OBJECTIVE: Several drug-drug interaction (DDI) checkers such as DDI-Predictor have been developed to detect and grade DDIs. DDI-Predictor gives an estimate of the magnitude of an interaction based on the ratio of areas under the curve. The objective of the present study was to analyse the frequencies of DDIs involving well-known strong interactors such as rifampicin and selective serotonin reuptake inhibitors (SSRIs), as reported by a clinical pharmacy team using DDI-Predictor, and the pharmacist intervention acceptance rate.
METHODS: The pharmacist intervention rate and the physician acceptance rate were calculated for DDIs involving rifampicin or the SSRIs fluoxetine, paroxetine, duloxetine and sertraline. The rates were compared with a bilateral χ2 test or Fisher\'s exact test.
RESULTS: Of the 284 DDIs recorded, 38 (13.4%) involved rifampicin and 78 (27.5%) involved SSRIs. The pharmacist intervention rate differed significantly (68.4% for rifampicin vs 48.8% for SSRIs; p=0.045) but the physician acceptance rate did not (84.6% for rifampicin vs 81.6% for SSRIs; p=1). Pharmaceutical interventions for SSRIs were more frequent when the ratio of the area under the drug concentration versus time curve in DDI-Predictor was >2. Pharmacists were more likely to issue a pharmacist intervention for DDIs involving rifampicin because of a high perceived risk of treatment failure and were less likely to issue a pharmacist intervention for DDIs involving an SSRI, except when the suspected interaction was strong.
CONCLUSIONS: DDI checkers can help pharmacists to manage DDIs involving strong interactors. DDIs involving strong inhibitors versus a strong inducer differ with regard to their intervention and acceptance rates, notably due to the estimation of the magnitude of the DDI.

The mTOR-inhibitor everolimus is a precision drug with antiepileptogenic properties approved for treatment of epilepsy in persons with tuberous sclerosis complex (TSC) in combination with other antiseizure medications (ASMs). However, the pharmacokinetic variability of everolimus is scarcely described, and the available information on pharmacokinetic interactions is scarce. The purpose of this study was to investigate pharmacokinetic variability of everolimus in patients with TSC, and the impact of age, sex and comedication. In this retrospective observational study we used anonymized data from medical records of patients with TSC using everolimus in Norway and Denmark, 2012 to 2020. Long-term therapeutic drug monitoring (TDM) identified inter-patient and intra-patient variability. The study included 59 patients, (36 females (61%)), median age 22 (range 3-59 years). Polytherapy was used in 50 patients (85%). The most frequently used ASMs were lamotrigine (n = 21), valproate (n = 17), and levetiracetam (n = 13). Blood concentrations of everolimus were measured in all patients. Pharmacokinetic variability of everolimus between patients was extensive, as demonstrated by a 24-fold variability from minimum-maximum concentration/dose (C/D)-ratios. The coefficient of variation (CV) for intra-patient (n = 59) and inter-patient variability (n = 47, ≥3 measurements) was 40% and 43%, respectively. The C/D-ratio of everolimus was 50% lower in 13 patients (22%) using enzyme-inducing ASMs compared to the 30 patients who did not (0.7 vs 1.4 ng/mL mg, P < .05). Age and sex were not significantly associated with changes in C/D-ratios of everolimus. Long-term TDM identified extensive variability in concentrations over time for everolimus both within and between patients, where comedication with enzyme-inducing ASMs was an important contributing factor. The findings suggest a need for TDM in patients with TSC treated with everolimus.

BACKGROUND: Concentrations of metoprolol in exhaled breath condensate (EBC) have not been investigated. Herein, we aim to determine the metoprolol levels in EBC, plasma, and urine samples.
METHODS: Biological samples were collected from 39 patients receiving metoprolol. Metoprolol was determined using liquid chromatography mass spectrometery. The obtained metoprolol levels in biological fluids were investigated for possible inter-correlations.
RESULTS: Acceptable linearity was obtained with coefficient of determinations equal to 0.9998, 0.9941, and 0.9963 for EBC, plasma, and urine samples, respectively. The calibration curves were linear in the ranges of 0.6-500, 0.4-500, and 0.7-10,000 µg·L- 1 regarding EBC, plasma, and urine samples, respectively. The detection and quantification limits were (0.18, 0.12, and 0.21 µg·L- 1) and (0.60, 0.40, and 0.70 µg·L- 1) for EBC, plasma, and urine samples, respectively. The relative standard deviations for the intra- and inter-day replications were obtained between 5.2 and 6.1 and 3.3-4.6%, respectively. The obtained mean metoprolol levels in EBC, plasma, and urine samples of 39 patients were 5.35, 70.76, and 1943.1 µg·L- 1. There were correlations between daily dose and plasma and urinary concentrations of metoprolol in the investigated samples, whereas no significant correlation was observed for daily dose and EBC levels. The correlation among plasma-urine levels was significant, however, the non-significant correlation was obtained between plasma and EBC concentrations.
CONCLUSIONS: Metoprolol levels varied widely due to the metabolic pattern of the Azeri population, different dosages received by the patients, formulation effects, age, sex, and interactions with the co-administered drugs. A poor correlation of EBC-plasma concentrations and a significant correlation of plasma-urine concentrations were observed. Further investigations are required to provide the updated services to personalized medicine departments.

