Pharmacokinetics and Pharmacodynamics of Inhaled Nicotine Salt and Free-Base Using an E-cigarette: A Randomized Crossover Study.

INTRODUCTION: Popular "pod-style" e-cigarettes commonly use nicotine salt-based e-liquids that cause less irritation when inhaled and can deliver higher nicotine concentrations than free-base nicotine. This study investigated the pharmacokinetic and pharmacodynamic effects of different nicotine formulations (salt vs. free-base) and concentrations that might influence systemic nicotine absorption and appeal of e-cigarettes. AIMS AND METHODS: In this randomized, double-blind, within-subject crossover study, 20 non-nicotine-naïve participants were switched among three e-liquids (free-base nicotine 20 mg/mL, nicotine salt 20 mg/mL, nicotine salt 40 mg/mL) using a refillable pod system and a standardized vaping protocol (one puff every 30 seconds, 10 puffs total). Serum nicotine concentrations and vital signs were assessed over 180 minutes; direct effects, craving, satisfaction, withdrawal, and respiratory symptoms were measured using questionnaires. CYP2A6 genotypes and the nicotine metabolite ratio were also assessed. RESULTS: Eleven (55%) participants were male and the median age was 23.5 years (range 18-67). All three formulations differed significantly in peak serum nicotine concentration (baseline adjusted Cmax, median (range): 12.0 ng/mL (1.6-27.3), 5.4 ng/mL (1.9-18.7), and 3.0 ng/mL (1.3-8.8) for nicotine salt 40 mg/mL, nicotine salt 20 mg/mL and free-base 20 mg/mL, respectively). All groups reached Cmax 2.0-2.5 minutes (median) after their last puff. Differences in subjective effects were not statistically significant. No serious adverse events were observed. CONCLUSIONS: Free-base 20 mg/mL formulations achieved lower blood nicotine concentrations than nicotine salt 20 mg/mL, while 40 mg/mL nicotine salt yielded concentrations similar to cigarette smoking. The findings can inform regulatory policy regarding e-liquids and their potential use in smoking cessation. IMPLICATIONS: Nicotine salt formulations inhaled by an e-cigarette led to higher nicotine delivery compared to nicotine-free-base formulations with the same nicotine concentration. These findings should be considered in future regulatory discussions. The 40 mg/mL nicotine salt formulation showed similar nicotine delivery as combustible cigarettes, albeit at concentrations over the maximum limit for e-liquids allowed in the European Union. Nicotine delivery resembling combustible cigarettes might be beneficial for smokers willing to quit to adequately alleviate withdrawal symptoms. However, increased nicotine delivery can also pose a public health risk, raising concerns about abuse liability, especially among youth and nonsmokers.

Effects of Hypericum perforatum (St John's wort) on the pharmacokinetics and pharmacodynamics of rivaroxaban in humans.

AIMS: To investigate the influence of a cytochrome P450 CYP3A4 and efflux transporter P-glycoprotein (P-gp) inducing Hypericum perforatum extract on the pharmacokinetics and pharmacodynamics of rivaroxaban. METHODS: Open-label, nonrandomized, sequential treatment interaction study. Following CYP3A4 and P-gp phenotyping using low-dose midazolam and fexofenadine, 12 healthy volunteers received a single oral dose of 20 mg rivaroxaban and rivaroxaban plasma concentrations and inhibition of the activated coagulation factor X (factor Xa) activity were measured prior to and up to 48 h postdosing. The procedures were repeated after 2 weeks' treatment with the H. perforatum extract. RESULTS: The geometric mean ratios for the area under the concentration-time curve and Cmax of rivaroxaban after/before induction with the H. perforatum extract were 0.76 (90% confidence interval [CI] 0.70, 0.82) and 0.86 (90% CI 0.76, 0.97), respectively. Inhibition of factor Xa activity was reduced with a geometric mean area under the effect-time curve ratio after/before induction of 0.80 (90% CI 0.71, 0.89). No clinically significant differences were found regarding Tmax (median 1.5 vs 1 h, P = .26) and terminal elimination half-life (mean 10.6 vs 10.8 h, P = .93) of rivaroxaban. The H. perforatum extract significantly induced CYP3A4 and P-gp activity, as evidenced by phenotyping. CONCLUSION: The CYP3A4/P-gp inducing H. perforatum extract caused a decrease of rivaroxaban exposure with a proportional decrease of the pharmacodynamic effect. Although the data do not justify a contraindication for the combination or a systematic adjustment of rivaroxaban dosage, avoidance of the combination or laboratory monitoring should be considered in patients taking hyperforin-containing H. perforatum extracts with rivaroxaban.

