A single LC-tandem mass spectrometry method for the simultaneous determination of 14 antimalarial drugs and their metabolites in human plasma.

Among the various determinants of treatment response, the achievement of sufficient blood levels is essential for curing malaria. For helping us at improving our current understanding of antimalarial drugs pharmacokinetics, efficacy and toxicity, we have developed a liquid chromatography-tandem mass spectrometry method (LC-MS/MS) requiring 200mul of plasma for the simultaneous determination of 14 antimalarial drugs and their metabolites which are the components of the current first-line combination treatments for malaria (artemether, artesunate, dihydroartemisinin, amodiaquine, N-desethyl-amodiaquine, lumefantrine, desbutyl-lumefantrine, piperaquine, pyronaridine, mefloquine, chloroquine, quinine, pyrimethamine and sulfadoxine). Plasma is purified by a combination of protein precipitation, evaporation and reconstitution in methanol/ammonium formate 20mM (pH 4.0) 1:1. Reverse-phase chromatographic separation of antimalarial drugs is obtained using a gradient elution of 20mM ammonium formate and acetonitrile both containing 0.5% formic acid, followed by rinsing and re-equilibration to the initial solvent composition up to 21min. Analyte quantification, using matrix-matched calibration samples, is performed by electro-spray ionization-triple quadrupole mass spectrometry by selected reaction monitoring detection in the positive mode. The method was validated according to FDA recommendations, including assessment of extraction yield, matrix effect variability, overall process efficiency, standard addition experiments as well as antimalarials short- and long-term stability in plasma. The reactivity of endoperoxide-containing antimalarials in the presence of hemolysis was tested both in vitro and on malaria patients samples. With this method, signal intensity of artemisinin decreased by about 20% in the presence of 0.2% hemolysed red-blood cells in plasma, whereas its derivatives were essentially not affected. The method is precise (inter-day CV%: 3.1-12.6%) and sensitive (lower limits of quantification 0.15-3.0 and 0.75-5ng/ml for basic/neutral antimalarials and artemisinin derivatives, respectively). This is the first broad-range LC-MS/MS assay covering the currently in-use antimalarials. It is an improvement over previous methods in terms of convenience (a single extraction procedure for 14 major antimalarials and metabolites reducing significantly the analytical time), sensitivity, selectivity and throughput. While its main limitation is investment costs for the equipment, plasma samples can be collected in the field and kept at 4 degrees C for up to 48h before storage at -80 degrees C. It is suited to detecting the presence of drug in subjects for screening purposes and quantifying drug exposure after treatment. It may contribute to filling the current knowledge gaps in the pharmacokinetics/pharmacodynamics relationships of antimalarials and better define the therapeutic dose ranges in different patient populations.

Swallowing difficulties with oral drugs among polypharmacy patients attending community pharmacies.

Background Swallowing difficulties are common and can affect patients' ability to take solid oral dosage forms, thus compromising medication adherence. Strategies developed by patients to overcome such difficulties while taking medicines have seldom been described. Objective To determine prevalence and characteristics of swallowing difficulties among primary care patients attending their community pharmacies; to explore strategies developed by patients to overcome their difficulties, and health professionals' awareness of these problems. Setting Prospective study with a semi-structured questionnaire in random community pharmacies located in two Swiss regions. Method In each pharmacy, an interviewer asked 16 questions to each consecutive patient (18 years and older) with a prescription for at least 3 different solid oral forms. Main outcome measure Quantification of number of patients with swallowing difficulties and detailed description of difficulties. Results Among 122 pharmacies, 59 (48 %) accepted to join the study and 410 patients were enrolled. Thirty-seven patients (9.0 %) reported ongoing swallowing difficulties, while 55 patients (13.4 %) reported past difficulties. For the majority of patients, difficulties occurred at each single dose (83.7 %), with a single medication (59.8 %) and lasted for less than 12 months (53.8 %). Number of tablets was not the main trigger. Swallowing difficulties impaired extremely daily life in 12 % of the patients. Intentional non adherence (23 % of patients) and altering the oral dose formulation were the most common and potentially harmful strategies used by patients to overcome their swallowing difficulties. According to the patients, pharmacists and physicians rarely inquired about their swallowing difficulties. Conclusion We report a fairly high prevalence of swallowing difficulties in polypharmacy patients attending their community pharmacies. Pharmacists have to interview patients on their swallowing difficulties in a more systematic way, support patients in finding solutions and refer them to their physician if necessary to ensure continuity in care.

