Advancements on the impact of hydroxychloroquine in systemic lupus erythematosus

Hydroxychloroquine (HCQ) has gained significant attention as a therapeutic option for systemic lupus erythematosus (SLE) because of its multifaceted mechanism of action. It is a lipophilic, lysosomotropic drug, that easily traverses cell membranes and accumulates in lysosomes. Once accumulated, HCQ alkalizes lysosomes within the cytoplasm, thereby disrupting their function and interfering with processes like antigen presentation. Additionally, HCQ has shown potential in modulating T-cell responses, inhibiting cytokine production, and influencing Toll-like receptor signaling. Its immunomodulatory effects have generated interest in its application for autoimmune disorders. Despite its established efficacy, uncertainties persist regarding the optimal therapeutic concentrations and their correlation with adverse effects such as retinal toxicity. Therefore, standardized dosing and monitoring guidelines are crucial. In this study, we provide a comprehensive review of the mechanisms, efficacy, dosing variations, and retinal toxicity profiles of HCQ, which are essential to optimize SLE treatment protocols and ensure patient safety.

Effect of hydroxychloroquine blood concentration on the efficacy and ocular toxicity of systemic lupus erythematosus

In the absence of evidence-based guidance on the impact of hydroxychloroquine (HCQ) blood concentration on efficacy and ocular toxicity in systemic lupus erythematosus (SLE), the clinical monitoring of HCQ blood concentration is not yet widely performed, which raised concerns about the necessity of conducting HCQ blood concentration monitoring. In this retrospective study, we consecutively enrolled 135 patients with SLE who received HCQ treatment for more than 6 months from July 2022 to December 2022. Ocular toxicity was evaluated by collecting relevant retinal parameters using optical coherence tomography angiography (OCTA). Therapeutic efficacy was evaluated using the SLE disease activity index (SLEDAI) and relevant clinical parameters. HCQ blood concentration was determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Spearman correlation analysis revealed that the cumulative dose of HCQ was positively correlated with the foveal avascular zone (FAZ) perimeter and FAZ area (r = 0.734, P < 0.001; r = 0.784, P < 0.001). Meanwhile, the treatment duration of HCQ was positively correlated with FAZ perimeter and FAZ area (r = 0.761, P < 0.001; r = 0.882, P < 0.001). The univariate and multivariate logistic regression analyses indicated that HCQ blood concentration was associated with the disease activity of patients with SLE (odds ratio 0.994, 95% CI 0.990-0.999). HCQ blood concentration may be an important factor in assessing the therapeutic effectiveness of SLE patients. The HCQ-related ocular toxicity was a long-term effect related to long term exposure, rather than the blood concentration of HCQ at the time of testing. More importantly, when addressing HCQ-related ocular toxicity, it may be crucial to pay attention to the cumulative dose and treatment duration of HCQ.

Prolonged efficacy of cefazolin in intraosseous regional prophylaxis for total knee arthroplasty: a rabbit model study

BACKGROUND

A novel approach known as intraosseous regional administration (IORA) has emerged as a technique for delivering prophylactic antibiotics, and it results in higher tissue concentrations around the knee. It is hypothesized that IORA of cefazolin for antibiotic prophylaxis during total knee arthroplasty will result in sustained effective levels for a longer duration. The aim of the current study was to investigate temporal changes in peri-knee cefazolin blood concentrations after IORA of cefazolin.

METHODS

Twelve rabbits were randomly divided into two groups, with six rabbits in each group. In control group a single intravenous bolus injection of cefazolin (10 mL, 100 mg) was administered into the marginal ear vein. In experimental groupexperimental group the same dose of cefazolin was injected into the left tibial marrow cavity after tourniquet inflation at the base of the left thigh. Blood samples were collected periodically at different timepoints, and cefazolin concentrations were determined.

RESULTS

The intraosseous treatment resulted in significant differences in plasma cefazolin concentrations at all timepoints. Experimental group exhibited higher plasma cefazolin concentrations than control group.

CONCLUSIONS

Cefazolin in intraosseous regional prophylaxis exhibits effectiveness in intraoperative antibiotic prophylaxis by maintaining concentrations above the minimum inhibitory concentration for extended durations, rather than relying solely on high concentrations.

Analysis of Factors Influencing Whole Blood Hydroxychloroquine Concentration in Patients with Systemic Lupus Erythematosus in China

INTRODUCTION

The aim of this study was to determine the factors associated with the concentrations of hydroxychloroquine (HCQ) and its major metabolite, desethylhydroxychloroquine (DHCQ), in patients with systemic lupus erythematosus (SLE).

METHODS

Patients with SLE taking oral HCQ for at least 3 months were recruited from the Department of Rheumatology and Immunology of Nanjing Drum Tower Hospital. Clinical characteristics and laboratory values were examined. The concentrations of HCQ and DHCQ were measured by high-performance liquid chromatography, and the effects of various factors on the concentrations were investigated.

RESULTS

A total of 272 patients were included in this study. The average concentration of HCQ was 690.90 ng/ml and the average concentration of DHCQ was 431.84 ng/ml. Multivariate analysis indicated that gender (P = 0.015), age (year) (P < 0.001), weight (kg) (P = 0.013), duration of HCQ use (month) (P < 0.001), systemic lupus erythematosus disease activity index (SLEDAI) (P < 0.001), platelet count (× 109/l) (P < 0.001), immunoglobulin G levels (g/l) (P = 0.014) were associated with low HCQ concentrations. Gender (P = 0.006), duration of HCQ use (month) (P < 0.001), SLEDAI (P = 0.007), and platelet count (× 109/l) (P < 0.001) were associated with low DHCQ concentrations.

