Semi-physiological Pharmacokinetic Model of Clozapine and Norclozapine in Healthy, Non-smoking Volunteers: The Impact of Race and Genetics.

BACKGROUND AND OBJECTIVES: Clozapine is the medication of choice for treatment-resistant schizophrenia. However, it has a complex metabolism and unexplained interindividual variability. The current work aims to develop a pharmacokinetic model of clozapine and norclozapine in non-smokers and assess the impact of demographic and genetic predictors. METHODS: Healthy volunteers were recruited in a population pharmacokinetic study. Blood samples were collected at 30 min and 1, 2, 3, 5 and 8 h following a single flat dose of clozapine (12.5 mg). The clozapine and norclozapine concentrations were measured via high-performance liquid chromatography-ultraviolet method. A semi-physiological pharmacokinetic model of clozapine and norclozapine was developed using nonlinear mixed-effects modeling. Clinical and genetic predictors were evaluated, including CYP1A2 (rs762551) and ABCB1 (rs2032582), using restriction fragment length polymorphism. RESULTS: A total of 270 samples were collected from 33 participants. The data were best described using a two-compartment model for clozapine and a two-compartment model for norclozapine with first-order absorption and elimination and pre-systemic metabolism. The estimated (relative standard error) clearance of clozapine and norclozapine were 27 L h-1 (31.5 %) and 19.6 L h-1 (30%), respectively. Clozapine clearance was lower in sub-Saharan Africans (n = 4) and higher in Caucasians (n = 9) than Asians (n = 20). Participants with CYP1A2 (rs762551) (n = 18) and ABCB1 (rs2032582) (n = 12) mutant alleles had lower clozapine clearance in the univariate analysis. CONCLUSIONS: This is the first study to develop a semi-physiological pharmacokinetic model of clozapine and norclozapine accounting for the pre-systemic metabolism. Asians required lower doses of clozapine as compared with Caucasians, while clozapine pharmacokinetics in sub-Saharan Africans should be further investigated in larger trials.

Investigating the Association Between Type 2 Diabetes Mellitus and Pathological Responses Among Breast Cancer Patients Receiving Neoadjuvant Chemotherapy.

INTRODUCTION: The relationship between type 2 diabetes mellitus (T2DM) and pathological responses after neoadjuvant chemotherapy (NACT) is controversial. In this study, we aim to determine the association of pathological responses in breast cancer women with T2DM after receiving NACT. METHODS: Medical records of breast cancer women with T2DM who received NACT from January 2016 to January 2021 at the medical center in the Gujranwala Institute of Nuclear Medicine and Radiotherapy, Pakistan, were identified and retrieved retrospectively. Variables, including pathological responses, diabetes status, and other clinical data, were collected. Patients were grouped as diabetic and nondiabetic based on the doctor's diagnosis or the diabetic's medication history recorded upon the breast cancer diagnosis. Factors influencing the pathological complete response (pCR) were determined using multivariate logistic regression utilizing IBM SPSS Statistics (version 20). RESULTS: A total of 1372 patient files who received NACT and breast cancer surgery from January 2016 to January 2021 were selected. Out of 1372 breast cancer women receiving NACT, 345 (25.1%) had pre-existing diabetes, while 1027 (74.85%) were without pre-existing diabetes. The most common molecular subtypes of breast cancer were luminal A and B. Two hundred fifty-eight patients (18.8%) had a pCR after receiving NACT. The pCR in diabetic patients was 3.9%, and in nondiabetes, 14.9%. Most women had a pathological partial response (pPR) after the NACT 672 (48.9%). The pPR in diabetic patients was 11.0%, and in nondiabetic patients, it was 38.0%. In nondiabetics, the odds of achieving pPR increase more than pathological no response after the NACT with odd ratio: 1.71 (95% confidence interval: 1.24-2.37). The probability of pCR in patients with luminal B was 1.67 times higher than that in patients with triple-negative breast cancer with odd ratio: 1.67, 95% confidence interval (1.00-2.79), P = 0.05. CONCLUSIONS: The results of the study show that T2DM may have an adverse impact on pCR and pPR following NACT and surgery. Further investigation is needed to explore how changes in blood glucose levels over time impact pathological responses.

