determined in plasma and cerebrospinal fluid of conscious rabbits. According to a cross-over design, rabbits (n = 5) randomly received on three separate occasions either toloxatone (5 mg/kg), ethanol (1 g/kg), or toloxatone and ethanol (5 mg/kg and 1 g/kg, respectively) by intravenous injection. Toloxatone and ethanol concentrations were measured by HPLC with UV detection and GC with flame ionization detection, respectively. Ethanol concentration profiles in plasma were characterized by a rapid decline occurring within the first 30 min after administration followed by a linear (zero-order) phase that persisted for the length of the experiment. The maximum ethanol elimination rate was 0.31+/-0.20 g/h x kg. Toloxatone concentrations in plasma and cerebrospinal fluid were characterized by a multiexponential decay with effective half-lives of 0.39+/-0.06 and 0.56+/-0.07 hr, respectively. Toloxatone passage through the blood brain barrier was rapid and important. Our results also demonstrate that acute ethanol administration had no effect on toloxatone pharmacokinetics and that toloxatone administration had no effect on ethanol pharmacokinetics.

Simultaneous determination of inulin and p-aminohippuric acid (PAH) in human plasma and urine by high-performance liquid chromatography.

Inulin and p-aminohippuric acid (PAH) clearances are used for the estimation of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). A simple and rapid high-performance liquid chromatography (HPLC) method with UV detection is described for the simultaneous determination of inulin and PAH in the same chromatogram in the plasma and urine of humans. Plasma and urine samples were hydrolyzed with perchloric acid (0.7%) in boiling water. The mobile phase consisted of 0.01 M potassium dihydrogenphosphate with 0.02 M tetramethylammonium chloride and o-phosphoric acid (pH 3)-acetonitrile (94:6, v/v), pumped at a rate of 1.2 ml min-1 on a C8 reversed-phase column. Tannic acid was used as the internal standard and UV detection at 285 nm was employed. The calibration curves were linear over the concentration range of 12.5-100 mg l-1 for inulin and 6.25-50 mg l-1 for PAH with determination coefficients greater than 0.997. The method is accurate (bias < 13%) and reproducible (intra- and inter-day relative standard deviation less than 11%), with a limit of quantitation of 12.5 mg l-1 and 6.25 mg l-1 for inulin and PAH, respectively. Analytical recoveries from urine and plasma were ranged from 81 to 108% for both compounds. This fully validated method, which allows the simultaneous determination of inulin and PAH clearances, is simple, rapid (total run time < 10 min) and requires only a 200 microliters plasma or urine sample.

Sensitive gas chromatographic-mass spectrometric method for the determination of gacyclidine in rat plasma and spinal cord dialyzates.

A sensitive gas chromatographic-mass spectrometric (GC-MS) procedure is described for the selective determination of gacyclidine (a non-competitive N-methyl-D-aspartate antagonist) in rat plasma and spinal cord dialyzates. It involves a single-step liquid-liquid extraction of plasma samples and dialyzates with hexane (pH 8.0) and the use of phencyclidine as an internal standard. The compounds were separated on a GC capillary column and specifically detected by MS in the selected-ion monitoring mode. Gacyclidine and its internal standard were monitored by using the fragment ions at m/z 206 and 200, respectively. The method was accurate and reproducible (intra- and inter-day reproducibility < 12%) with a limit of quantification of 1.6 ng ml-1 using 100 microliters plasma of dialyzate samples. The calibration curves for rat plasma and Ringer's solution were linear (r2 > 0.996) over a range from 1.6 to 200 ng ml-1. The extraction efficiency was close to 100%. This simple and rapid assay (total run time < 10 min) was validated for a pilot pharmacokinetic study in healthy rats after intravenous injection of a bolus dose of gacyclidine (2.5 mg kg-1).

Determination of gacyclidine enantiomers in human plasma by gas chromatography-mass spectrometry using selected-ion monitoring.

A sensitive gas chromatographic assay using mass selective-detection has been developed for the simultaneous quantitation of the enantiomers of (+/-)-gacyclidine (a non competitive N-methyl-D-aspartate antagonist) in human plasma. Gacyclidine enantiomers and phencyclidine (PCP), the internal standard, were extracted using a single-step liquid-liquid extraction with hexane at pH 8.0. Each enantiomer was separated on a chiral gas chromatography capillary column and specifically detected by mass spectrometry (MS) in selected-ion monitoring (SIM) mode. Gacyclidine enantiomers and PCP were monitored using the fragment ions at m/z 206 and 200, respectively. No interference was observed from endogenous components. The limit of quantitation (LOQ) for each enantiomer of gacyclidine was 300 pg/ml by using plasma samples of 500 microl. The calibration curves were linear (r2=0.998) over a range of 0.3125 to 20 ng/ml. The extraction efficiency was higher than 95% for both enantiomers. Intra- and inter-day bias were less than 10% at every standard curve concentration. Intra-day precision was less than 19% for (-)-gacyclidine and 15% for (+)-gacyclidine. Inter-day precision was below 15% for both enantiomers. The assay was validated for an enantioselective pharmacokinetic study in healthy male volunteers.