CONCLUSIONS

Patients with SLE require long-term administration of HCQ, but blood levels vary widely between individuals. Studying the factors influencing the blood HCQ and DHCQ concentrations and optimizing the dose according to individual characteristics might help to improve the efficacy of HCQ.

TRIAL REGISTRATION

ChiCTR2300070628.

Smoking is associated with elevated blood level of volatile organic compounds: a population-based analysis of NHANES 2017-2018

BACKGROUND

The study aims to explore the association between cigarette smoking with blood exposure to volatile organic compounds using population data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018.

METHODS

Based on the data of NHANES 2017-2018, we identified 1117 participants aged 18 to 65 years, who had complete VOCs testing data and filled out the Smoking-Cigarette Use and Volatile Toxicant questionnaires. The participants consisted of 214 dual-smoking persons, 41 E-cigarette smokers, 293 combustible-cigarette smokers and 569 non-smokers. We used One-way ANOVA and Welch's ANOVA to compare differences of VOCs concentration among 4 groups and multivariable regression model to confirm the factors associated with VOCs concentration.

RESULTS

In dual-smoking and combustible-cigarette smokers, blood concentration of 2,5-Dimethylfuran, Benzene, Benzonitrile, Furan, Isobutyronitrile were higher than non-smokers. When compared with people who never smoked, E-cigarette smokers had similar blood concentrations of VOCs. Blood concentrations of Benzene, Furan, and Isobutyronitrile were significant higher in combustible-cigarette smokers than in E-cigarette smokers. In the multivariable regression model, dual-smoking and combustible-cigarette smoking were associated with elevated blood concentrations of several VOCs except 1,4-Dichlorobenzene, while E-cigarette smoking was only associated with elevated 2,5-Dimethylfuran concentration.

CONCLUSIONS

Smoking, mainly dual-smoking and combustible-cigarette smoking, is associated with elevated blood concentration of VOCs, while the effect is weak in E-cigarette smoking.

Low estimated glomerular filtration rate is an independent risk factor for higher hydroxychloroquine concentration

BACKGROUND

The aim of this study was to analyze the relationship of the estimated glomerular filtration rate (eGFR) to hydroxychloroquine (HCQ) blood concentrations in systemic lupus erythematosus (SLE) patients.

METHOD

Patients with SLE who had been taking HCQ for more than 12 months were recruited. All subjects gave written informed consent. Various clinical characteristics and laboratory values were examined. The blood concentration of HCQ was measured by high-performance liquid chromatography, and the relationship of eGFR to HCQ blood concentration was mainly investigated.

RESULT

In total, 115 patients with SLE receiving long-term HCQ therapy were included in the study. The median concentration of HCQ was 1096 ng/ml (range 116-8240 ng/ml). The eGFR was strongly associated with blood concentration of HCQ (P = 0.011, P < 0.05), when adjusted for age, sex, body mass index (BMI), weight-adjusted dose, prednisone use and immunosuppressive drug use. No statistically significant association were found between age, duration, BMI, weight-adjusted HCQ dose, corticosteroid use, immunosuppressant use and blood concentrations of HCQ.

CONCLUSION

We provided novel evidence that impaired renal function influenced the blood concentration of HCQ. Patients with low eGFR need to adjust the HCQ dosage according to the monitoring results of HCQ blood concentrations.

Blood Concentration of Cabazitaxel in a Patient Whose General Condition Worsened with Concomitant Use of Clarithromycin

We encountered a case in which the general condition of a patient receiving cabazitaxel worsened with concomitant use of clarithromycin. Cabazitaxel is metabolized mainly by CYP3A4, and the frequency of adverse events is known to increase with increasing exposure. Although these drugs are not often quantified in daily practice, we quantified them because we considered it possible that the blood concentration of cabazitaxel had increased due to CYP3A4 inhibition of clarithromycin and that cabazitaxel-related adverse events had occurred. However, the concentration of cabazitaxel was not increased and we attributed the patient's deterioration to decreased tolerability of cabazitaxel. At least at a trough concentration of 70 ng/mL, which is the trough concentration when a normal dose of clarithromycin is administered, clarithromycin does not appear to have a significant effect on the blood concentration of cabazitaxel. This case suggests that the administration of the normal dose of clarithromycin might be relatively safe in patients receiving cabazitaxel.

Approaches to mixture risk assessment of PFASs in the European population based on human hazard and biomonitoring data

Per- and polyfluoroalkyl substances (PFASs) are a highly persistent, mobile, and bioaccumulative class of chemicals, of which emissions into the environment result in long-lasting contamination with high probability for causing adverse effects to human health and the environment. Within the European Biomonitoring Initiative HBM4EU, samples and data were collected in a harmonized way from human biomonitoring (HBM) studies in Europe to derive current exposure data across a geographic spread. We performed mixture risk assessments based on recent internal exposure data of PFASs in European teenagers generated in the HBM4EU Aligned Studies (dataset with N = 1957, sampling years 2014-2021). Mixture risk assessments were performed based on three hazard-based approaches: the Hazard Index (HI) approach, the sum value approach as used by the European Food Safety Authority (EFSA) and the Relative Potency Factor (RPF) approach. The HI approach resulted in the highest risk estimates, followed by the RPF approach and the sum value approach. The assessments indicate that PFAS exposure may result in a health risk in a considerable fraction of individuals in the HBM4EU teenager study sample, thereby confirming the conclusion drawn in the recent EFSA scientific opinion. This study underlines that HBM data are of added value in assessing the health risks of aggregate and cumulative exposure to PFASs, as such data are able to reflect exposure from different sources and via different routes.