The Impact of an Educational Intervention on Enhancing Clinical Knowledge of Physicians and Pharmacists Regarding Statins and Monitoring Parameters: The Experience of a Tertiary Teaching Hospital.

Introduction: Understanding the latest guideline recommendations is crucial for healthcare professionals to apply statin therapy effectively. Thus, the purpose of this study was to evaluate the efficacy of an educational intervention in enhancing the awareness and understanding of physicians and pharmacists concerning risk assessment of Atherosclerotic cardiovascular disease (ASCVD) and the role of statin therapy. Methods: This pre- and post-intervention study was conducted in Sana'a, Yemen's capital city, at the University of Science and Technology Hospital. The study was done between 11/2021-12/2021, and two separate educational sessions were held. The McNemar's test and Wilcoxon signed-rank test were employed as necessary. Results: Participants' awareness of the Framingham CVD risk calculator improved significantly from 40.4% pre-intervention to 78.7% post-intervention. Similarly, understanding of the parameters used in the 10-year ASCVD Risk calculator rose from 46.8% pre-intervention to 76.6% post-intervention. The ability to identify high, moderate, and low-intensity statin therapy, for instance, increased from 34% to 63.8% post-intervention. Regarding statins' contraindications, safety, and efficacy monitoring parameters, pre-intervention knowledge was unsatisfactory, and the educational intervention improved it significantly (p <0.05). For physicians, the median ASCVD risk assessment knowledge score was significantly improved from 4 (IQR = 3-5) pre-intervention to 7 (6.25-8) immediately post-intervention, while the statin therapy clinical knowledge median score significantly improved from 3 (1.25-6.5) to 9 (7.25-14.75) post-education intervention, p-values were 0.002 and 0.003; respectively. For pharmacists, a similar significant improvement (p <0.05) in the overall knowledge scores for both ASCVD risk assessment and statin therapy was noted. Conclusion: The educational intervention improved participants' knowledge of statin therapy and ASCVD risk assessment. Therefore, further education lectures and training programs through continuing medical education on the up-to-date guidelines' recommendations should be regularly implemented to raise awareness and improve the clinical knowledge and appropriateness of statins use in clinical settings. .

Genetic and clinical predictors of rifapentine and isoniazid pharmacokinetics in paediatrics with tuberculosis infection.

OBJECTIVES: Twelve weekly doses of rifapentine and isoniazid (3HP regimen) are recommended for TB preventive therapy in children with TB infection. However, they present with variability in the pharmacokinetic profiles. The current study aimed to develop a pharmacokinetic model of rifapentine and isoniazid in 12 children with TB infection using NONMEM. METHODS: Ninety plasma and 41 urine samples were collected at Week 4 of treatment. Drug concentrations were measured using a validated HPLC-UV method. MassARRAY® SNP genotyping was used to investigate genetic factors, including P-glycoprotein (ABCB1), solute carrier organic anion transporter B1 (SLCO1B1), arylacetamide deacetylase (AADAC) and N-acetyl transferase (NAT2). Clinically relevant covariates were also analysed. RESULTS: A two-compartment model for isoniazid and a one-compartment model for rifapentine with transit compartment absorption and first-order elimination were the best models for describing plasma and urine data. The estimated (relative standard error, RSE) of isoniazid non-renal clearance was 3.52 L·h-1 (23.1%), 2.91 L·h-1 (19.6%), and 2.58 L·h-1 (20.0%) in NAT2 rapid, intermediate and slow acetylators. A significant proportion of the unchanged isoniazid was cleared renally (2.7 L·h-1; 8.0%), while the unchanged rifapentine was cleared primarily through non-renal routes (0.681 L·h-1; 3.6%). Participants with the ABCB1 mutant allele had lower bioavailability of rifapentine, while food prolonged the mean transit time of isoniazid. CONCLUSIONS: ABCB1 mutant allele carriers may require higher rifapentine doses; however, this must be confirmed in larger trials. Food did not affect overall exposure to isoniazid and only delayed absorption time.

Perceptions and Knowledge of Public Towards Emerging Human Monkeypox in Yemen: A Cross-Sectional Study.