Use of neuroenhancement drugs: prevalence, frequency and use expectations in Switzerland

Objective: The present study investigates the use expectations, prevalence and frequency of neuroenhancement drug (ND) use among the Swiss male population, separating college students from others. Methods: Young Swiss men were invited to participate in the Cohort Study on Substance Use Risk Factors. A total of 5,967 participants responded to questions on six types of NDs (wakefulness medication, antidepressants, Alzheimer's disease medication, Parkinson's disease medication, attention deficit-hyperactivity disorder (ADHD) medication, and beta-blockers). The frequency of use depending on five expectations (to enhance wakefulness, attention, memory, concentration and stress reduction) was analyzed for a twelve-month period. Results: (1) About 3% of the sample indicated use of at least one ND; (2) ADHD medication was the most prevalent; (3) The type of ND preferred differed depending on academic status (4). Quantitatively, over the year, college student users used ND much less frequently than other users. Conclusions: Prevalence of ND use is low in Switzerland relative to other countries such as the United States. Patterns of ND use differed depending on academic status, suggesting that while college student ND users tended to do so rarely (probably to enhance cognitive abilities for exams), non-college male users used other NDs more frequently (probably to "get high").

Drug monographs on drugs which are frequently analysed in the context of Therapeutic Drug Monitoring = Arzneimittel-Monographien für Medikamente, die regelmässig im Rahmen des Therapeutic Drug Monitorings analysiert werden

In addition to the monographs which were published last year by the working group "Drug Monitoring" of the Swiss Society of Clinical Chemistry (SSCC) [1], new monographs have been written. The aim of these monographs is to give an overview of the most important information necessary for ordering a drug analysis or interpreting the results. Therefore, the targeted readers comprise laboratory health professionals and all receivers of laboratory reports. There is information provided on the indication for therapeutic drug monitoring, protein binding, metabolic pathways and enzymes involved, elimination half-life and elimination routes, and on therapeutic or toxic concentrations. Preanalytical considerations are of particular importance for therapeutic drug monitoring. Therefore, information is provided regarding a reasonable timing for the determination of drug concentrations as well as steady-state concentrations after changing the dose. Furthermore, the stability of the drug and its metabolite(s) after blood sampling is described. For readers with a specific interest in drug analysis, references to important publications are given. The number of monographs will be continuously enlarged. The updated files are presented on the homepage of the SSCC (www.sscc.ch).

The impact of newer antiepileptic drugs in the treatment of status epilepticus

Purpose: Newer antiepileptic drugs (AED) are increasingly prescribed, and seem to have a comparable efficacy as the classical AED in patients living with epilepsy; however, their impact on status epilepticus (SE) prognosis has received little attention. Method: In our prospective SE registry (2006-10) we assessed the use of newer AED (for this purpose: levetiracetam, pregabalin, topiramate, lacosamide) over time, and its relationship to outcome (return to clinical baseline conditions, new handicap, or death). We adjusted for recognized SE outcome predictors (Status Epilepticus Severity Score, STESS; potentially fatal etiology), and the use of >2 AED for a given SE episode. Result: Newer AED were used more often towards the end of the study period (42% versus 30% episodes), and more frequently in severe and difficult to treat episodes. However, after adjustment for SE etiology, STESS, and medication number, newer AED resulted independently related to reduced likelihood of return to baseline (p < 0.01), but not to increased mortality. STESS and etiology were robustly related to both outcomes (p < 0.01 for each), while prescription of >2 AED was only related to lower chance of return to baseline (p = 0.03). Conclusion: Despite increase in the use of newer AED, our findings suggest that SE prognosis has not been improved. This appears similar to recent analyses on patients with refractory epilepsy, and corroborates the hypothesis that SE prognosis is mainly determined by its biological background. Since newer AED are more expensive, prospective trials showing their superiority (at least regarding side effects) appear mandatory to justify their use in this setting.

Newer antiepileptic drugs in the treatment of status epilepticus: impact on prognosis

Background: Newer antiepileptic drugs (AED) are increasingly prescribed, and seem to have a comparable efficacy as the classical AED, but are better tolerated. Very scarce data exist regarding their prognostic impact in patients with status epilepticus (SE). We therefore analyzed the evolution of prescription of newer AED between 2006-2010 in our prospective SE database, and assessed their impact on SE prognosis.¦Methods: We found 327 SE episodes occurring in 271 adults. The use of older versus newer AED (levetiracetam, pregabalin, topiramate, lacosamide) and its relationship to outcome (return to clinical baseline conditions, new handicap, or death) were analyzed. Logistic regression models were applied to adjust for known SE outcome predictors.¦Results: We observed an increasing prescription of newer AED over time (30% of patients received them at the study beginning, vs. 42% towards the end). In univariate analyses, patients treated with newer AED had worse outcome than those treated with classical AED only (19% vs 9% for mortality; 33% vs 64% for return to baseline, p<0.001). After adjustment for etiology and SE severity, use of newer AED was independently related to a reduced likelihood of return to baseline (p<0.001), but not to increased mortality.¦Conclusion: This retrospective study shows an increase of the use of newer AED for SE treatment, but does not suggest an improved prognosis following their prescription. Also in view of their higher price, well-designed, prospective assessments analyzing their impact on efficacy and tolerability should be conducted before a widespread use in SE.