Prevalence of drug-drug interactions in older people before and after hospital admission: analysis from the OPERAM trial.

BACKGROUND: Drug-drug interactions (DDIs) are highly prevalent in older patients but little is known about prevalence of DDIs over time. Our main objective was to assess changes in the prevalence and characteristics of drug-drug interactions (DDIs) during a one-year period after hospital admission in older people, and associated risk factors. METHODS: We conducted a sub-study of the European OPERAM trial (OPtimising thERapy to prevent Avoidable hospital admissions in Multimorbid older people), which assessed the effects of a structured medication review (experimental arm) compared to usual care (control arm) on reducing drug-related hospital readmissions. All OPERAM patients (≥70 years, with multimorbidity and polypharmacy, hospitalized in four centers in Bern, Brussels, Cork and Utrecht between December 2016 and October 2018, followed over 1 year) who were alive at hospital discharge and had full medication data during the index hospitalization (at baseline i.e., enrolment at admission, and at discharge) were included. DDIs were assessed using an international consensus list of potentially clinically significant DDIs in older people. The point-prevalence of DDIs was evaluated at baseline, discharge, and at 2, 6 and 12 months after hospitalization. Logistic regression models were performed to assess independent variables associated with changes in DDIs 2 months after baseline. RESULTS: Of the 1950 patients (median age 79 years) included, 1045 (54%) had at least one potentially clinically significant DDI at baseline; point-prevalence rates were 58, 57, 56 and 57% at discharge, and 2, 6 and 12 months, respectively. The prevalence increased significantly from baseline to discharge (P < .001 [significant only in the control group]), then remained stable over time (P for trend .31). The five most common DDIs -all pharmacodynamic in nature- accounted for 80% of all DDIs and involved drugs that affect potassium concentrations, centrally-acting drugs and antithrombotics. At 2 months, DDIs had increased in 459 (27%) patients and decreased in 331 (19%). The main factor predictive of a change in the prevalence of DDIs was hyperpolypharmacy (≥10 medications). CONCLUSIONS: DDIs were very common; their prevalence increased during hospitalization and tended to remain stable thereafter. Medication review may help control this increase and minimize the risk of adverse drug events.

Pharmacokinetics and phenotyping properties of the Basel phenotyping cocktail combination capsule in healthy male adults.

AIMS: We compared the phenotyping metrics of a combination capsule formulation to its individual components of the newly composed Basel phenotyping cocktail. Moreover, we investigated a reduced sampling regimen for clinical applications. METHODS: We performed in vitro experiments and a crossover pharmacokinetic study in twelve healthy male subjects to compare the Basel phenotyping cocktail capsule containing 6 cytochrome P450 (CYP) probe drugs with individual administration of the same drugs. Parent compounds and selected metabolites were determined by liquid chromatography-tandem mass spectrometry. Metabolic ratios (MR) for are under the curve (AUC) and single time point measurements and their correlation were determined. RESULTS: Experiments with human liver microsomes and primary human hepatocytes in 3D co-culture confirmed that flurbiprofen is a suitable CYP2C9 substrate. Both cocktail formulations (capsule and individual probe drug administration) were well-tolerated and yielded reproducible MRs, which were almost identical. Correlations between single time point ratios and the corresponding AUC ratios depended on the sampling time point and the concentration time curve of the probe drugs. The MR of the capsule (Spearman rank correlation coefficient, Rs : 0.77-0.97) as well as the individual components (Rs : 0.69-0.99) correlated best at 6 h post-treatment considering all 6 CYPs. Moreover, the 2-h time points of the capsule agreed suitably with the AUC; however, the MR of omeprazole could not be determined for 10 out of 12 subjects. CONCLUSION: The capsule is easy to swallow, well tolerated and provides reliable estimates for CYP activity. The optimal sampling point for the capsule formulation is 6 h after intake.