Background: The spread of monkeypox (mpox) worldwide poses a severe threat to human life. This virus leads to a disease with symptoms similar to smallpox in humans. To combat this threat, improving public knowledge and perception toward mpox is vital for public health preventive measures. Methods: A cross-sectional survey was carried out in Yemen from December 2022 to March 2023 to investigate public perception and knowledge of mpox. Individuals were approached through social media platforms using a convenient sampling approach. Linear regression was used to determine the association between participants' knowledge (dependent variable) and explanatory variables. Results: A total of 853 individuals consented to take part in the study. A significant proportion of respondents had a low knowledge level (N=572, 67.06%). Most participants knew about the nature of the diseases (75%, n=641), transmission mode (78.1%, n=668), hand sanitizer preventive measures, and skin- related symptoms. However, only 20.8% (n= 178) knew that diarrhea is not a symptom, and 25.4% (n= 217) knew antibiotics are unnecessary for mpox management. A proportion of 57.7% (n=492) of the participants feared human mpox, and 47.7% (n= 407) thought it was a conspiracy. Most participants had a good perception of local and international health authorities controlling the disease. Age, education level, having a health-related certificate, and receiving a 2-dose vaccination for COVID-19 had statistically significant associations with mpox knowledge level (P < 0.05). Social media platforms were the most often used information source about mpox (78.3%, n= 668), followed by articles (41.1%, n=351). Conclusion: The study reveals a low public knowledge about mpox in Yemen, emphasizing the need for targeted educational campaigns, especially via social media, to strengthen public health measures and disease control. Addressing Knowledge gaps and correcting misconceptions is crucial for improving preparedness and response to the disease.

Determinants of Inadequate Empiric Antimicrobial Therapy in ICU Sepsis Patients in Al-Madinah Al-Munawwarah, Saudi Arabia: A Comparison of Artificial Neural Network and Regression Analysis.

In the management of sepsis, providing adequate empiric antimicrobial therapy is one of the most important pillars of sepsis management. Therefore, it is important to evaluate the adequacy of empiric antimicrobial therapy (EAMT) in sepsis patients admitted to intensive care units (ICU) and to identify the determinants of inadequate EAMT. The aim of this study was to evaluate the adequacy of empiric antimicrobial therapy in patients admitted to the ICU with sepsis or septic shock, and the determinants of inadequate EAMT. The data of patients admitted to the ICU units due to sepsis or septic shock in two tertiary healthcare facilities in Al-Madinah Al-Munawwarah were retrospectively reviewed. The current study used logistic regression analysis and artificial neural network (ANN) analysis to identify determinants of inadequate empiric antimicrobial therapy, and evaluated the performance of these two approaches in predicting the inadequacy of EAMT. The findings of this study showed that fifty-three per cent of patients received inadequate EAMT. Determinants for inadequate EAMT were APACHE II score, multidrug-resistance organism (MDRO) infections, surgical history (lower limb amputation), and comorbidity (coronary artery disease). ANN performed as well as or better than logistic regression in predicating inadequate EAMT, as the receiver operating characteristic area under the curve (ROC-AUC) of the ANN model was higher when compared with the logistic regression model (LRM): 0.895 vs. 0.854. In addition, the ANN model performed better than LRM in predicting inadequate EAMT in terms of classification accuracy. In addition, ANN analysis revealed that the most important determinants of EAMT adequacy were the APACHE II score and MDRO. In conclusion, more than half of the patients received inadequate EAMT. Determinants of inadequate EAMT were APACHE II score, MDRO infections, comorbidity, and surgical history. This provides valuable inputs to improve the prescription of empiric antimicrobials in Saudi Arabia going forward. In addition, our study demonstrated the potential utility of applying artificial neural network analysis in the prediction of outcomes in healthcare research.

Predictive model of recurrent ischemic stroke: model development from real-world data.