Ampakine CX546 bolsters energetic response of astrocytes: a novel target for cognitive-enhancing drugs acting as alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor modulators.

Glutamate was previously shown to enhance aerobic glycolysis i.e. increase glucose utilization and lactate production with no change in oxygen levels, in mouse cortical astrocytes by a mechanism involving glutamate uptake. It is reported here that a similar response is produced in both hippocampal and cerebellar astrocytes. Application of the cognitive-enhancing drug CX546 promoted further enhancement of glucose utilization by astrocytes from each brain area following glutamate exposure. alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors represent the purported molecular target of cognitive-enhancing drugs such as CX546, and the presence of AMPA receptor subunits GluR1-4 was evidenced in astrocytes from all three regions by immunocytochemistry. AMPA itself did not stimulate aerobic glycolysis, but in the presence of CX546, a strong enhancement of glucose utilization and lactate production was obtained in cortical, hippocampal and cerebellar astrocytes. The effect of CX546 was concentration-dependent, with an EC(50) of 93.2 microm in cortical astrocytes. AMPA-induced glucose utilization in the presence of CX546 was prevented by the AMPA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and the negative modulator GYKI 52466. In addition, the metabolic effect of CX546 in the presence of AMPA was mimicked by the AMPA receptor modulator cyclothiazide. Our data suggest that astrocyte energetics represents a novel target for cognitive-enhancing drugs acting as AMPA receptor modulators.

Hypertension artérielle réfractaire au traitement due au syndrome d'apnées du sommeil et à la prise de médicaments [Obstructive sleep apnea and drugs as causes of treatment-resistant hypertension].

Treatment-resistant hypertension is still common despite the availability of several types of antihypertensive agents acting by different mechanisms. The existence of refractory hypertension should lead to rule out "white-coat hypertension", poor adherence to prescribed drugs as well as classical causes of secondary hypertension such as renal artery stenosis, primary aldosteronism, pheochromocytoma and renal disease. It is also important to consider the possible existence of obstructive sleep apnea or the regular intake of vasopressive drugs or substances.

Effects of immunosuppressive drugs on T helper cells subsets and potential to promote tolerance in a stringent experimental transplantation model.

To achieve the goal of sustained donor-specifi c transplantation (Tx) tolerance, research efforts are now focusing on therapies based on specifi c cell subsets with regulatory properties. We and others have previously highlighted the therapeutic potential of naturally occurring CD4+CD25+Foxp3+ regulatory T cells (nTreg) in promoting long-term graft acceptance. Using more stringent experimental Tx models, we were however confronted to limitations. Indeed, while the transfer of antigenspecifi c nTreg promoted long-term MHC-mismatched skin allograft acceptance in lymphopenic mice in the absence of any immunosuppressive drug, allograft survival was only slightly prolonged when nTreg were transferred alone into non-lymphopenic mice. This suggested that in more stringent conditions, adjuvant therapies may be needed to effectively control alloreactive T cells (Teff). Whether and how the expansion of the Treg pool could be best combined with current immunosuppressive regimens in clinical settings remains to be defi ned. In this study, we have used in vitro assays and an in vivo skin Tx model to investigate the effects of various immunosuppressive drugs on the survival, proliferation and effector function of Teff and nTreg in response to alloantigens. Teff proliferation was inhibited in a dose-dependent manner by rapamycin and cyclosporine A, while anti-CD154 mAb only marginally affected Teff survival, proliferation and effector fucntion in vitro. Rapamycin promoted apoptosis of Teff as compared to nTreg that were more resistant in the presence of IL-2. In vivo, the transfer and/or expansion of Treg could be advantageously combined with rapamycin and anti-CD154 mAb treatment to signifi cantly prolong MHC-mismatched skin allografts survival in non-lymphopenic recipients. Taken together our data indicate that immunosuppressive drugs differentially target T-cell subsets and that some regimens could promote Treg expansion while controlling the Teff pool in response to alloantigens.

Concurrent versus simultaneous use of alcohol and non-medical use of prescription drugs: is simultaneous use worse for mental, social, and health issues?

Abstract This study investigated the difference between concurrent and simultaneous use of alcohol and non-medical use of prescription drugs (NMUPD) in relation to mental, social, and health issues. The 544 study participants of the Swiss ongoing Cohort Study on Substance Use Risk Factors (C-SURF) had a combined use of alcohol with NMUPD during the previous 12 months. Alcohol-related problems (i.e., dependence and consequences), as well as mental, social, and health concerns (i.e., depression, general mental/physical health, and social/health consequences), were assessed. The simultaneous use of alcohol and NMUPD proved to be a greater risk factor for mental, social, and health issues than concurrent use. This study adds information regarding simultaneous polydrug use, which results in distinct effects compared to concurrent use, including important social, psychosocial, and health-related consequences.