Pharmacokinetics of oxycodone/naloxone and its metabolites in patients with end-stage renal disease during and between haemodialysis sessions.

BACKGROUND: The pharmacokinetics of oxycodone in patients with end-stage renal disease (ESRD) requiring haemodialysis are largely unknown. Therefore, we investigated the pharmacokinetics of oxycodone/naloxone prolonged release and their metabolites in patients with ESRD during and between haemodialysis sessions. METHODS: Single doses of oxycodone/naloxone (5/2.5 or 10/5 mg) were administered in nine patients with ESRD using a cross-over design on the day of dialysis and on a day between dialysis sessions. Plasma, dialysate and urine concentrations of oxycodone, naloxone and their metabolites were determined up to 48 h post-dosing using a liquid chromatography-tandem mass spectrometry system. RESULTS: Haemodialysis performed 6-10 h after dosing removed ∼10% of the administered dose of oxycodone predominantly as unconjugated oxycodone and noroxycodone or conjugated oxymorphone and noroxymorphone. The haemodialysis clearance of oxycodone based on its recovery in dialysate was (mean ± SD) 8.4 ± 2.1 L/h. The geometric mean (coefficient of variation) plasma elimination half-life of oxycodone during the 4-h haemodialysis period was 3.9 h (39%) which was significantly shorter than the 5.7 h (22%) without haemodialysis. Plasma levels of the active metabolite oxymorphone in its unconjugated form were very low. CONCLUSIONS: Oxycodone is removed during haemodialysis. The pharmacokinetics including the relatively short half-life of oxycodone in patients with ESRD with or without haemodialysis and the absence of unconjugated active metabolites indicate that oxycodone can be used at usual doses in patients requiring dialysis.

Dose evaluation of intravenous metamizole (dipyrone) in infants and children: a prospective population pharmacokinetic study.

PURPOSE: The prodrug metamizole is prescribed intravenously for postoperative pain in children, including off-label use in infants < 1 year. We aimed to assess the pharmacokinetics of the main metabolites of metamizole in children aged 3-72 months. METHODS: A single dose of 10 mg/kg metamizole was administered intravenously for postoperative analgesia. Pharmacokinetic samples were drawn at predefined time points. Pharmacokinetics of the main active metabolite 4-methylaminoantipyrine and three other metabolites was characterized by both non-compartmental and population pharmacokinetic analysis. AUC0-inf of 4-methylaminoantipyrine was calculated by non-compartmental analysis for two age cohorts (3-23 months, 2-6 years) and compared with the 80-125% range of adult dose-adjusted reference exposure (AUCref). Population pharmacokinetic analysis investigated age and weight dependency of the pharmacokinetics and optimal dosing strategies to achieve equivalent adult exposure. RESULTS: A total of 25 children aged 5 months-5.8 years (7.8-24.8 kg) with at least one concentration sample were included; 19 children had ≥ 5 predefined samples up to 10 h after metamizole dose administration. AUC0-inf of 4-methylaminoantipyrine in children 2-6 years was 29.9 mg/L/h (95% CI 23.4-38.2), significantly lower than AUCref (80-125% range 39.2-61.2 mg/L/h). AUC0-inf of 4-methylaminoantipyrine in infants < 2 years was 43.6 mg/L/h (95% CI 15.8-119.0), comparable with AUCref, while infants < 12 months showed increased exposure. Observed variability could be partially explained by covariates weight and age. CONCLUSIONS: Age-related changes in pharmacokinetics of 4-methylaminoantipyrine requires reduced weight-based IV dosing in infants < 1 year compared with infants and children up to 6 years (5 versus 10-20 mg/kg) to achieve equivalent adult exposure. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02660177 .