Background: There are established correlations between risk factors and ischemic stroke (IS) recurrence; however, does the hazard of recurrent IS change over time? What is the predicted baseline hazard of recurrent IS if there is no influence of variable predictors? This study aimed to quantify the hazard of recurrent IS when the variable predictors were set to zero and quantify the secondary prevention influence on the hazard of recurrent ischemic stroke. Methods: In the population cohort involved in this study, data were extracted from 7,697 patients with a history of first IS attack registered with the National Neurology Registry of Malaysia from 2009 to 2016. A time-to-recurrent IS model was developed using NONMEM version 7.5. Three baseline hazard models were fitted into the data. The best model was selected using maximum likelihood estimation, clinical plausibility, and visual predictive checks. Results: Within the maximum 7.37 years of follow-up, 333 (4.32%) patients had at least one incident of recurrent IS. The data were well described by the Gompertz hazard model. Within the first 6 months after the index IS, the hazard of recurrent IS was predicted to be 0.238, and 6 months after the index attack, it reduced to 0.001. The presence of typical risk factors such as hyperlipidemia [HR, 2.22 (95%CI: 1.81-2.72)], hypertension [HR, 2.03 (95%CI: 1.52-2.71)], and ischemic heart disease [HR, 2.10 (95%CI: 1.64-2.69)] accelerated the hazard of recurrent IS, but receiving antiplatelets (APLTs) upon stroke decreased this hazard [HR, 0.59 (95%CI: 0.79-0.44)]. Conclusion: The hazard of recurrent IS magnitude differs during different time intervals based on the concomitant risk factors and secondary prevention.

Antibiotic Overprescribing among Neonates and Children Hospitalized with COVID-19 in Pakistan and the Implications.

There are concerns with excessive antibiotic prescribing among patients admitted to hospital with COVID-19, increasing antimicrobial resistance (AMR). Most studies have been conducted in adults with limited data on neonates and children, including in Pakistan. A retrospective study was conducted among four referral/tertiary care hospitals, including the clinical manifestations, laboratory findings, the prevalence of bacterial co-infections or secondary bacterial infections and antibiotics prescribed among neonates and children hospitalized due to COVID-19. Among 1237 neonates and children, 511 were admitted to the COVID-19 wards and 433 were finally included in the study. The majority of admitted children were COVID-19-positive (85.9%) with severe COVID-19 (38.2%), and 37.4% were admitted to the ICU. The prevalence of bacterial co-infections or secondary bacterial infections was 3.7%; however, 85.5% were prescribed antibiotics during their hospital stay (average 1.70 ± 0.98 antibiotics per patient). Further, 54.3% were prescribed two antibiotics via the parenteral route (75.5%) for ≤5 days (57.5), with most being 'Watch' antibiotics (80.4%). Increased antibiotic prescribing was reported among patients requiring mechanical ventilation and high WBCs, CRP, D-dimer and ferritin levels (p < 0.001). Increased COVID-19 severity, length of stay and hospital setting were significantly associated with antibiotic prescribing (p < 0.001). Excessive antibiotic prescribing among hospitalized neonates and children, despite very low bacterial co-infections or secondary bacterial infections, requires urgent attention to reduce AMR.

Pharmacometric modeling of drug adverse effects: an application of mixture models in schizophrenia spectrum disorder patients treated with clozapine.

Clozapine has superior efficacy to other antipsychotics yet is underutilized due to its adverse effects, such as neutropenia, weight gain, and tachycardia. The current investigation aimed to introduce a pharmacometric approach to simultaneously model drug adverse effects, with examples from schizophrenia spectrum patients receiving clozapine. The adverse drug effects were represented as a function of time by incorporating a mixture model to describe individual susceptibility to the adverse effects. Applications of the proposed method were presented by analyzing retrospective data from patients' medical records in Psychiatric Clinic, Penang General Hospital. Tachycardia, weight gain, and absolute neutrophils count (ANC) decrease were best described by an offset, a piecewise linear, and a transient surge function, respectively. 42.9% of the patients had all the adverse effects, including weight gain (0.01 kg/m2 increase every week over a baseline of 24.7 kg/m2 until stabilizing at 279 weeks), ANC decrease (20% decrease from 4540 cells/µL week 12-20.8), and tachycardia (14% constant increase over a baseline of 87.9 bpm for a clozapine maintenance dose of 450 mg daily). 32.5% of the patients had only tachycardia, while the remaining 24.6% had none of the adverse effects. A new pharmacometric approach was proposed to describe adverse drug effects with examples of clozapine-induced weight gain, ANC drop, and tachycardia. The current approach described the longitudinal time changes of continuous data while assessing patient susceptibility. Furthermore, the model revealed the possible co-existence of ANC drop and weight gain; thus, neutrophil monitoring might predict future changes in body weight.