Clinical impact of the dose and blood concentration of lacosamide in Japanese pediatric patients with epilepsy: A cohort study

PURPOSE

The relationship between treatment efficacy/tolerability and the dose/blood concentration of lacosamide (LCM) was investigated in a clinical cohort of Japanese pediatric patients with epilepsy.

METHODS

This retrospective analysis reviewed the medical records of patients treated with LCM for >6 months at the Department of Pediatrics, Hiroshima University Hospital, from September 2017 to January 2021. The collected data included age, sex, epilepsy type, seizure type, seizure frequency before and after treatment initiation, adverse events leading to LCM discontinuation, dose at any evaluation point, serum concentration, and concomitant antiepileptic drugs (AEDs).

RESULTS

The study included 51 patients (31 male patients) between the ages of 2 and 19 years. All patients were Japanese. Epilepsy was classified as focal in 44 patients, generalized in six patients, and combined generalized and focal in one patient. The 50% responder rate for LCM treatment was 56.9%. Seven patients experienced complete seizure control (absence of seizures for 6 months before the follow-up visit). A relationship between dose and blood concentration was identified. Although the blood LCM concentration was higher in the responders than in the nonresponders (7.86 vs. 6.16 μg/mL; p = 0.028), there was no significant difference in dose between the two groups. Lacosamide showed efficacy at a dose >5 mg/kg/day in more than half of the 50% responders. The treatment-emergent adverse events (TEAEs) included seizure aggravation in five patients, irritability in two patients, and somnolence and drug eruption in one patient each. In six patients with TEAEs, the TEAEs developed within 1 month after treatment initiation and led to LCM discontinuation.

CONCLUSION

In Japanese pediatric patients with epilepsy, LCM treatment is effective, particularly at higher doses. The blood concentration may be related more to efficacy than to dose. Lacosamide is generally well-tolerated by pediatric patients, and should be used at the maximum tolerable dose (needed to be gradually increased) in patients with otherwise insufficient seizure control. As TEAEs leading to discontinue treatment likely occur in early phase, it is needed to monitor patients carefully if TEAEs would happen in that phase.

Maternal blood concentration of tadalafil in pregnancy: Comparison of pregnant and non-pregnant women

OBJECTIVE

In this study, the drug kinetics of tadalafil were compared between pregnant and non-pregnant women to determine the ideal dosage to promote uterine blood flow.

MATERIALS AND METHODS

We recruited five pregnant and five non-pregnant women, all of which were administered tadalafil (20 mg/day). The blood concentration of tadalafil was measured 1, 2, 4, 6, 8, and 24 h after administration. We investigated the side effects within 4 days of tadalafil administration and compared the cumulative frequency between the two groups.

RESULTS

The mean area under the concentration-time curve and maximum blood concentration of tadalafil were not different between the pregnant and non-pregnant groups. Time to maximum blood concentration was delayed by 1 min on average in the pregnant group compared with the non-pregnant group. The cumulative frequency of side effects was significantly lower in the pregnant group than in the non-pregnant group (P = 0.026). No side effects were observed in either group after the fifth day of the tadalafil administration.

CONCLUSION

Although there was no difference in maximum blood concentration between non-pregnant and pregnant women, the rate of side effects was lower in pregnant women than in non-pregnant women. Therefore, pregnant women may tolerate tadalafil better.

Relationship of cytochrome P450 gene polymorphisms with blood concentrations of hydroxychloroquine and its metabolites and adverse drug reactions

Background

Hydroxychloroquine (HCQ) is a cornerstone therapy for systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). This study aimed to investigate the relationship of cytochrome P450 (CYP450) gene polymorphisms with blood concentrations of HCQ and its metabolites and adverse drug reactions (ADRs) in patients with SLE and RA.

Methods

A cohort of 146 patients with SLE and RA treated with HCQ was reviewed. The ADRs of the patients were recorded. The blood concentrations of HCQ and its metabolites were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Genotyping of single nucleotide polymorphisms (SNPs) in CYP450, a metabolic enzyme involved in the HCQ metabolic pathway, was performed using a MassARRAY system. The chi-square test, T-test, and one-way analysis of variance were used to analyse data.

Results

Among 29 candidate SNPs, we found that CYP3A4 (rs3735451) was significantly associated with blood levels of HCQ and its metabolites in both the unadjusted model and adjusted model (patients taking HCQ for > 10 years) (P < 0.05). For CYP3A5 (rs776746), a greater risk of skin and mucous membrane ADRs was associated with the TT genotype than with the CT + CC genotypes (P = 0.033). For CYP2C8 (rs1058932), the AG genotype carried a greater risk of abnormal renal function than the AA + GG genotype (P = 0.017); for rs10882526, the GG genotype carried a greater risk of ophthalmic ADRs than the AA + AG genotypes (P = 0.026).

