Update zum Therapeutic Drug Monitoring und zu pharmakogenetischen Untersuchungen zur Optimierung der Therapie mit Psychopharmaka

Das Therapeutic Drug Monitoring von Psychopharmaka wird in zahlreichen Laboratorien immer häufiger durchgeführt, ebenso wie pharmakogenetische Untersuchungen. In diesem Übersichtsartikel wurde die dazugehörige Literatur aus den Jahren 2011 und 2012 zusammengefasst. Die Guidelines der AGNP enthalten alle wichtigen Informationen, die notwendig sind, um Konzentrationen von Psychopharmaka richtig zu interpretieren. Die Bestimmung von Serotonin im Urin könnte ein Marker zur Beurteilung des Therapieerfolgs von Antidepressiva darstellen. Mit Hilfe der Positronen-Emissions-Tomographie konnten Korrelationen zwischen der Belegung der Zielrezeptoren im Gehirn und der Medikamentenkonzentration ermittelt werden. Der Einfluss des Alters auf die Medikamentenkonzentrationen wurde kontrovers beschrieben, wohingegen Frauen in allen Arbeiten bei einigen Antidepressiva einen verlangsamten Metabolismus und erhöhte Serumkonzentrationen aufwiesen. In mehreren Publikationen wurden Multianalytenverfahren für die Bestimmung von Psychopharmaka beschrieben, die trotz unterschiedlicher Methoden sehr gute Validierungsresultate aufwiesen. Bei allen Methoden gibt es einige Substanzen, deren Validationsresultate nur knapp genügten, was auf die Tatsache zurückgeführt werden muss, dass bei Multianalytenverfahren nicht alle Analyten optimal nachgewiesen werden können. Pharmakogenetische Untersuchungen haben noch keinen festen Platz bei der Verordnung von Psychopharmaka. Dies beruht unter anderem auf dem Fehlen von Evidenz-basierten Daten aus großen randomisierten Studien und dem Fehlen von entsprechend standardisierten analytischen Methoden, die die gesamte genetische Variabilität nachweisen könne

Laboratory diagnostics in acute poisoning: critical overview

Laboratory diagnostics play an important role in the treatment of patients with acute poisoning. The classical clinical chemistry and hematology tests help initiate supportive treatment, and specialized methods enable elucidation of the poisons involved. In this context, two different analytical approaches are used: the direct quantification of a potentially involved compound or screening procedures looking either for a distinct drug class or a wide variety of different compounds. The most common tests are immunoassays, which have the advantage of being fast and highly automated. These assays are available for the substances which are often involved in intoxications. The other analytical technique which is widely used is hyphenated chromatography consisting of either high-performance liquid chromatography or gas chromatography as chromatographic systems and detection with a diode-array or mass spectrometer. Whereas gas chromatography mass spectrometry screening procedures have been known for a long time, liquid chromatography mass spectrometry screening methods are now developed by different research groups and still need to prove their reliability. In this review, the different analytical technologies and their application will be discussed. Clin Chem Lab Med 2010;48:1381-

Diagnostic efficiency of different amphetamine screening tests - the search for an optimal cutoff

Increased use of designer drugs (amphetamines and amphetamine-like substances) raises the need for fast screening tests in urine in clinical settings, workplace and drug rehabilitation. Immunological assays currently used are subject to unwanted crossreactivities, partly depending on the cutoff concentrations used. The values recommended in Europe and the USA are 500 and 1000 ng/ml, respectively. In Switzerland, the recommended concentration of 300 ng/ml results in a high rate of false-positive urine samples and expensive, time-consuming confirmation testing. Using the Abbott Axsym analyzer, we found numerous false positives from patients in rehabilitation centers due to concomitant medication. Therefore, the diagnostic sensitivity and specificity of the Abbott test at different cutoff concentrations and the sensitivity of the Roche Cobas Integra, Beckman Synchron and Biosite Triage point-of-care test were examined. HPLC Bio-Rad Remedi was chosen as the method of higher hierarchical order. The specificity of the Axsym analyzer (300 ng/ml) was 86%. At 500 ng/ml or 1000 ng/ml the specificity was increased to 99 or 100%, respectively, while the sensitivity only decreased from 97 to 91 or 81%, respectively. In summary, the cutoff concentration for amphetamine screening tests should not be below 500 ng/ml to avoid a high rate of false-positive result

Development and validation of an LC-MS/MS method to quantify lysergic acid diethylamide (LSD), iso-LSD, 2-oxo-3-hydroxy-LSD, and nor-LSD and identify novel metabolites in plasma samples in a controlled clinical trial