Using dried blood spots to facilitate therapeutic drug monitoring of antiretroviral drugs in resource-poor regions.

Objectives: We evaluated whether dried blood spots (DBS) are suitable to monitor combined ART when samples are collected in rural Tanzania and transported over a long distance to a specialized bioanalytical laboratory. Methods: Plasma and DBS samples were collected in Tanzania from study patients treated with nevirapine, efavirenz or lopinavir. In addition, plasma, whole blood and DBS samples were obtained from a cohort of HIV patients at the site of the bioanalytical laboratory in Switzerland. DBS samples were analysed using a fully automated LC-MS/MS method. Results: Comparison of DBS versus plasma concentrations of samples obtained from the bridging study in Switzerland indicated an acceptable bias only for nevirapine (18.4%), whereas for efavirenz and lopinavir a pronounced difference of -47.4% and -48.1% was found, respectively. Adjusting the DBS concentrations by the haematocrit and the fraction of drug bound to plasma proteins removed this bias [efavirenz +9.4% (-6.9% to +25.7%), lopinavir +2.2% (-20.0% to +24.2%)]. Storage and transportation of samples from Tanzania to Switzerland did not affect the good agreement between plasma and DBS for nevirapine [-2.9% (-34.7% to +29.0%)] and efavirenz [-9.6% (-42.9% to +23.8%)]. For lopinavir, however, adjusted DBS concentrations remained considerably below [-32.8% (-70.4% to +4.8%)] corresponding plasma concentrations due to decay of lopinavir in DBS obtained under field conditions. Conclusions: Our field study shows that the DBS technique is a suitable tool for therapeutic drug monitoring in resource-poor regions; however, sample stability remains an issue for certain analytes and therefore needs special consideration.

C-Reactive Protein and Procalcitonin in Case Reports of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) Syndrome.

BACKGROUND: The spectrum of inflammatory marker response in DRESS (drug reaction with eosinophilia and systemic symptoms) syndrome has not been systematically characterized. METHODS: An epidemiological biomarker study of C-reactive protein (CRP) and procalcitonin (PCT) values in patients with DRESS syndrome reported at 2 regional pharmacovigilance centers in Switzerland or published in the medical literature 2008-2016 was performed. RESULTS: Ninety-four DRESS cases were studied. All cases showed a CRP value > 10 mg/L (the upper limit of normal). The mean CRP value was 109.2 ± 79.4 mg/L. CRP values were significantly higher in 22 cases where a cause of inflammation besides DRESS could not be excluded (mean 162.1 vs. 92.9 mg/L; p = 0.003). Receiver operator characteristics curve analysis showed a moderate performance with a CRP cut-off value of 99.4 mg/L (AUC 0.717) to distinguish between patients with and without a possible additional cause of inflammation. The mean and median PCT values were 2.44 ± 5.94 and 0.69 ng/mL, respectively (n = 25 patients). Patients in whom an additional cause of inflammation besides DRESS could not be excluded showed a median PCT of 1.37 ng/mL (n = 9) versus 0.67 ng/mL (n = 16) in patients with DRESS only. PCT values were above the normal cut-off of 0.1 ng/mL, suggestive of bacterial infection in all but 1 case. Furthermore, there was a correlation between PCT values and hepatic enzyme measurements. CONCLUSIONS: Evaluating CRP and PCT values might be of use in helping physicians to distinguish between cases of DRESS syndrome with and without concurrent infection or other causes of inflammation. Further prospective investigation is required to define the use of these inflammatory markers in the management of DRESS.

Ticagrelor induced systemic inflammatory response syndrome.