Conclusions

The CYP2C8 (rs1058932 and rs10882526) and CYP3A5 (rs776746) polymorphisms are likely involved in the ADRs of HCQ. Gene polymorphism analysis of CYP450 and therapeutic drug monitoring of HCQ and its metabolites might be useful to optimise HCQ administration and predict ADRs.

Relationship between tracheal intubation and the drugs used by patients with drug overdose due to self-harm

Background

Tracheal intubation may be performed in patients with drug overdose due to self-harm; however, the details of the causative drug are unknown. The purpose of this study was to clarify the relationship between drugs or its blood levels of patients with drug overdose and the need for tracheal intubation based on the actual measurement results.

Methods

From October 2018 to March 2020, 132 patients with drug overdose due to self-harm who were transported to the emergency department (ED) were studied. Patient drugs were measured using gas chromatography–mass spectrometry (GC-MS) and were analyzed on the basis of the GC/MS Forensic Toxicological Database. Logistic analysis was performed by combining patient information and GC-MS information.

Results

The Glasgow Coma Scale (GCS) and Japan Coma Scale (JCS) efficiently predicted tracheal intubation in patients with drug overdose during transport triage; GCS (cut-off value: 12, area under the curve (AUC): 0.81, 95% confidence interval (CI): 0.71–0.88, sensitivity: 0.85, specificity: 0.71, P < 0.05) and JCS (cut-off value: 3, AUC: 0.74, 95% CI: 0.60–0.84, sensitivity: 0.60, specificity: 0.84, P < 0.05). The drugs detected in all patients with drug overdose in order were benzodiazepine receptor agonists (BZs; 43.9%), anticonvulsants (38.6%), antipsychotics (25.0%), and antidepressants (9.8%). In univariate logistic analysis, antipsychotics (odds ratio (OR) 2.46, 95% CI 1.19–5.20, P < 0.05), anticonvulsants (OR 2.71, 95% CI 1.26–5.98, P < 0.05), and anticonvulsants above alert blood levels (OR 27.8, 95% CI 2.92–264.1, P < 0.05) were significantly associated with tracheal intubation in patients with drug overdose, but not BZs and antidepressants. Also, in multivariate logistic analysis, antipsychotics (OR 2.27, 95% CI 1.07–4.83, P < 0.05), anticonvulsants (OR 2.50, 95% CI 1.14–5.64, P < 0.05) and in multivariate logistic analysis of blood levels, anticonvulsants above the alert blood levels (OR 24.9, 95% CI 2.56–241.6, P < 0.05) were significantly associated with tracheal intubation in patients with drug overdose respectively.

Conclusions

Logistic analysis revealed that the use of anticonvulsants and antipsychotics were significantly associated with an increased OR in the tracheal intubation of patients with drug overdose due to self-harm.

Higher teicoplanin blood level needed in elderly critically ill patients

BACKGROUND

Significant changes in the pathophysiology of older critically ill patients may affect the pharmacokinetics and pharmacodynamics of teicoplanin. This study aimed to determine the optimal teicoplanin blood level in this patient population.

MATERIALS & METHODS

128 older critically ill and 86 older non-critically ill patients were involved and analyzed.

RESULTS

The target thresholds of teicoplanin blood concentrations in older critically ill patients and non-critically ill patients should be 31.4mg/L and 15.3mg/L, respectively. The dose of teicoplanin in older critically ill patients should be greater than 800 mg to achieve the target blood level.

CONCLUSION

An individualized dosing approach of teicoplanin based on therapeutic drug monitoring is necessary for older critically ill patients.

Relationship between cocaine and cocaethylene blood concentration with the severity of clinical manifestations

BACKGROUND

Poisonings resulting from the abuse of drugs currently represent a serious problem for public health. Among the main agents involved, cocaine stands out. It became one of the most abused drugs around the world, and one of the main reasons for visits to the emergency department due to the use of illicit substances. The use of cocaine is primarily in combination with alcoholic beverages. There are few studies that correlate cocaine blood concentration and the severity of clinical manifestations in patients evaluated at Emergency Department. The aim of the present study was to verify the possible relationship between the blood concentration of cocaine and cocaethylene (product of the interaction of cocaine with ethanol) with the severity of the clinical manifestations presented by patients with cocaine intoxication.

METHODS

Blood levels were measured by high-performance liquid chromatography (HPLC) and the severity of clinical manifestations was assessed using the Stimulant Intoxication Score (SIS). To establish this relationship, Pearson's chi-square statistical test (x²) was used for categorical variables and Student's t for continuous variables, with statistical significance of 5% (p < 0.05).

RESULTS

Of the 81 patients included in the study, 77.8% were men with a mean age of 32.5 years ± 8.5 and mean of SIS 3.4 ± 2.5. Considering the toxicological analysis results, 24.7% of the blood samples were positive. The mean of cocaine and cocaethylene concentrations were 0.34 μg/mL ± 0.45 and 0.38 μg/mL ± 0.34, respectively. The blood concentration of cocaine and cocaethylene has not been shown to be useful information for the treatment and prognosis of patients, but blood levels of these substances at the time of treatment, regardless of their concentration, may be an indicator of severity, showing that any concentrations of these substances should be considered as potentially toxic.

CONCLUSION

The application of the SIS score proved to be an important alternative capable of predicting the severity of the patients due to cocaine intoxication in a fast and simplified way.