Lysergic acid diethylamide (LSD) is a widely used recreational drug. The aim of this study was to develop and validate a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the quantification of LSD, iso-LSD, 2-oxo-3-hydroxy LSD (O-H-LSD), and nor-LSD in plasma samples from 24 healthy subjects after controlled administration of 100 μg LSD in a clinical trial. In addition, metabolites that have been recently described in in vitro studies, including lysergic acid monoethylamide (LAE), lysergic acid ethyl-2-hydroxyethylamide (LEO), 2-oxo-LSD, trioxylated-LSD, and 13/14-hydroxy-LSD, should be identified.; Separation of LSD and its metabolites was achieved on a reversed phase chromatography column after turbulent-flow online extraction. For the identification and quantification, a triple-stage quadrupole LC-MS/MS instrument was used.; The validation data showed slight matrix effects for LSD, iso-LSD, O-H-LSD, or nor-LSD. Mean intraday and interday accuracy and precision were 105%/4.81% and 105%/4.35% for LSD, 98.7%/5.75% and 99.4%/7.21% for iso-LSD, 106%/4.54% and 99.4%/7.21% for O-H-LSD, and 107%/5.82% and 102%/5.88% for nor-LSD, respectively. The limit of quantification was 0.05 ng/mL for LSD, iso-LSD, and nor-LSD and 0.1 ng/mL for O-H-LSD. The limit of detection was 0.01 ng/mL for all compounds.; The method described herein was accurate, precise, and the calibration range within the range of expected plasma concentrations. LSD was quantified in the plasma samples of the 24 subjects of the clinical trial, whereas iso-LSD, O-H-LSD, nor-LSD, LAE, LEO, 13/14-hydroxy-LSD, and 2-oxo-LSD could only sporadically be detected but were too low for quantification

Bile Acid Metabolites in Serum: Intraindividual Variation and Associations with Coronary Heart Disease, Metabolic Syndrome and Diabetes Mellitus

Bile acids (BAs) regulate glucose and lipid metabolism. In longitudinal and case-control-studies, we investigated the diurnal variation of serum concentrations of the 15 major BAs as well as the biosynthetic precursor 7α-hydroxy-4-cholesten-3-one (C4) and their associations, respectively, with coronary artery disease (CAD), diabetes mellitus type 2 (T2DM), and non-diabetic metabolic syndrome (MetS). In hourly taken blood samples of four healthy probands, the intraindividual 24 h variation of C4, conjugated and unconjugated BAs ranged from 42% to 72%, from 23% to 91%, and from 49% to 90%, respectively. Conjugated BA concentrations mainly increased following food intake. Serum levels of C4 and unconjugated BAs changed with daytime with maxima varying interindividually between 20h00 and 1h00 and between 3h00 and 8h00, respectively. Comparisons of data from 75 CAD patients with 75 CAD-free controls revealed no statistically significant association of CAD with BAs or C4. Comparisons of data from 50 controls free of T2DM or MetS, 50 MetS patients, and 50 T2DM patients revealed significantly increased fasting serum levels of C4 in patients with MetS and T2DM. Multiple regression analysis revealed body mass index (BMI) and plasma levels of triglycerides (TG) as independent determinants of C4 levels. Upon multivariate and principle component analyses the association of C4 with T2DM and/or MetS was not independent of or superior to the canonical MetS components. In conclusion, despite large intra- and interindividual variation, serum levels of C4,are significantly increased in patients with MetS and T2DM but confounded with BMI and TG

Presentations due to acute toxicity of psychoactive substances in an urban emergency department in Switzerland: a case series.

BACKGROUND Although the recreational use of psychoactive substances is common there is only limited systematic collection of data on acute drug toxicity or hospital presentations, in particular regarding novel psychoactive substances (NPS) that have emerged on the illicit market in the last years. METHODS We included all cases presenting at the emergency department (ED) of the University Hospital of Basel, Switzerland, between October 2014 and September 2015 with acute toxicity due to self-reported recreational drug use or with symptoms/signs consistent with acute toxicity. Intoxications were confirmed using immunoassays and LC-MS/MS, detecting also novel psychoactive substances. RESULTS Among the 50'624 attendances at the ED, 210 were directly related to acute toxicity of recreational drugs. The mean patient age was 33 years and 73 % were male. Analytical drug confirmation was available in 136 cases. Most presentations were reportedly related to cocaine (33 %), cannabis (32 %), and heroin (14 %). The most commonly analytically detected substances were cannabis (33 %), cocaine (27 %), and opioids excluding methadone (19 %). There were only two NPS cases; a severe intoxication with paramethoxymethamphetamine (PMMA) in combination with other substances and an intoxication of minor severity with 2,5-dimethoxy-4-propylphenethylamine (2C-P). The most frequent symptoms were tachycardia (28 %), anxiety (23 %), nausea or vomiting (18 %), and agitation (17 %). Severe complications included two fatalities, two acute myocardial infarctions, seizures (13 cases), and psychosis (six cases). Most patients (76 %) were discharged home, 10 % were admitted to intensive care, and 2 % were referred to psychiatric care. CONCLUSION Most medical problems related to illicit drugs concerned cocaine and cannabis and mainly included sympathomimetic toxicity and/or psychiatric disorders confirming data from the prior year. Importantly, despite the dramatic increase in various NPS being detected in the last years, these substances were infrequently associated with ED presentations compared with classic recreational drugs