The thiopurine drugs-azathioprine and mercaptopurine-are purine antimetabolites used for the treatment of autoimmune hepatitis. These drugs undergo metabolism through genetically determined pathways, which influences their effectiveness and toxicity. There is scarce information regarding the clinical effects of measuring drug metabolites in these patients. The goal of the study is to test the clinical significance of measuring thiopurine metabolites in patients unsuccessfully treated with thiopurines. Clinical and laboratory data collected for patients who were treated for autoimmune hepatitis between 2015 and 2018, and did not achieve full remission under thiopurine therapy and had thiopurine metabolite levels measured due to lack of response and suspicious side effects were chosen. We compared clinical and laboratory data before and after the therapy change. The study included 25 tests of thiopurine metabolites in 21 patients. Six tests had therapeutic levels. Three tests showed high levels leading to lowering the drug dose. In 11 cases, levels of 6-thioguanine nucleotide were low; the dose was not changed in 3 of these, and the dose was increased in the remaining 8. Shunting was observed in 5 cases, 2 of which were mild and the dose was not changed. In the remaining 3, the dose was decreased, and allopurinol was added. Significant improvements in liver enzymes were observed following dose adjustments. We showed that, in cases of suboptimal response to thiopurine treatment, measuring thiopurine metabolites had an important role in optimizing therapy. In most patients, changing the dose led to a significant improvement with no need to switch to secondline therapies.

UNASSIGNED: Providing data on the superior efficacy of vancomycin administered based on the area under the curve over 24 hours to the minimum inhibitory concentration of vancomycin (AUC24/MIC) is crucial. However, data on dosing and monitoring of vancomycin pharmacokinetics in the pediatric population are limited. Previous findings have showed that intermittent infusion of vancomycin (IIV) may not achieve the desired levels, continous infusions of vancomycin (CIV) reach the desired serum concentration faster than IIV and are associated with reduced nephrotoxicity.
UNASSIGNED: This study aimed to compare the serum concentrations, AUC24, clinical variables, and adverse effects of two vancomycin administration methods in the pediatric population.
UNASSIGNED: This study was a double-blind, randomized, controlled clinical trial conducted at a tertiary children\'s teaching hospital. Inclusion criteria were age between 2 months and 15 years and weight less than 67 kilograms, with exclusion criteria including renal impairment. Participants were divided into CIV and IIV groups following distinct administration protocols. Demographic, clinical, and laboratory data, including vancomycin serum concentrations, were compiled. Assessments included pediatric mortality risk, pediatric sequential organ failure assessment, and regular temperature monitoring. Pharmacokinetic analysis was conducted using Monolix software 2023R1. Primary endpoints were vancomycin serum levels and AUC24 between cohorts on day three, with nephrotoxicity and additional adverse drug responses evaluated.
UNASSIGNED: Sixty-eight patients in the pediatric intensive care unit (PICU) were allocated to either CIV (33) or IIV (35) for vancomycin treatment. In the CIV group, 82% of patients achieved an AUC24 ≥ 400 mg.h/L, compared to 23% in the IIV group. Continuous infusions of vancomycin demonstrated a greater AUC24 (587.7 ± 184.4 mg.h/L vs. 361.9 ± 113.2 mg.h/L, P < 0.05) compared to IIV. Two cases of nephrotoxicity were reported, one in each group, with mortality and adverse events being comparable between the two groups.
UNASSIGNED: This study demonstrated that continuous vancomycin infusion has a higher success rate in safely achieving therapeutic vancomycin levels in PICU patients compared to intermittent vancomycin infusion.

Tuberculosis (TB) continues to pose a significant health challenge worldwide, emphasizing the importance of prompt diagnosis and efficient monitoring of treatment outcomes for effective disease control. Biomarkers have become increasingly important in the realm of TB diagnoses and treatment. The objective of this comprehensive review is to examine the present state of biomarkers employed in the diagnosis of TB, monitoring the response to treatment, and predicting treatment outcomes. In this study, we undertake a comprehensive examination of the diverse biomarkers utilized in TB diagnoses, spanning molecular, immunological, and other novel methodologies. Furthermore, we examine the potential of biomarkers in the context of therapeutic monitoring, assessment of treatment effectiveness, and anticipation of drug resistance. Additionally, this paper presents future prospects regarding the utilization of biomarkers in the therapy of tuberculosis.