Severe acute intoxication with yohimbine: Four simultaneous poisoning cases

Yohimbine is an indole alkaloid from the leaves and bark of the Pausinystalia johimbe tree that has acquired an enviable reputation in treating erectile dysfunction. This report presents four simultaneous severe poisoning/death cases caused by yohimbine. The test samples comprised the venous blood of four middle-aged men (aged 47-65) who were suspected of poisoning; one of the men died due to ineffective rescue. Ethanol concentration determination and toxicological routine screening were performed using gas chromatography with flame ionization detection (GC-FID) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). A specific LC-MS/MS method was developed to quantify yohimbine, which showed concentrations of 459, 249, and 301ng/mL in three poisoned blood samples and concentrations as high as 5631ng/mL in the deceased. Moreover, the deceased's autopsy ruled out death from trauma and previous illness, and no other common toxic components were detected in his blood. Therefore, yohimbine poisoning appears to be the most likely cause of death. As a type of alkaloid that can be employed in the treatment of clinical diseases and additives for supplements, the danger of yohimbine should be of widespread concern in society.

Evaluating consumer exposure to disinfecting chemicals against coronavirus disease 2019 (COVID-19) and associated health risks

Disinfection of surfaces has been recommended as one of the most effective ways to combat the spread of novel coronavirus (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19). However, overexposure to disinfecting chemicals may lead to unintended human health risks. Here, using an indoor fate and chemical exposure model, we estimate human exposure to 22 disinfecting chemicals on the lists recommended by various governmental agencies against COVID-19, resulting from contact with disinfected surfaces and handwashing. Three near-field exposure routes, i.e., mouthing-mediated oral ingestion, inhalation, and dermal absorption, are considered to calculate the whole-body uptake doses and blood concentrations caused by single use per day for three age groups (3, 14, and 24-year-old). We also assess the health risks by comparing the predicted whole-body uptake doses with in vivo toxicological data and the predicted blood concentrations with in vitro bioactivity data. Our results indicate that both the total exposure and relative contribution of each exposure route vary considerably among the disinfecting chemicals due to their diverse physicochemical properties. 3-year-old children have consistent higher exposure than other age groups, especially in the scenario of contact with disinfected surfaces, due to their more frequent hand contact and mouthing activities. Due to the short duration of handwashing, we do not expect any health risk from the use of disinfecting chemicals in handwashing. In contrast, exposure from contact with disinfected surfaces may result in health risks for certain age groups especially children, even the surfaces are disinfected once a day. Interestingly, risk assessments based on whole-body uptake doses and in vivo toxicological data tend to give higher risk estimates than do those based on blood concentrations and in vitro bioactivity data. Our results reveal the most important exposure routes for disinfecting chemicals used in the indoor environment; they also highlight the need for more accurate data for both chemical properties and toxicity to better understand the risks associated with the increased use of disinfecting chemicals in the pandemic.

Chorea-like symptoms and high blood concentration of ceftriaxone in a patient undergoing hemodialysis: A case report

Ceftriaxone (CTRX) is a third-generation cephalosporin commonly used to treat infections such as community-acquired pneumonia and urinary tract infections caused by mainly Gram-negative bacteria and some Gram-positive bacteria. Here, we report a case of a patient on hemodialysis who had chorea-like symptoms with high blood concentration of CTRX. A 74-year-old Japanese woman receiving hemodialysis was admitted with obstructive cholangitis and was started on CTRX therapy at a dose of 2 g every 24 hours. On the 6th day after starting administration of CTRX, chorea-like symptoms appeared. We suspected that her symptoms were caused by a high blood concentration of CTRX. We performed a series of blood sampling to determine the concentration of CTRX at different time points before and after discontinuing CTRX administration. CTRX concentrations were higher than those expected in healthy adults, and her chorea-like symptoms had disappeared from the second day of discontinuation of CTRX. The association between CTRX blood concentration and chorea-like symptoms is unclear. However, measuring a series of plasma or serum concentrations from symptom onset to disappearance suggested that chorea-like symptoms appeared when the concentration exceeded approximately 450 μg/mL. Care should be taken when administering CTRX to patients with cholestasis undergoing hemodialysis, as blood CTRX levels may rise unexpectedly and result in complications.

Sustainable Effects of Distigmine Bromide on Urinary Bladder Contractile Function

Distigmine bromide (distigmine) is a reversible carbamate cholinesterase (ChE) inhibitor that is used to treat myasthenia gravis. In Japan, it is also used as a remedy for urination disorder (underactive bladder). The most distinctive pharmacological feature of distigmine is its long-lasting action compared to that of other ChE inhibitors. In animals and humans, distigmine was reported to inhibit acetylcholinesterase (AChE) and improve myasthenia gravis for an extended period. Few studies have examined the sustainability of this enhancing effect on the contractile function of urinary bladder smooth muscle. In addition, the cause of this long-lasting feature remains unclear. In this review, we present our findings for the long-lasting feature of distigmine on isolated urinary bladder contraction and in vivo urinary function of guinea pig. We also present our results on the mechanism of its long-lasting sustainability using recombinant human AChE.

Blood concentration, efficacy, and adverse events of phenobarbital: A prospective study in rural China

OBJECTIVE

This study evaluated the relationship between blood concentration of phenobarbital (PB) and its efficacy as well as adverse events in people with epilepsy in rural China.

METHODS

People with epilepsy being treated with PB monotherapy were recruited and followed up for averagely 2.5 years. Data of clinical characteristics were collected using a standardized questionnaire by face-to-face interviews both at baseline and follow-up. Plasma concentration of PB was detected by the high-performance liquid chromatography.