BACKGROUND: Ticagrelor is a reversible and direct-acting oral antagonist of the adenosine diphosphate receptor P2Y12. Possible adenosine-mediated effects of ticagrelor on inflammation are complex and incompletely understood. To our knowledge, ticagrelor-induced systemic inflammatory response syndrome (SIRS) has not yet been described. CASE PRESENTATION: We report the case of an 84 years old patient presenting with SIRS subsequent to initiation of ticagrelor after implantation of two drug eluting stents. A broad diagnostic work-up for alternative causes and therapeutic measures were unrevealing. Discontinuation of the agent was followed by rapid improvement in clinical and laboratory signs of SIRS. CONCLUSIONS: After exclusion of other causes, ticagrelor needs to be considered as a possible causative agent for SIRS. Due to the widespread use of ticagrelor, clinicians should be aware of this possible adverse drug reaction.

Reduction of hyperbilirubinemia with hypericum extract (St. John's Wort) in a patient with Crigler-Najjar syndrome type II.

AIMS: Crigler-Najjar syndrome (CN) type II is a congenital disease with unconjugated hyperbilirubinemia due to a deficiency of uridine 5'-diphospho-glucuronosyltransferase 1A1. Since the currently proposed treatment with phenobarbital is associated with adverse reactions, we investigated the effect of hypericum extract. METHODS: Repetitive determination of total serum bilirubin in a female with CN type II before, during and after daily treatment with 900 mg hypericum extract on two occasions for 8 weeks. Confirmation of the enzyme-inducing effect of hypericum using the cytochrome P450 3A4 probe drug i.v. midazolam. RESULTS: Hypericum reduced midazolam exposure by 42% and the total serum bilirubin concentration by 30 to 35%. CONCLUSIONS: Hypericum extract is a potential alternative to phenobarbital in patients with CN type II.

Pharmacokinetics and Concentration-Effect Relationship of Oral LSD in Humans.

BACKGROUND: The pharmacokinetics of oral lysergic acid diethylamide are unknown despite its common recreational use and renewed interest in its use in psychiatric research and practice. METHODS: We characterized the pharmacokinetic profile, pharmacokinetic-pharmacodynamic relationship, and urine recovery of lysergic acid diethylamide and its main metabolite after administration of a single oral dose of lysergic acid diethylamide (200 µg) in 8 male and 8 female healthy subjects. RESULTS: Plasma lysergic acid diethylamide concentrations were quantifiable (>0.1 ng/mL) in all the subjects up to 12 hours after administration. Maximal concentrations of lysergic acid diethylamide (mean±SD: 4.5±1.4 ng/mL) were reached (median, range) 1.5 (0.5-4) hours after administration. Concentrations then decreased following first-order kinetics with a half-life of 3.6±0.9 hours up to 12 hours and slower elimination thereafter with a terminal half-life of 8.9±5.9 hours. One percent of the orally administered lysergic acid diethylamide was eliminated in urine as lysergic acid diethylamide, and 13% was eliminated as 2-oxo-3-hydroxy-lysergic acid diethylamide within 24 hours. No sex differences were observed in the pharmacokinetic profiles of lysergic acid diethylamide. The acute subjective and sympathomimetic responses to lysergic acid diethylamide lasted up to 12 hours and were closely associated with the concentrations in plasma over time and exhibited no acute tolerance. CONCLUSIONS: These first data on the pharmacokinetics and concentration-effect relationship of oral lysergic acid diethylamide are relevant for further clinical studies and serve as a reference for the assessment of intoxication with lysergic acid diethylamide.

Hematological safety of metamizole: retrospective analysis of WHO and Swiss spontaneous safety reports.