In this study, plasma belimumab concentrations were measured over the course of treatment in systemic lupus erythematosus (SLE) patients on belimumab therapy, and intra- and interindividual variations in plasma belimumab concentration were evaluated. A single-center prospective study was conducted at Oita University Hospital to evaluate trough plasma concentrations over the course of treatment in 13 SLE patients treated with intravenous belimumab. Plasma belimumab concentrations were measured by a validated ultra-high performance liquid chromatography with tandem mass spectrometry method. The median age of the patients was 40 (interquartile range: 35-51) years and the median weight was 51.8 (47.0-58.1) kg. A mean of 9.4 (range: 1-13) blood samples was collected per patient at routine visits. The mean (± SD) plasma belimumab concentration was 33.4 ± 11.9 μg/mL in the patient with the lowest concentration and 170.0 ± 16.6 μg/mL in the patient with the highest concentration, indicating a 5-fold difference between patients. On the other hand, the within-patient coefficient of variation ranged from 7.1% to 35.7%, showing no large variations. No significant correlation was observed between plasma belimumab concentration and belimumab dose (mg/kg) (Spearman\'s rank correlation coefficient = 0.22, p = .54). Examinations of trough plasma belimumab concentrations over the course of treatment in patients with SLE showed small intraindividual variation but large interindividual variation. Plasma belimumab trough concentration varied widely among patients administered the approved dose.

The optimal frequency and timing of laboratory monitoring during isotretinoin treatment remains controversial. We aimed to investigate the frequency, timing, and severity of abnormal results during isotretinoin for acne. We conducted a retrospective cohort study comprising 444 acne patients prescribed isotretinoin at Boston Medical Center from 2004 to 2017; these patients had at least one available baseline laboratory result. We categorized patients into two groups: group A (normal values at baseline and during the first 2 months of isotretinoin therapy) and group B (abnormal values at baseline or during the first 2 months of isotretinoin therapy) and assessed the laboratory values after 2 months. The frequency of abnormal results for triglycerides, cholesterol, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) after 2 months for patients in group A was 21.1%, 13.6%, 8.8%, and 6.0%, respectively, with very rare grade 2 (moderate) or higher abnormalities. In contrast, the frequency of abnormal results for patients in group B for triglycerides, cholesterol, AST, and ALT was higher at 67.9%, 88.0%, 40.0%, and 25.0%, respectively (P < 0.05, except for ALT). No patient developed higher than grade 1 (mild) complete blood count (CBC) abnormality. This study proposed that healthy patients with normal results at baseline and during the first 2 months of isotretinoin therapy might not need routine monitoring after month 2 of medication. Routine monitoring of CBC is not necessary.

Direct oral anticoagulants (DOACs) have significant advantages over vitamin K antagonists including lack of need for routine laboratory monitoring. However, assessment of DOAC effect and concentration may be important to guide clinical management including need for DOAC reversal, particularly in acute or emergent situations. In this manuscript, the authors describe tests to screen for DOAC presence and tests that have demonstrated equivalence to gold standard testing for quantifying DOAC exposure. They also discuss the effect of DOACs on other coagulation assays and strategies for monitoring unfractionated heparin in patients with concomitant DOAC exposure.

As the population continues to age, the occurrence of chronic illnesses and comorbidities that often necessitate the use of polypharmacy has been on the rise. Polypharmacy, among other factors that tend to coincide with chronic diseases, such as obesity, impaired kidney and liver function, and older age, can increase the risk of medication errors (MEs). Our study aims to evaluate the prevalence of MEs in the Internal medicine, Cardiology, and Neurology departments at the secondary-level university hospital. We conducted a prospective observational study of 145 patients\' electronic or paper-based data of inpatient prescriptions and patients\' pharmacokinetic risk factors, such as an impairment of renal and/or hepatic function, weight, and age. All included patients collectively received 1252 prescribed drugs. The median (Q1; Q3) number of drugs per patient was 8 (7;10). At least one ME was identified in 133 out of the 145 patients, indicating a significantly higher prevalence than hypothesized (91.7% vs. 50%; p < .001). There was moderate, positive correlation between the quantity of prescribed drugs and the number of MEs, meaning that the more drugs are prescribed, the higher the number of identified MEs (Spearman\'s ρ = 0.428; p < .001). These findings suggest that there is a need for continuous medication education activity for prescribing physicians, continuous evaluation of prescription appropriateness to objectively identify the MEs and to contribute to more rational patient treatment.