Patterns of dyslipidemia and its associated factors among prediabetic subjects. A cross-sectional study at a primary care clinic.

Introduction: Diabetes is closely linked to cardiovascular diseases, with diabetic dyslipidaemia serving as an established marker of the acceleration of complications, contributing to an increased cardiovascular risk among patients. Timely detection and early characterization of lipid abnormalities can help clinicians in implementing effective preventive measures. This study aimed to determine the patterns and associated factors of dyslipidaemia among Malaysian subjects with borderline diabetes. Methods: A retrospective study was conducted among subjects with borderline diabetes aged ≥18 years who visited a primary healthcare centre at Universiti Sains Malaysia from January 2017 to December 2018. Sociodemographic, clinical and laboratory data were obtained from electronic medical records. Data were analysed using SPSS version 25. Results: A total of 250 participants with borderline diabetes were included in the analysis. Of them, 93.6% (n=234) had lipid abnormalities. Isolated dyslipidaemia characterised by a high low-density lipoprotein cholesterol (LDL-C) level (38.8%, n=97) was the most common pattern found, followed by combined dyslipidaemia of high LDL-C and triglyceride (TG) levels (22.8%, n=57). The male sex was found to be significantly associated with hypertriglyceridemia (adjusted odds ratio [AOR] = 1.86, 95% confidence interval [CI] =1.09-3.1)(P=0.02). Diastolic blood pressure ≥90mmHg was significantly associated with a low HDL-C level (A0R=2.09, 95% CI=1.0-4.1) (P=0.03). Conclusion: The majority of subjects with borderline diabetes have lipid abnormalities. Specifically, isolated dyslipidaemia characterised by a high LDL-C level is alarmingly prevalent. Further large-scale robust studies are needed to confirm the present findings.

Treatments and Predictors of Mortality for Carbapenem-Resistant Gram-Negative Bacilli Infections in Malaysia: A Retrospective Cohort Study.

This study evaluated the treatments, mortality rate and patient-related factors associated with mortality. This is a retrospective study involving hospitalised patients with infections caused by carbapenem-resistant Gram-negative bacilli (CR-GNB) in a tertiary hospital in Malaysia from January 2018 to June 2020. A clinical pharmacist reviewed patients' electronic records and collected the data according to a pre-designed form. Data were analysed using both descriptive and inferential tests. The study included 145 patients with CR-GNB infections including 77, 40 and 28 Acinetobacter baumannii, enterobacteriaceae and Pseudomonas aeruginosa, respectively. The mean age was 57.9 ± 15.8 years. Pneumonia (40.7%) and bacteremia (25.5%) were the most common infections. Meropenem (24.7%) and piperacillin-tazobactam (20.4%) were the most commonly used empiric antibiotics while colistin (63.3%) and amikacin (8.3%) were the most common definitive antibiotics. The mean duration before active antibiotics was 4.6 ± 3.3 days. Overall, the in-hospital mortality rate was 41.4%. Multivariate logistic regression analysis showed that intensive care unit (ICU) admission (adjusted odds ratio (AOR): 5.201; 95% confidence interval (CI): 1.603-16.872; p = 0.006), sepsis/septic shock (AOR: 3.430; 95% CI: 1.021-11.522; p = 0.049) and elevated serum creatinine (AOR: 2.752; 95% CI: 1.005-7.536; p = 0.049) were independently associated with mortality. The mortality rate among patients with CR-GNB infection is high. A high rate of inappropriate antibiotic use was observed, including combination antibiotic therapy and delays in starting active antibiotics. Mortality was significantly associated with ICU admission, sepsis/septic shock and elevated serum creatinine.

Survival Trend of Tuberculosis Patients and Risk Factors Associated with Mortality and Developing Drug-Resistant Tuberculosis in Hospital Pulau Pinang, Malaysia: A Retrospective Study.