Distribution of gacyclidine enantiomers in spinal cord extracellular fluid.

PURPOSE: Determination of the pharmacokinetics of gacyclidine enantiomers, a non-competitive NMDA antagonist, in plasma and spinal cord extracellular fluid (ECF) of rats. METHODS: Implantation of microdialysis probes in spinal cord (T9). Serial collection of plasma samples and ECF dialysates over 5 hours after IV bolus administration of (+/-)-gacyclidine (2.5 mg/kg). Plasma protein binding determined in vivo by equilibrium dialysis. Chiral GC/ MS assay. RESULTS: Plasma concentrations of (+)-gacyclidine were approximately 25% higher than those of (-)-gacyclidine over the duration of the experiment in all animals. Plasma concentrations decayed in parallel in a biphasic manner (t1/2alpha approximately 9 min; t1/2beta approximately 90 min) with no significant difference between enantiomers. Clearance and volume of distribution of (-)-gacyclidine were approximately 20% higher than those of its optical antipode (CL: 248 vs 197 ml.kg(-1)x min(-1); Vdbeta: 31.6 vs 23.5 1/kg). Protein binding (approximately 90%) was not stereoselective. Both gacyclidine enantiomers were quantifiable in spinal cord ECF 10 min after drug administration and remained stable over the duration of the experiment in spite of changing blood concentrations. Penetration of (-)-gacyclidine was significantly higher (approximately 40%) than that of (+)-gacyclidine in all animals. Yet, exposure of spinal cord ECF was similar for both enantiomers, and not correlated with plasma AUCs. CONCLUSIONS: The disposition of gacyclidine enantiomers is stereoselective. Both enantiomers exhibit a high affinity for spinal cord tissue and their distribution may involve a stereoselective and active transport system. This hypothesis could also explain the discrepancy between drug concentrations in plasma and spinal cord ECE

Modified gas chromatographic-mass spectrometric assay for the determination of gacyclidine enantiomers in human plasma.

A modified method for the determination of gacyclidine enantiomers in human plasma by GC-MS with selected-ion monitoring using the deuterated derivative of gacyclidine (d3-gacyclidine) as internal standard was developed. Following a single-step liquid-liquid extraction with hexane, drug enantiomers were separated on a chiral fused-silica capillary column (CP-Chirasil-Dex; Chrompack). The fragment ion, m/z 266, was selected for monitoring d3-gacyclidine (retention times of 35.2 and 35.6 min for the (+)- and (-)-enantiomer, respectively) whereas the fragment ion, m/z 263, was selected for quantitation of gacyclidine (retention times of 35.4 and 35.9 min for the (+)- and (-)-enantiomer, respectively). The limit of quantitation for each enantiomer was 0.3 ng/ml, using 1 ml of sample, with a relative standard deviation (RSD) < 14% and a signal-to-noise ratio of 5. The extraction recovery of both gacyclidine enantiomers from human plasma was about 75%. The calibration curves were linear (r2 > 0.996) over the working range of 0.312 to 20 ng/ml. Within- and between-day RSD were < 9% at 5, 10 and 20 ng/ml, and < 16% at 0.312, 0.625, 1.25 and 2.5 ng/ml. Intraday and interday bias were less than 11% for both enantiomers. The chromatographic behavior of d3-gacyclidine remained satisfactory even after more than 500 injections. Applicability of this specific and stereoselective assay is demonstrated for a clinical pharmacokinetic study with racemic gacyclidine.

Pharmacokinetics of methotrexate in the extracellular fluid of brain C6-glioma after intravenous infusion in rats.

PURPOSE: Establishment of the pharmacokinetic profile of methotrexate (MTX) in the extracellular fluid (ECF) of a brain C6-glioma in rats. METHODS: Serial collection of plasma samples and ECF dialysates after i.v. infusion of MTX (50 or 100 mg/kg) for 4 h. HPLC assay. RESULTS: Histological studies revealed the presence of inflammation, edema, necrosis, and hemorrhage in most animals. In vivo recovery (reverse dialysis) was 10.8 +/- 5.3%. MTX concentrations in tumor ECF represented about 1-2% of the plasma concentrations. Rapid equilibration between MTX levels in brain tumor ECF and plasma. ECF concentrations almost reached steady-state by the end of the infusion (4 h), then decayed in parallel with those in plasma. Doubling of the dose did not modify MTX pharmacokinetic parameters (t1/2alpha, t1/2beta, MRT, fb, Vd, and CL(T)), except for a 1.7-fold increase of AUC(Plasma) and a 3.8-fold increase in AUC(ECF), which resulted in a 2.3-fold increase in penetration (AUC(ECF)/AUC(Plasma)). In spite of an important interindividual variability, a relationship between MTX concentrations in plasma and tumor ECF could be established from mean pharmacokinetic parameters. CONCLUSIONS: High plasma concentrations promote the penetration of MTX into brain tissue. However, free MTX concentrations in tumor ECF remain difficult to predict consistently.