RESULTS

Data on treatment response and PB blood concentration was obtained from 225 subjects. Among them, 119 (52.9%) were recognized as effective cases and 106 (47.1%) as ineffective cases. In the effective group, the blood concentration of 95% subjects ranged from 1.22 μg/ml to 41.36 μg/ml with a median at 13.18 μg/ml (IQR = 8.32-20.19 μg/ml). The PB concentration of 95% of the subjects in the ineffective group ranged from 2.73 μg/ml to 70.16 μg/ml with a median at 19.80 μg/ml (IQR = 11.30-30.40 μg/ml), which was significantly higher than that of the effective group (p < 0.001). Multivariate logistic regression analysis showed that PB concentration ≥26.38 μg/ml was related to a 4.5-fold (95% confidence interval [CI], 1.85-11.08) higher risk of inefficacy. A receiver operation characteristic curve was performed to determine the cutoff value of concentration for PB efficacy at 19.02 μg/ml.

SIGNIFICANCE

Blood concentration may be an important indicator for clinical decision making when PB monotherapy cannot achieve a good efficacy and more attention should be paid on it in clinical practice especially in resource-poor settings.

Criminal mercury vapor poisoning using heated tobacco product

We report an unusual case of mercury vapor poisoning from using a heated tobacco product. The suspect had added grains of mercury into 20 cigarettes in a pack. When a 36-year-old Japanese man inserted one of these cigarettes into the battery powered holder, it was heated to a temperature of 350 °C, and he inhaled vaporized mercury. After using 14 of the cigarettes over 16 h, he noticed he had flu-like symptoms so he visited the hospital. Although no physical abnormalities were revealed, 99 μg/L of mercury was detected in his serum sample. His general condition improved gradually and his whole blood mercury level had decreased to 38 μg/L 5 days later. When the remaining six cigarettes in the pack were examined, many metallic grains weighing a total of 1.57 g were observed. Energy dispersive X-ray fluorescence spectrometry confirmed the grains as elemental mercury. Accordingly, the victim was diagnosed with mercury poisoning. Because the mercury was incorporated into cigarettes, an unusual and novel intoxication occurred through the heating of the tobacco product. Both medical and forensic scientific examination confirmed this event as attempted murder.

Blood concentrations of a new psychoactive substance 4-chloromethcathinone (4-CMC) determined in 15 forensic cases

Purpose

The 4-chloromethcathinone (4-CMC) is a synthetic derivative of cathinone and belongs to new psychoactive substances. Neither data on the effects of 4-CMC on the human body, nor on nontoxic, toxic and lethal concentrations in biological materials have been published in the literature. This paper describes the results of an analysis of the blood concentrations of 4-CMC determined in 15 forensic cases related to nonfatal intoxication including driving under the influence, and fatalities including overdoses, suicide and traffic accidents.

Methods

A new method for the quantification of 4-CMC using gas chromatography-mass spectrometry (GC-MS) was developed. The symptoms of 4-CMC use were also studied based on an analysis of the documents prepared during the collection of samples or at autopsies.

Results

The limits of detection and quantification of the method for blood samples were 0.3 and 1 ng/mL, respectively. The calibration curve was linear in the studied concentration range (1-500 ng/mL) with the correlation coefficient at 0.9979. The extraction recoveries varied in the range of 94.3-98.8%. The accuracy and precision were acceptable. The determined concentrations in nonfatal cases ranged from 1.3 to 75.3 ng/mL, and in fatalities from 56.2 to 1870 ng/mL.

Conclusions

Our study can assist in the recognition of the possible effects caused by 4-CMC and can be helpful during the preparation of forensic toxicological opinions for courts of law. The validation parameters indicate the sensitivity and accuracy of the method. This is the first work presenting a validated method for the determination of 4-CMC in blood samples by GC-MS.

Changes in coumarin kinetics and subcellular localization of CYP2E1 contribute to bile duct damage and reduce hepatocellular damage after repeated administration of coumarin in rats

Coumarin exhibits different hepatotoxicity in rats depending on the administration frequency. To investigate the underlying mechanisms for the differences, we administered coumarin to rats as a single dose or repeatedly for 4 weeks. We found large increases in blood levels of liver enzymes and noticeable centrilobular hepatic necrosis after a single dose of coumarin. After repeated administration, enzyme levels mildly increased, while those of γ-GTP and total bilirubin significantly increased, suggesting bile duct damage. In the control group, cytochrome P450 2E1 (CYP2E1) showed a diffuse subcellular distribution but accumulated within the hepatocyte endoplasmic reticulum after repeated coumarin administration. The maximum blood concentrations of coumarin and its metabolites were significantly lower upon repeated administration. The results suggest that changes in coumarin pharmacokinetics and CYP2E1 subcellular distribution contribute to resistance to coumarin-induced hepatic necrosis, while cytotoxicity of metabolic conjugates shown in vitro may contribute to bile duct damage upon repeated coumarin administration.