BACKGROUND: Multidrug resistance TB (MDR-TB) has emerged as a public health issue worldwide, and the mortality rate is worrying. Therefore, this study was conducted to investigate the factors related to MDR-TB occurrence and the survival experience of TB patients. METHODS: A retrospective cohort study was conducted at Hospital Pulau Pinang in Malaysia. Medical records of active TB patients from 2014-2018 were reviewed. Cox regression was used to identify the factors associated with MDR-TB development and mortality among TB patients. RESULTS: The patients had a mean age of 48.84 ± 16.713 years, and a majority of the Chinese race (46.4%). Out of 351 TB patients, 325 (92.6%) were drug-susceptible TB, and 26 (7.4%) were diagnosed with MDR-TB. Among drug-susceptible TB patients, 245 (75.4%) achieved successful outcomes, and 73 (22.5%) passed away. In multivariable Cox regression, drug addiction, levels of white blood cells, urea, platelets, and albumin were significantly associated with death. Relapsed TB, alcohol consumption, and being single were significant risk factors for MDR-TB development. CONCLUSION: Patients achieved a success rate of 75.4%, which is encouraging but still far below the WHO target (at least an 85% success rate) and has room for further improvement.

Abstinence Rate, Adverse Events and Withdrawal Symptoms after Varenicline Use and Predicting Factors of Smoking Abstinence: A Multicentre Single-State Study in Malaysia.

(1) Background: Varenicline is a widely prescribed agent in smoking cessation. However, the abstinence rate, the incidence of adverse events and withdrawal symptoms, have not been widely studied locally. This study aimed to determine the prevalence of smoking abstinence, adverse events and withdrawal symptoms associated with varenicline use, as well as possible factors contributing to successful smoking abstinence. (2) Methods: This was a retrospective, cohort study conducted in twenty-two government-operated smoking cessation clinics across the state of Perak, Malaysia. The medical records of adult smokers (age ≥ 18 years old) who were prescribed with varenicline between January 2017 and June 2018 were traced. The medical records of smokers who used pharmacotherapy other than varenicline, those who received less than four weeks of varenicline treatment, and with missing data were excluded. (3) Results: Sixty-eight out of 114 subjects (59.6%) successfully achieved smoking abstinence. Probable varenicline-induced chest pain was documented in three subjects. Altered behaviour (n = 2) and auditory hallucinations (n = 1) were also reported. Varenicline treatment duration is a significant predictive factor for successful smoking abstinence (odds ratio (OR) = 2.45; 95% confidence interval (CI) 1.74−3.45; p < 0.001), followed by age (OR = 1.25; 95% CI 1.005−1.564; p = 0.045), the presence of adverse events (OR = 0.096; 95% CI 0.014−0.644; p = 0.016) and withdrawal symptoms (OR = 0.032; 95% CI 0.016−0.835; p = 0.032). (4) Conclusion: Almost two-thirds of the subjects achieved smoking abstinence with varenicline. The duration of the treatment, as well as the patients' ages had a significant influence on successful smoking abstinence. Rare cases of cardiovascular and neuropsychiatric-related adverse events were reported, warranting continuous surveillance and adverse drug reaction reporting.

COVID-19 Vaccination Hesitancy: A Review of the Literature and Recommendations.

Vaccines are important to improve immunity against pathogens and diseases. The current COVID-19 disease is rapidly evolving and spreading among people; therefore, it is important to utilize a proper vaccination strategy against it. Currently, many approved vaccines are available and accessible; however, there is a reported hesitancy against taking them among the public and even the health care workers. Mainly, this is attributed to the fear of the possible side effects and complications. Moreover, inaccurate knowledge disseminated through the media/social media especially by those who lack proper expertise adds confusion and more fear that affects the vaccination decision. For such reasons, it is essential to find strategies to increase the acceptability of vaccines and to enhance confidence in the vaccination process. This should be accompanied by sufficient efforts and proper clinical studies to confirm the value and the safety of the vaccines. Those strategies are important to avoid the further spread of the COVID-19 disease and to abort the pandemic worldwide, especially when considering the likely approach towards a COVID-19 booster vaccination program, in which booster vaccines are re-taken along intervals to adequately contain the rapidly evolving nature of the virus. This review article highlights the factors influencing the acceptability of the COVID-19 vaccination and enrollment in clinical trials among the public and some specific populations. Furthermore, it summarizes the suggested strategies and recommendations that can improve the attitudes towards COVID-19 vaccination programs.