PURPOSE: Since the 1970s, the use of metamizole is controversial due to the risk of agranulocytosis. The aim of this study was to analyze individual case safety reports (ICSRs) of metamizole-associated hematological adverse drug reactions (ADRs). METHODS: International and Swiss metamizole-associated ICSR concerning selected hematological ADR were retrieved from VigiBase™, the World Health Organization Global Database of ICSR, and the Swiss Pharmacovigilance Database. We evaluated demographic data, co-medication, drug administration information, dose and duration of metamizole treatment, as well as the latency time of ADR, their course, and severity. The subgroup analysis of Swiss reports allowed us to analyze cases with fatal outcome more in depth and to estimate a rough minimal incidence rate. RESULTS: A total of 1417 international and 77 Swiss reports were analyzed. Around 52 % of the international and 33 % of the Swiss metamizole-associated hematological ADR occurred within a latency time of ≤7 days. More women were affected. The annual number of hematological reports and those with fatal outcome increased over the last years parallel to metamizole sales figures. In Switzerland, the minimal incidence rate of agranulocytosis was 0.46-1.63 cases per million person-days of use (2006-2012). Female sex, old age, pancytopenia, and co-medication with methotrexate were striking characteristics of the seven Swiss fatal cases. CONCLUSIONS: Metamizole-associated hematological ADR remain frequently reported. This is underscored by increasing annual reporting rates, which mainly reflect growing metamizole use. Early detection of myelotoxicity and avoidance of other myelotoxic substances such as methotrexate are important measures for preventing fatalities.

Clinical assessment of potential drug interactions of faldaprevir, a hepatitis C virus protease inhibitor, with darunavir/ritonavir, efavirenz, and tenofovir.

BACKGROUND: Faldaprevir is a potent, once-daily hepatitis C virus (HCV) NS3/4A protease inhibitor. Studies were performed to investigate potential drug interactions between faldaprevir and the commonly used antiretrovirals darunavir/ritonavir, efavirenz, and tenofovir to guide the coadministration of faldaprevir with these agents in human immunodeficiency virus/HCV-coinfected patients. METHODS: In 3 open-label, phase 1 pharmacokinetic (PK) studies, healthy adult volunteers received (1) darunavir/ritonavir (800 mg/100 mg once daily) with and without faldaprevir (240 mg once daily); (2) faldaprevir (240 mg twice daily) with and without efavirenz (600 mg once daily); or (3) faldaprevir (240 mg twice daily) or tenofovir (300 mg once daily) alone and in combination. To assess potential drug interactions, geometric mean ratios and 90% confidence intervals for PK parameters were calculated. Safety was evaluated. RESULTS: Efavirenz decreased faldaprevir area under the concentration-time curve (AUC) by 35%, Cmax by 28%, and Cmin by 46%, consistent with induction of CYP3A by efavirenz. Tenofovir decreased faldaprevir AUC by 22%, which was not considered to be clinically relevant. Faldaprevir had no clinically relevant effects on darunavir or tenofovir PK (15% and 22% AUC increase, respectively). Adverse events were consistent with the known safety profiles of faldaprevir and the antiretrovirals being examined. CONCLUSIONS: No clinically significant interactions were observed between faldaprevir and darunavir/ritonavir or tenofovir. A potentially clinically relevant decrease in faldaprevir exposure was observed when coadministered with efavirenz; this decrease can be managed using the higher of the 2 faldaprevir doses tested in phase 3 trials (240 mg once daily as opposed to 120 mg once daily).

Therapeutic drug monitoring of once daily aminoglycoside dosing: comparison of two methods and investigation of the optimal blood sampling strategy.

PURPOSE: Therapeutic drug monitoring of patients receiving once daily aminoglycoside therapy can be performed using pharmacokinetic (PK) formulas or Bayesian calculations. While these methods produced comparable results, their performance has never been checked against full PK profiles. We performed a PK study in order to compare both methods and to determine the best time-points to estimate AUC0-24 and peak concentrations (C max). METHODS: We obtained full PK profiles in 14 patients receiving a once daily aminoglycoside therapy. PK parameters were calculated with PKSolver using non-compartmental methods. The calculated PK parameters were then compared with parameters estimated using an algorithm based on two serum concentrations (two-point method) or the software TCIWorks (Bayesian method). RESULTS: For tobramycin and gentamicin, AUC0-24 and C max could be reliably estimated using a first serum concentration obtained at 1 h and a second one between 8 and 10 h after start of the infusion. The two-point and the Bayesian method produced similar results. For amikacin, AUC0-24 could reliably be estimated by both methods. C max was underestimated by 10-20% by the two-point method and by up to 30% with a large variation by the Bayesian method. CONCLUSIONS: The ideal time-points for therapeutic drug monitoring of once daily administered aminoglycosides are 1 h after start of a 30-min infusion for the first time-point and 8-10 h after start of the infusion for the second time-point. Duration of the infusion and accurate registration of the time-points of blood drawing are essential for obtaining precise predictions.