Determination of glyphosate and its metabolite in emergency room in Korea

The number of glyphosate intoxication cases has been increased after the regulation of paraquat. Unfortunately, there are no reports on the potential concentration of glyphosate for those acute intoxicated patients admitted to emergency rooms and the correlation between the concentration of glyphosate and clinical symptoms in Korea up to our knowledge. As a nonselective herbicide, analysis of glyphosate requires derivatization because of its amphoteric and strongly polar nature. In order to develop a method to determine the concentration of glyphosate and its metabolite, aminomethylphosphonic acid (AMPA) in blood samples without derivatization, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was utilized with a hydrophilic interaction chromatography (HILIC) column. The validation of this method showed that the limits of detection (LODs) and limits of quantitation (LOQs) for glyphosate and AMPA were 50 and 100ng/mL, respectively. In addition, matrix effect, recovery rate, and accuracy and precision in intra and inter-day were evaluated during the validation study of this method. Blood samples acquired from five glyphosate intoxicated patients were analyzed to investigate the correlation between the concentration of glyphosate and clinical symptoms. These patients were previously admitted to the emergency room at a University Hospital in Korea after glyphosate was self-administered in suicide attempts or by accident. As results of blood sample study, the concentration of glyphosate and AMPA were found in the range of 1.0-171.1 and 0.2-2.6μg/mL, respectively. The concentration ratio of glyphosate to AMPA was 55-71. According to the clinical reports for those patients, they were in the age between 47 and 82 years old and administered about 50-400mL. The blood samples were collected within 2-5h after administration of glyphosate. Among the intoxicated patients, the most common clinical symptom was metabolic acidosis, identified in four patients. The comparison between the concentration of glyphosate and administered dosage did not show the correlation, which suggests further investigation on the effects of surfactants in glyphosate from different vendors.

Effect of colestimide on the concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dizenzofurans, and polychlorinated biphenyls in blood of Yusho patients

BACKGROUND

Oral colestimide was reported to lower the concentration of PCDDs, PCDFs, and PCB in the blood of humans. A pilot study showed that the arithmetic mean total TEQ concentrations of PCDDs, PCDFs, and PCBs in the blood of subjects after the trial decreased approximately 20 % compared to pre-trial levels, suggesting that colestimide could decrease human dioxin levels. We designed the current clinical trial study based on this information. In this study, we examined whether colestimide could reduce the individual congener concentrations of PCDDs, PCDFs, and PCBs in the blood of Yusho patients.

METHODS

Out of the 36 Yusho patients who participated in the clinical trial, 26 patients self-administered colestimide 3 g/day orally for 6 months. The concentrations of PCDDs, PCDFs and PCBs in the blood of 26 Yusho patients before the trial were compared with those after the trial.

RESULTS

The arithmetic mean total TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in the blood of the 26 Yusho patients before and after the clinical trial were 42-303 (mean: 130, median: 120) and 43-283 (mean: 132, median: 118) pg TEQ/g lipid, respectively. The sums of the concentrations of 58 PCB congeners measured in the blood of Yusho patients before and after the trial were 321-2643 (mean: 957, median: 872) and 286-2007 (mean: 975, median: 806) ng/g lipid, respectively, indicating that the concentrations of PCDDs, PCDFs, and PCBs after the trial were almost the same as those before the trial. Among congeners of PCDDs, PCDFs, dioxin-like PCBs, and non-dioxin-like PCBs, most congeners of these compounds did not show a statistically significant decrease after the trial.

CONCLUSION

Colestimide may not be beneficial in reducing the high blood levels of dioxin-like compounds in Yusho patients.

The therapeutic use of cannabinoids: Forensic aspects

Since 2013 in the Italian market has been introduced the Nabiximols, a drug containing two of the main active cannabinoids: Δ(9)-tetrahydrocannabinol (Δ(9)-THC) and cannabidiol (CBD). This drug has been approved in Italy in the treatment of Multiple Sclerosis (MS). It is an oral spray formulation and each puff of 100μl contains 2.7mg of Δ(9)-THC and 2.5mg of CBD. In the present study we analyzed urine and blood samples collected from a group of 20 patients treated with Nabiximols in order to evaluate: blood Δ(9)-THC concentrations in relation to the dose administered and the duration of treatment and the potentiality of this medication to be used for drug habit.

METHODS

The study was conducted on a sample group of patients affected by MS, of both sexes, age: 49-61 years, treated with Nabiximols for short (28 days) or long-term. The results of our study allow affirming that it is unlikely to use this medication for drug habit or to sale it in the black market because of the low blood concentrations available and of its high costs. These statements were confirmed by: (a) the low Δ(9)-THC concentrations in the pharmaceutical formulation; (b) the low blood concentrations produced by Nabiximols administration, more than 10 times smaller than the blood concentrations known to produce psychotropic effects; (c) the presence of CBD (Δ(9)-THC natural antagonist); (d) the route of administration (inhaled, not smoked).

Therapeutic Dose Monitoring for Linezolid in a Patient with MRSA Pneumonia with Bacteremia in Diabetes Insipidus

INTRODUCTION

Few studies have investigated the effect of increased creatinine clearance (CrCl) on linezolid (LZD) concentration. Herein, we report the pharmacokinetic/pharmacodynamic (PK/PD) profile of LZD used in the management of methicillin-resistant Staphylococcus aureus (MRSA) pneumonia with concomitant bacteremia in a patient with high CrCl caused by diabetes insipidus (DI).