Quantification of the 15 major human bile acids and their precursor 7α-hydroxy-4-cholesten-3-one in serum by liquid chromatography-tandem mass spectrometry

Bile acids are increasingly gaining attention since they were discovered to be activators of the transcription factor farnesoid X receptor (FXR) in addition to their well-established role in dietary lipid emulsification. Moreover, the differential activation potency of bile acids on FXR, which is due to structural variation of the ligands, generates the need for new analytical tools that are sensitive and specific enough to quantify the individual species of this complex class of compounds. Because bile acids undergo enterohepatic circulation, the additional assessment of a bile acid precursor as a marker for bile acid biosynthesis is used to differentiate between newly synthesised bile acids and bile acids reabsorbed from the intestine. This paper describes two new methods using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the quantification of the major unconjugated bile acids in human serum (cholic acid, chenodeoxycholic acid, deoxycholic acid, lithocholic acid and ursodeoxycholic acid) with their glycine- and taurine-conjugates as well as their precursor 7α-hydroxy-4-cholesten-3-one (C4). Intra- and inter-day variation was less than 12% and accuracy was between 84% and 102% for all analytes. Extraction recovery was between 78% and 100% for the bile acids whereas it was 62% for C4 and limit of quantification values ranged from 2nmol/l to 50nmol/l for all compounds. These two methods have the practical advantage of requiring low sample volume (100μl serum for each method) and identical eluents, stationary phase as well as ionisation technique, so that they can be used in a combined way. Moreover, they provide information on the composition of the bile acid pool on one hand and on the relative amount of newly synthesised bile acids on the other, which taken together, gives new insights in the investigation of bile acid metabolism

Clinical effect of obesity on N-terminal pro-B-type natriuretic peptide cut-off concentrations for the diagnosis of acute heart failure

AIMS Obese patients have lower natriuretic peptide concentrations. We hypothesized that adjusting the concentration of N-terminal pro-B-type natriuretic peptide (NT-proBNP) for obesity could further increase its clinical utility in the early diagnosis of acute heart failure (AHF). METHODS AND RESULTS This hypothesis was tested in a prospective diagnostic study enrolling unselected patients presenting to the emergency department with acute dyspnoea. Two independent cardiologists/internists centrally adjudicated the final diagnosis using all individual patient information including cardiac imaging. NT-proBNP plasma concentrations were applied: first, using currently recommended cut-offs; second, using cut-offs lowered by 33% with body mass index (BMI) of 30-34.9 kg/m$^{2}$ and by 50% with BMI ≥ 35 kg/m$^{2}$ . Among 2038 patients, 509 (25%) were obese, of which 271 (53%) had AHF. The diagnostic accuracy of NT-proBNP as quantified by the area under the receiver-operating characteristic curve was lower in obese versus non-obese patients (0.890 vs. 0.938). For rapid AHF rule-out in obese patients, the currently recommended cut-off of 300 pg/ml achieved a sensitivity of 96.7% (95% confidence interval [CI] 93.8-98.2%), ruling out 29% of patients and missing 9 AHF patients. For rapid AHF rule-in, the age-dependent cut-off concentrations (age 75 years: 1800 pg/ml) achieved a specificity of 84.9% (95% CI 79.8-88.9%). Proportionally lowering the currently recommended cut-offs by BMI increased sensitivity to 98.2% (95% CI 95.8-99.2%), missing 5 AHF patients; reduced the proportion of AHF patients remaining in the 'gray zone' (48% vs. 26%; p = 0.002), achieving a specificity of 76.5% (95% CI 70.7-81.4%). CONCLUSIONS Adjusting NT-proBNP concentrations for obesity seems to further increase its clinical utility in the early diagnosis of AHF

Garlic extract induces intestinal P-glycoprotein, but exhibits no effect on intestinal and hepatic CYP3A4 in humans

Garlic extracts have been shown to decrease drug exposure for saquinavir, a P-glycoprotein and cytochrome P450 3A4 substrate. In order to explore the underlying mechanisms and to study the effects of garlic on pre-systemic drug elimination, healthy volunteers were administered garlic extract for 21 days. Prior to and at the end of this period, expression of duodenal P-glycoprotein and cytochrome P450 3A4 protein were assayed and normalized to villin, while hepatic cytochrome P450 3A4 function and simvastatin, pravastatin and saquinavir pharmacokinetics were also evaluated. Ingestion of garlic extract increased expression of duodenal P-glycoprotein to 131% (95% CI, 105-163%), without increasing the expression of cytochrome P450 3A4 which amounted to 87% (95% CI, 67-112%), relative to baseline in both cases. For the erythromycin breath test performed, the average result was 96% (95% CI, 83-112%). Ingestion of garlic extract had no effect on drug and metabolite AUCs following a single dose of simvastatin or pravastatin, although the average area under the plasma concentration curve (AUC) of saquinavir decreased to 85% (95% CI, 66-109%), and changes in intestinal P-glycoprotein expression negatively correlated with this change. In conclusion, garlic extract induces intestinal expression of P-glycoprotein independent of cytochrome P450 3A4 in human intestine and liver