Low Caspofungin Exposure in Patients in Intensive Care Units.

In critically ill patients, drug exposure may be influenced by altered drug distribution and clearance. Earlier studies showed that the variability in caspofungin exposure was high in intensive care unit (ICU) patients. The primary objective of this study was to determine if the standard dose of caspofungin resulted in adequate exposure in critically ill patients.

Substance use in individuals with mild to borderline intellectual disability: A comparison between self-report, collateral-report and biomarker analysis.

Background And Aims: Individuals with mild or borderline intellectual disability (MBID) are at risk of substance use (SU). At present, it is unclear which strategy is the best for assessing SU in individuals with MBID. This study compares three strategies, namely self-report, collateral-report, and biomarker analysis.

Longitudinal Analysis of the Effect of Inflammation on Voriconazole Trough Concentrations.

Voriconazole (VCZ) exhibits great inter- and intrapatient variability. The latter variation cannot exclusively be explained by concomitant medications, liver disease or dysfunction, and genetic polymorphisms in cytochrome P450 2C19 (CYP2C19). We hypothesized that inflammatory response in patients under VCZ medication might also influence this fluctuation in concentrations.

Voriconazole Therapeutic Drug Monitoring Practices in Intensive Care.

Background: Routine therapeutic drug monitoring of voriconazole seems to be beneficial. This study investigated the therapeutic drug monitoring practices in intensive care to derive possible recommendations for improvement.

Methods: A retrospective chart review was performed for patients aged ≥18 years who started treatment with voriconazole, which lasted for at least 3 days while being admitted to an intensive care unit to assess possible differences between the patients with and without voriconazole trough concentrations measured.

Subtherapeutic Posaconazole Exposure and Treatment Outcome in Patients With Invasive Fungal Disease.

Background: Posaconazole exposure seems to be subtherapeutic in some patients with invasive fungal disease. Due to the pharmacokinetic variability of posaconazole, therapeutic drug monitoring may help to optimize the efficacy of this antifungal drug.

Methods: A retrospective study of patients treated with posaconazole from January 2008 to April 2014 and for whom posaconazole serum concentrations were available was conducted.

Long-term exposure to circulating platinum is associated with late effects of treatment in testicular cancer survivors.

Background: The success of cisplatin-based (Platinol, Bristol-Myers Squibb Company, New York, NY, USA) chemotherapy for testicular cancer comes at the price of long-term and late effects related to healthy tissue damage. We assessed and modelled serum platinum (Pt) decay after chemotherapy and determined relationships between long-term circulating Pt levels and known late effects.

Patients And Methods: In 99 testicular cancer survivors, treated with cisplatin-based chemotherapy, serum and 24-h urine samples were collected during follow-up (1-13 years after treatment).

The relation of the number of hydrogen-bond acceptors with recoveries of immunosuppressants in DBS analysis.

Background: We investigated the influence of the number of hydrogen-bond acceptors on the recovery of immunosuppressant drugs and their structural analogs. This hypothesis was tested by evaluation of the extraction recoveries of tacrolimus, ascomycin, sirolimus, everolimus and temsirolimus with 12, 12, 13, 14 and 16 hydrogen-bond acceptors, respectively.

Results: With an increasing number of hydrogen-bond acceptors of sirolimus, everolimus and temsirolimus, a decrease in recoveries was found while ascomycin showed recoveries corresponding to those of tacrolimus.

The performance of five different dried blood spot cards for the analysis of six immunosuppressants.

Background: The relation between hematocrit, substance concentration, extraction recovery and spot formation of tacrolimus, sirolimus, everolimus, ascomycin, temsirolimus and cyclosporin A was investigated for Whatman 31 ET CHR, Whatman FTA DMPK-C, Whatman 903, Perkin Elmer 226 and Agilent Bond Elut DMS DBS cards.

Results & Discussion: We found that all DBS cards showed the same hematocrit and concentration-dependent recovery patterns for sirolimus, everolimus and temsirolimus. At high concentrations, the total hematocrit effects were much more pronounced than at low concentrations for tacrolimus, sirolimus, everolimus, ascomycin and temsirolimus.

What is the right blood hematocrit preparation procedure for standards and quality control samples for dried blood spot analysis?

Remco Koster is a research analyst and PhD candidate at the University Medical Center Groningen and University of Groningen. He has been working in the field of bioanalysis for over 13 years, where he has developed numerous analytical methods using LC-MS/MS. His main research focus is the influence of various matrices on the development and performance of analytical methods using LC-MS/MS.

Limited-sampling strategies for anidulafungin in critically ill patients.

Efficacy of anidulafungin is driven by the area under the concentration-time curve (AUC)/MIC ratio. Determination of the anidulafungin AUC along with MIC values can therefore be useful. Since obtaining a full concentration-time curve to determine an AUC is not always feasible or appropriate, limited-sampling strategies may be useful in adequately estimating exposure.

Inflammation is associated with voriconazole trough concentrations.

Voriconazole concentrations display a large variability, which cannot completely be explained by known factors. Inflammation may be a contributing factor, as inflammatory stimuli can change the activities and expression levels of cytochrome P450 isoenzymes. We explored the correlation between inflammation, reflected by C-reactive protein (CRP) concentrations, and voriconazole trough concentrations.

Five year results of an international proficiency testing programme for measurement of antifungal drug concentrations.

Objectives: Since 2007 the Dutch Association for Quality Assessment in Therapeutic Drug Monitoring (KKGT) has organized an international interlaboratory proficiency testing (PT) programme for measurement of antifungal drugs in plasma. We describe the 5 year results of the laboratories' performance.