Population pharmacokinetics analyses of rifampicin in adult and children populations: A systematic review.

AIMS: Rifampicin has become an essential component as the first-line therapy for pulmonary tuberculosis (PTB). Several population pharmacokinetic (PK) studies on rifampicin in adult and child populations have been studied previously, therefore the aims of the systematic review were (i) to summarize the relevant published studies and significant covariates that influence the PK of rifampicin across different populations, and (ii) to identify any knowledge gap that requires additional research in the future. METHODS: A total of 121 relevant population PK articles were systematically identified using PubMed and Scopus from inception to October 2021. Review articles, in-vitro and physiological methods, animal studies and noncompartmental analysis were excluded. RESULTS: Nineteen studies, of which 16 involved adults, two involved children, and one involved both adults and children, were included in the review. The structural model of rifampicin can be described as one compartment with a transient compartment absorption model and first-order elimination in most of the studies. Pharmaceutical formulation, body weight, gender, pregnancy status, diabetes and nutritional supplementation were found to be the significant covariates that affect the PK parameters. External validation of the developed PK model was only conducted in two studies. CONCLUSIONS: The source of variability for PK parameters of rifampicin remains inconsistent and poorly understood even though there were many potential covariates investigated in the selected studies. Exploring other possible factors and implementing a strict sampling strategy by considering the induction effects might uncover precise and reliable information. Furthermore, external validation should be frequently conducted to produce better predictability of model performance.

Health-related quality of life and its association with sociodemographic, economic, health status and lifestyles among HIV-positive patients in northern Malaysia.

Sociodemographic status and medical problems were widely reported as the major factors in people living with HIV (PLHIV) with lower health-related quality of life (HRQoL). However, lifestyles and cultural changes are rarely studied. A multicentred cross-sectional study was conducted among 137 virally suppressed PLHIV on antiretroviral therapy (ART) in northern Malaysia by face-to-face interviews and World Health Organization Quality of Life (WHOQOL)-BREF questionnaire. It was to explore their health and socioeconomic status, lifestyles, and associations with different HRQoL domains. The result of multiple linear regression showed that smoking was a predominant risk factor of lower physical (beta coefficient (ß): -5.82, 95% confidence interval (CI): -9.97 to -1.66; p = 0.006), social (ß: -8.76, 95% CI: -15.12 to -2.40; p = 0.007), and environmental domain scores (ß: -10.25, 95% CI: -15.21 to -5.30; p < 0.001). Poor physical health also associated with unemployment (p < 0.001) and adverse drug reaction (p = 0.015). Ethnicity was a significant factor of psychological (p = 0.007) and environment domain score (p = 0.009). HRQoL of PLHIV is strongly associated with their lifestyles and societal class. Mandatory lifestyle screening, behavioural interventions and re-employment assistance should be implemented on all PLHIV.

Time-Dissociated Pharmacokinetic Pharmacodynamic Model of Cyclosporine Among Malaysian Renal Transplant Recipients.

BACKGROUND: Cyclosporine is an essential component of many immunosuppressive regimens. However, its pharmacokinetic and pharmacodynamic (PKPD) modeling has not been widely investigated. This study aims to develop a time-dissociated PKPD model of cyclosporine in renal transplant patients. METHODS: Medical records of renal transplant patients at Penang General Hospital were retrospectively analyzed. A time-dissociated PKPD model with covariate effects was developed using NONMEM to evaluate renal graft function response, quantified as estimated glomerular filtration rate (eGFR), toward the cyclosporine cumulative exposure (area under the concentration-time curve). The final model was integrated into a tool to predict the potential outcome. Individual eGFR predictions were evaluated based on the clinical response recorded as acute rejection/nephrotoxicity events. RESULTS: A total of 1256 eGFR readings with 2473 drug concentrations were obtained from 107 renal transplant patients receiving cyclosporine. An Emax drug effect with a linear drug toxicity model best described the data. The baseline renal graft level (E0), maximum effect (Emax), area under the concentration-time curve achieving 50% of the maximum effect, and nephrotoxicity slope were estimated as 12.9 mL·min-1·1.73 m-2, 50.7 mL·min-1·1.73 m-2, 1740 ng·h·mL-1, and 0.00033, respectively. The hemoglobin level was identified as a significant covariate affecting the E0. The model discerned acute rejection from nephrotoxicity in 19/24 cases. CONCLUSIONS: A time-dissociated PKPD model successfully described a large number of observations and was used to develop an online tool to predict renal graft response. This may help discern early rejection from nephrotoxicity, especially for patients unwilling to undergo a biopsy or those waiting for biopsy results.