[Drugs and diarrhea]. / Arzneistoffe und Diarrhoe.

Drug induced diarrhea is a frequent adverse event. The pathophysiological mechanisms include intraluminal accumulation of osmotically active substances, increased secretion or impaired resorption of gastrointestinal fluids, stimulation of gastrointestinal motility, or inflammation of gastrointestinal mucosa. For many drugs, however, the causative mechanism is unknown. A careful drug history, including non-prescription drugs and additives that frequently cause diarrhea, is essential for the identification of potential causative substances. The clinical course of drug-induced diarrhea in many cases is mild and self-limited. In severe cases fluid-and electrolyte substitution, symptomatic and in certain cases specific therapy can be necessary. Symptomatic treatment primarily includes opioids and intraluminal adsorbents. In special cases octreotide or scopolamine can be used.

Residents' Knowledge regarding Recreational Drug Screening Immunoassays at a Swiss Hospital Group.

Introduction: In case of suspected acute recreational drug toxicity, immunoassays are commonly used as diagnostic tools. Although easy to handle, understanding of their limitations is necessary for a correct interpretation of the results. The aim of this project was to investigate residents' knowledge regarding drug screening immunoassays at a Swiss hospital group. Methods: All residents of a large hospital group in Switzerland were invited by e-mail to participate in an anonymous survey. Following ten multiple choice questions on drug screening tests, the participants were also asked about their demographics, whether they used drug screening tests on a regular basis, and how confident they felt in their ability to interpret test results. Results: The ten knowledge questions were answered by 110 of the 1026 residents (11%). Among the 108 participants with available demographics, 90% were 25-35 years old, 63% were female, and 70% were at least in their 4th year of residency. The median score of correct answers was 4 out of 10 (range 0-7) and in 50% of the questions, the correct answer was the most frequently selected response. No significant differences in the knowledge scores were found based on the training, confidence level, or the frequency of drug tests used in daily work. Conclusion: This survey revealed widespread knowledge gaps among residents regarding the interpretation of immunoassay-based drug test results. These findings can be used to implement educational measures on this topic and might provide a basis for targeted information on common pitfalls to be included in laboratory reports.

Use of metamizole and other non-opioid analgesics in Switzerland between 2014 and 2019: an observational study using a large health insurance claims database.

OBJECTIVE: To investigate claims patterns for metamizole and other non-opioid analgesics in Switzerland. To characterise users of these non-opioid analgesics regarding sex, age, comedications and canton of residence. METHODS: We conducted a retrospective descriptive study using administrative claims data of outpatient prescribed non-opioid analgesics of the Swiss health insurance company Helsana between January 2014 and December 2019. First, we evaluated the number of claims and defined daily doses  per year of metamizole, ibuprofen, diclofenac and paracetamol in adults aged 18 years or over. Second, we characterised new users of these non-opioid analgesics in terms of sex, age, claimed comedications and canton of residence. RESULTS: From 2014 to 2019, among the investigated non-opioid analgesics, metamizole showed the highest increase in claims (+9545 claims, +50%) and defined daily doses (+86,869 defined daily doses, +84%) per 100,000 adults. Metamizole users had the highest median age (62 years [IQR: 44-77]) compared to ibuprofen (47 years [IQR: 33-62]), diclofenac (57 years [IQR: 43-71]) and paracetamol (58 years [IQR: 39-75]) users. Metamizole users also more frequently claimed proton pump inhibitors, anticoagulants, platelet aggregation inhibitors and antihypertensive drugs than users of other non-opioid analgesics. While metamizole was most frequently claimed in German-speaking regions of Switzerland, ibuprofen and paracetamol were most frequently claimed in the French-speaking regions and diclofenac in German- and Italian-speaking regions. CONCLUSION: In Switzerland, metamizole was increasingly claimed between 2014 and 2019. Metamizole was most frequently claimed by older adults and patients with comedications suggestive of underlying conditions, which can be worsened or caused by use of nonsteroidal anti-inflammatory drugs. The lack of studies regarding the effectiveness and safety of metamizole in this population warrants further investigation.