CASE REPORT

A 19-year-old man was admitted to the intensive care unit following a traumatic brain injury. After admission, he underwent a craniotomy for the severe brain injury. However, he developed DI after the operation. Despite treatment with vasopressin, his urine output reached 5-6 L/day as a result of the DI, and his CrCl increased to 180-278 mL/min. We were required to administer 6-7 L of fluid a day to compensate for the high urinary fluid output. On day 55, MRSA pneumonia with sepsis was suspected and, consequently, LZD was administrated intravenously (600 mg every 12 h). He was treated with LZD for 14 days. The patient has since successfully recovered from MRSA pneumonia with concomitant bacteremia, and was transferred to the general ward on day 82. Blood LZD levels from days 60-68, which were measured after the patient's transfer to the general ward, showed that the trough levels were lower than the threshold level of detection. The blood 24-h area under the plasma LZD concentration-time curve (AUC)24/minimum inhibitory concentration (MIC) was 69.3.

CONCLUSION

In spite of the low level of LZD AUC24/MIC caused by the high CrCl with DI, MRSA pneumonia with concomitant bacteremia was successfully treated with LZD.

Successful treatment of a case with concurrent ingestion of carbamazepine overdose and grapefruit juice

Case

We report a case with concurrent ingestion of carbamazepine (CBZ) overdose and grapefruit juice. A 23-year-old man, with a history of epilepsy, was admitted to our emergency department 2 h after ingesting 10 g CBZ with 1 L grapefruit juice. On arrival, the patient's Glasgow Coma Scale score was 9 and he showed signs of restlessness. Grapefruit juice-like gastric fluid, with tablet residue, was observed in his stomach after we inserted a gastric tube. Our initial test detected a blood CBZ level of 41.5 mg/L.

Outcome

We treated the patient with gastric lavage, activated charcoal, and charcoal hemoperfusion. His blood CBZ level began to decrease after gastrointestinal decontamination, and he was discharged without any sequelae on day 9.

Conclusion

Gastric lavage or aspiration may be considered in cases where drug residue is found in the stomach, especially if materials are involved that might exacerbate the drug's toxicity.

Withdrawal reaction of carbamazepine after neurovascular decompression for trigeminal neuralgia: a preliminary study

OBJECTIVE

To evaluate the representations and the relevant factors of carbamazepine-associated withdrawal reaction (CAWR) after microvascular decompression (MVD) to treat trigeminal neuralgia (TN).

METHODS

The present series included 90 patients who were referred from September 2010 to January 2013 and diagnosed with classical TN. The carbamazepine (CBZ) serum level was tested twice at 24h pre- and 24h post-operation by using HPLC analysis. The analysis of correlating selected factors and CAWR was performed.

RESULTS

Among 90 patients, 26 (28.9%) suffered from post-operative CAWR for 3 days after MVD. The symptoms of CAWR include overexcitement, e.g. insomnia, dysphoria, hand fremitus, hallucination and severe headache. The history of CBZ therapy before MVD, pre-operative dosage of CBZ, and the D-value of CBZ blood concentrations demonstrated statistic differences between the patients with CAWR and those without CAWR. Patient characteristics such as gender, age, and duration of neuralgia, neuralgia-related factors including neuralgia extent and neurovascular compression severity, and operation conditions including duration of MVD procedure, effect of MVD and complication of MVD had no influence on the occurrence of CAWR.

CONCLUSION

It is strongly suggested that CAWR is dependent on the pre-operative dosage and the changing rate of pre- and post-operative CBZ blood concentrations.

Tacrolimus dosage requirements in living donor liver transplant recipients with small-for-size grafts

AIM: To investigate the tacrolimus dosage requirements and blood concentrations in adult-to-adult right lobe living donor liver transplantation (AALDLT) recipients with small-for-size (SFS) grafts.

METHODS: During January 2007 and October 2008, a total of 54 cases of AALDLT with an observation period of 6 mo were enrolled in this study. The 54 patients were divided into two groups according to graft-recipient body weight ratio (GRBW): SFS grafts group (Group S, GRBW < 0.8%, n = 8) and non-SFS grafts group (Group N, GRBW ≥ 0.8%, n = 46). Tacrolimus 12-hour blood levels and doses were recorded during weeks 1, 2, 3 and 4 and months 2, 3, 4, 5 and 6 in group S and group N. Meanwhile, acute rejection rates, liver and renal function test results, and the number of potentially interacting medications were determined at each interval in the two groups. A comparison of tacrolimus dosage requirements and blood levels were made weekly in the first month post-surgery, and monthly from months 2 to 6.

RESULTS: There were no differences in the demographic characteristics, acute rejection rates, liver and renal function test results, or the number of potentially interacting medications administered between the two groups. The tacrolimus dosage requirements in group S were significantly lower than group N at 2 wk (2.8 ± 0.4 mg/d vs 3.6 ± 0.7 mg/d, P = 0.006), 3 wk (2.9 ± 0.7 mg/d vs 3.9 ± 0.8 mg/d, P = 0.008), 4 wk (2.9 ± 0.8 mg/d vs 3.9 ± 1.0 mg/d, P = 0.023) and 2 mo (2.8 ± 0.7 mg/d vs 3.8 ± 1.1 mg/d, P = 0.033). Tacrolimus 12-h trough concentrations were similar between the two groups at all times except for 2 wk post-transplantation, when the concentrations were significantly greater in group S recipients than in group N recipients (11.3 ± 4.8 ng/mL vs 7.0 ± 3.8 ng/mL, P = 0.026).

CONCLUSION: SFS grafts recipients have significantly decreased tacrolimus dosage requirements compared with non-SFS grafts recipients in AALDLT during the first 2 mo post-surgery.