A Repeated Time-to-Positive Symptoms Improvement among Malaysian Patients with Schizophrenia Spectrum Disorders Treated with Clozapine.

Clozapine remains the drug of choice for resistant schizophrenia. However, its dose-response relationship is still controversial. The current investigation aimed to develop a repeated time-to-positive symptoms improvement following the onset of clozapine treatment in Malaysian schizophrenia spectrum disorder patients. Data from patients' medical records in the Psychiatric Clinic, Penang General Hospital, were retrospectively analyzed. Several parametric survival models were evaluated using nonlinear mixed-effect modeling software (NONMEM 7.3.0). Kaplan-Meier-visual predictive check (KM-VPC) and sampling-importance resampling (SIR) methods were used to validate the final model. A total of 116 patients were included in the study, with a mean follow-up of 306 weeks. Weibull hazard function best fitted the data. The hazard of positive symptoms improvement decreased 4% for every one-year increase in age over the median of 41 years (adjusted hazard ratio (aHR), 0.96; 95% confidence intervals (95% CI), (0.93-0.98)). However, patients receiving a second atypical antipsychotic agent had four-folds higher hazard (aHR, 4.01; 95% CI, (1.97-7.17)). The hazard increased 2% (aHR, 1.02; 95% CI, (1.01-1.03)) for every 1 g increase in the clozapine six months cumulative dose over the median of 34 g. The developed model provides essential information on the hazard of positive symptoms improvement after the first clozapine dose administration, including modifiable predictors of high clinical importance.

Assessment of risk factors responsible for rapid deterioration of lung function over a period of one year in patients with chronic obstructive pulmonary disease.

Compromised lung function is a common feature of COPD patients, but certain factors increase the rate of lung function decline in COPD patients. The objective of the current study was to investigate the effect of different clinically important factors responsible for rapid deterioration of lung function quantified as ≥ 60 ml decline in FEV1 over a period of one year. COPD patients recruited from the chest clinic of Penang hospital were followed-up for one year from August 2018 to August 2019. Rapid deterioration of lung function was defined as greater than 60 ml/year decline in force expiratory volume in one second. Among 367 included patients 73.84% were male, with mean age 65.26 (9.6) years and % predicted FEV1 51.07 (11.84). 30.27% patients showed mean decline of ≥ 60 ml in FEV1. The regression analysis showed that current smoking relative risk (RR) = 2.38 (1.78-3.07), p < 0.001); GOLD Stage III& IV RR = 1.43 (1.27-1.97), p < 0.001); mMRC score 3 to 4 RR = 2.03 (1.74-2.70), p < 0.01); SGRQ-C score ≥ 10 points difference RR = 2.01 (1.58-2.73), p < 0.01); SGRQ-C symptoms Score ≥ 10 points difference RR = 1.48 (1.23-2.29), p < 0.001); 6MWT < 350 m RR = 2.29 (1.87-3.34), p < 0.01); ≥ 3 exacerbation in study year RR = 2.28 (1.58-2.42, p < 0.001); 8 or more hospital admission days (RR = 3.62 (2.66-4.20), p < 0.001); Charlson comorbidity index ≥ 3 RR = 3.18 (2.23-3.76), p < 0.01) and emphysema RR = 1.31 (1.15-1.79), p < 0.01) were significant risk factors for the rapid deterioration of lung function (FEV1 decline ≥ 60 ml). Among different factors CCI score ≥ 3, abrupt decline in health status, exacerbation frequency ≥ 3, hospital admission days ≥ 8 and emphysema were reported as risk factors for rapid deterioration of lung function.