Developing indicators for medication-related readmissions based on a Delphi consensus study.

BACKGROUND: Medication-related readmissions challenge healthcare systems by burdening patients, increasing costs and straining resources. However, to date, there has been no consensus study on indicators for medication-related readmissions. OBJECTIVES: This Delphi study aimed to develop a consensus-based set of indicators for detecting patients at risk of medication-related readmission. METHODS: An expert panel of clinical pharmacists, physicians and nursing experts participated in a two-round Delphi study. In round 1, 31 indicators taken from the literature were rated for relevance on a scale from 1 to 9, with a median rating of 7 or higher suggesting relevance. The RAND/UCLA method was used to determine consensus. In round 2, indicators lacking consensus were re-rated together with a series of new indicators generated by the experts. Additional details were sought for some indicators. The main outcomes were the relevance of, consensus on, and completeness of the proposed indicators for identifying risks of 30-day medication-related readmission. RESULTS: Thirty-eight experts participated in round 1. Consensus was found for all the indicators, with 25 included and 6 excluded. Thirty-four experts participated in round 2. Consensus was found for all 5 newly suggested indicators, and 4 were included. The expert panel prioritized the following indicators: (1) insufficient communication between different healthcare providers, (2) polypharmacy (≥7 medications), (3) low rates of medication adherence (twice-weekly mistakes or missing administration), (4) complex medication regimens (≥3 doses, ≥2 dosage forms and ≥2 administration routes per day), and (5) multimorbidity (≥3 chronic conditions). The final set comprised 29 indicators. CONCLUSIONS: The indicator set developed for flagging potential medication-related readmissions could guide priorities for clinical pharmacy services at hospital discharge, improving patient outcomes and resource use. A validation study of these indicators is planned.

Pharmacokinetics-Based Pediatric Dose Evaluation and Optimization Using Saliva - A Case Study.

Understanding pharmacokinetics (PK) in children is a prerequisite to determine optimal pediatric dosing. As plasma sampling in children is challenging, alternative PK sampling strategies are needed. In this case study we evaluated the suitability of saliva as alternative PK matrix to simplify studies in infants, investigating metamizole, an analgesic used off-label in infants. Six plasma and 6 saliva PK sample collections were scheduled after a single intravenous dose of 10 mg/kg metamizole. Plasma/saliva pharmacometric (PMX) modeling of the active metabolites 4-methylaminoantipyrine (4-MAA) and 4-aminoantipyrine (4-AA) was performed. Various reduced plasma sampling scenarios were evaluated by PMX simulations. Saliva and plasma samples from 25 children were included (age range, 5-70 months; weight range, 8.7-24.8 kg). Distribution of metamizole metabolites between plasma and saliva was without delay. Estimated mean (individual range) saliva/plasma fractions of 4-MAA and 4-AA were 0.32 (0.05-0.57) and 0.57 (0.25-0.70), respectively. Residual variability of 4-MAA (4-AA) in saliva was 47% (28%) versus 17% (11%) in plasma. A simplified sampling scenario with up to 6 saliva samples combined with 1 plasma sample was associated with similar PK parameter estimates as the full plasma sampling scenario. This case study with metamizole shows increased PK variability in saliva compared to plasma, compromising its suitability as single matrix for PK studies in infants. Nonetheless, rich saliva sampling can reduce the number of plasma samples required for PK characterization, thereby facilitating the conduct of PK studies to optimize dosing in pediatric patients.