Methods: Twice a year, laboratories received a set of blind plasma samples containing low or high concentrations of fluconazole, itraconazole, hydroxyitraconazole, posaconazole, voriconazole and flucytosine.

Simultaneous determination of rifampicin, clarithromycin and their metabolites in dried blood spots using LC-MS/MS.

Introduction: Rifampicin (RIF) and clarithromycin (CLR) are common drugs for the treatment of infections like Mycobacterium tuberculosis and Mycobacterium ulcerans. Treatment for these diseases are long-term and the individual pharmacokinetic variation, drug-drug interactions or non-adherence may introduce sub-therapeutic exposure or toxicity. The application of therapeutic drug monitoring (TDM) can be used to ensure efficacy and avoid toxicity.

Assessing the availability of the teratogenic drug isotretinoin outside the pregnancy prevention programme: a survey of e-pharmacies.

Purpose: The increase in online purchasing of medications raises safety concerns regarding teratogenic drugs. The use of the teratogenic drug 'isotretinoin' for women of childbearing age requires strict adherence to the Pregnancy Prevention Programme (PPP), a risk minimisation measure imposed on prescribers and users. We sought to determine how readily consumers can purchase isotretinoin online and the associated safety procedures and information.

Low but sufficient anidulafungin exposure in critically ill patients.

The efficacy of anidulafungin is driven by the area under the concentration-time curve (AUC)/MIC ratio. Patients in intensive care may be at risk for underexposure. In critically ill patients with an invasive Candida infection, the anidulafungin exposure and a possible correlation with disease severity or plasma protein levels were explored.

Simultaneous quantification of anidulafungin and caspofungin in plasma by an accurate and simple liquid chromatography tandem mass-spectrometric method.

Introduction: Echinocandins are a valuable addition for the treatment of invasive fungal infections, as they are efficacious, demonstrate low toxicity, and have limited drug-drug interactions. In specific clinical situations when altered pharmacokinetics can be expected or dosing guidelines are conflicting, it may be useful to measure concentrations. For this purpose, a liquid chromatography tandem mass-spectrometric method to measure anidulafungin and caspofungin in ethylenediaminetetraacetic acid plasma was developed.

Fast and highly selective LC-MS/MS screening for THC and 16 other abused drugs and metabolites in human hair to monitor patients for drug abuse.

Background: To facilitate the monitoring of drug abuse by patients, a method was developed and validated for the analysis of amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylphenidate, cocaine, benzoylecgonine, morphine, codeine, heroin, 6-monoacteylmorphine, methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), delta-9-tetrahydrocannabinol (THC), nicotine, and cotinine in human hair.

Methods: The hair preparation method contains a 3-step wash procedure with dichloromethane followed by a simultaneous hair pulverization and extraction procedure with disposable metal balls. The developed liquid chromatography tandem mass spectrometry method uses a single injection to detect and confirm all 17 abused drugs, including THC, within 4.

Application of sweat patch screening for 16 drugs and metabolites using a fast and highly selective LC-MS/MS method.

Background: To facilitate the monitoring of drug abuse by patients, a method was developed and validated for fast and highly selective screening for amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylphenidate, cocaine, benzoylecgonine, morphine, codeine, heroin, 6-monoacteylmorphine, methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, nicotine, and cotinine in PharmCheck sweat patches. The analysis of sweat patches would provide a noninvasive alternative matrix to urine or blood samples.

Methods: The sweat patches were extracted during vigorous shaking for 10 minutes with 1.

Fast LC-MS/MS analysis of tacrolimus, sirolimus, everolimus and cyclosporin A in dried blood spots and the influence of the hematocrit and immunosuppressant concentration on recovery.

We developed a method for the analysis of four immunosuppressants in dried blood spot (DBS) samples to facilitate therapeutic drug monitoring for transplant patients outside the hospital. An 8mm disc from the central part of the DBS was punched, extracted and followed by LC-MS/MS analysis. The method was validated with ranges from 1.

Pharmacokinetic variability of clarithromycin and differences in CYP3A4 activity in patients with cystic fibrosis.

Background: To investigate the correlation between CYP3A4/5 activity and clarithromycin metabolism, and between CYP3A activity and CYP3A genotype.

Methods: This is an open-label, prospective pharmacokinetic study evaluating CYP3A activity using The Erythromycin Breath Test. Eight blood samples were collected within 12h after clarithromycin 500 mg was administered orally.

Dried blood spot analysis suitable for therapeutic drug monitoring of voriconazole, fluconazole, and posaconazole.

Invasive aspergillosis and candidemia are important causes of morbidity and mortality in immunocompromised and critically ill patients. The triazoles voriconazole, fluconazole, and posaconazole are widely used for the treatment and prophylaxis of these fungal infections. Due to the variability of the pharmacokinetics of the triazoles among and within individual patients, therapeutic drug monitoring is important for optimizing the efficacy and safety of antifungal treatment.

Clinical validation of the analysis of linezolid and clarithromycin in oral fluid of patients with multidrug-resistant tuberculosis.

Linezolid plays an increasingly important role in the treatment of multidrug-resistant tuberculosis (MDR-TB). However, patients should be carefully monitored due to time- and dose-dependent toxicity. Clarithromycin plays a more modest role.

Clarithromycin increases linezolid exposure in multidrug-resistant tuberculosis patients.

The use of linezolid for the treatment of multidrug-resistant tuberculosis is limited by dose- and time-dependent toxicity. Recently, we reported a case of pharmacokinetic drug-drug interaction between linezolid and clarithromycin that resulted in increased linezolid exposure. The aim of this prospective pharmacokinetic study is to quantify the effect of clarithromycin on the exposure of linezolid.