Differential outcomes from metabolic ratios in the identification of CYP2D6 phenotypes--focus on venlafaxine and O-desmethylvenlafaxine.

BACKGROUND: Venlafaxine (VEN), a well accepted anti-depressant, is metabolized through the cytochrome P 450 (CYP) 2D6 isozyme to form O-desmethyvenlafaxine (ODV). Due to the involvement of CYP2D6, the formation of ODV is influenced by genetic polymorphism. We used standard tools of assessment to explore the phenotypic distribution in a retrospective manner using the pharmacokinetic (PK) data of VEN and ODV obtained from several bioavailability/bioequivalence (BA/BE) studies in healthy subjects using the reference formulation. METHODS: Four single oral dose, open-label, randomized crossover BA/BE studies of VEN (doses: 37.5-150 mg) were performed in 141 healthy subjects. Plasma samples were collected over a period 72 h post VEN administration. The samples were analyzed for VEN and ODV using a validated LC/MS/MS assay with a limit of quantification 2.073 ng/mL for VEN and 3.973 ng/mL for ODV. PK parameters (C(max), T(max), AUC (0-t), AUC(0-infinity), t(1/2)) were computed using the noncompartmental approach. AUC metabolic ratios of VEN/ODV and ODV/VEN were computed for all subjects and were subjected to normality test procedures to tease out phenotypic distribution. RESULTS: ODV/VEN and VEN/ODV AUC metabolic ratios were evaluated for standard normal distribution and outliers to determine phenotypic distribution. Use of the VEN/ODV AUC metabolic ratio, arranged in a rank order, resulted in a distribution that distinguished poor metabolizers (PM) and extensive metabolizers (EM). The application of the ODV/VEN AUC metabolic ratio showed a unique distribution that distinguished ultra metabolizers (UM) and extensive metabolizers. By using both metabolic ratios, 141 healthy subjects were classified as follows: PMs = 18, EMs = 118, UMs = 5. Regardless of the formulation or dose size used, the plasma concentration-time profiles for both VEN and ODV were distinct amongst the three phenotypes identified in this work. CONCLUSIONS: The use of VEN/ODV and ODV/VEN AUC metabolic ratios suggested quantitative differences. The data support the use of ODV/VEN but not VEN/ODV metabolic ratio for the identification of UM phenotypes of VEN. The derived metabolic ratios of ODV/VEN from this work were in line with other studies that used both phenotypic and genotypic correlation strategies for VEN.

Framework for a National STEMI Program: consensus document developed by STEMI INDIA, Cardiological Society of India and Association Physicians of India.

The health care burden of ST elevation myocardial infarction (STEMI) in India is enormous. Yet, many patients with STEMI can seldom avail timely and evidence based reperfusion treatments. This gap in care is a result of financial barriers, limited healthcare infrastructure, poor knowledge and accessibility of acute medical services for a majority of the population. Addressing some of these issues, STEMI India, a not-for-profit organization, Cardiological Society of India (CSI) and Association Physicians of India (API) have developed a protocol of "systems of care" for efficient management of STEMI, with integrated networks of facilities. Leveraging newly-developed ambulance and emergency medical services, incorporating recent state insurance schemes for vulnerable populations to broaden access, and combining innovative, "state-of-the-art" information technology platforms with existing hospital infrastructure, are the crucial aspects of this system. A pilot program was successfully employed in the state of Tamilnadu. The purpose of this article is to describe the framework and methods associated with this programme with an aim to improve delivery of reperfusion therapy for STEMI in India. This programme can serve as model STEMI systems of care for other low-and-middle income countries.

Knowledge use among occupational therapists for infant feeding assessments.

BACKGROUND: Canadian occupational therapists practice in a variety of clinical settings and use different assessment approaches. To understand best practice, this study explored therapists' knowledge use for infant feeding assessments. This was chosen as one specific area of practice to study knowledge use. PURPOSE: The purpose of this qualtitative study was to investigate what therapists assess and what procedures they use to carry out their assessments. METHOD: Semi-structured interviews were conducted with 13 therapists with experience evaluating infant feeding. A constant comparative method of data analysis was used to identify common themes. RESULTS: Three themes emerged: the value of medical information, the importance of doing by observing and the need for an adaptive trial and error approach. PRACTICE IMPLICATIONS: These findings suggest therapists' experiential knowledge shape their best practice. This study informs us about the everyday knowledge used by therapists working with infants on feeding issues and helps us to understand why assessment practices may vary amongst therapists and across clinical settings.

Protocol for a prospective, controlled study of assertive and timely reperfusion for patients with ST-segment elevation myocardial infarction in Tamil Nadu: the TN-STEMI programme.

INTRODUCTION: Over the past two decades, India has witnessed a staggering increase in the incidence and mortality of ST-elevation myocardial infarction (STEMI). Indians have higher rates of STEMI and younger populations that suffer from it when compared with developed countries. Yet, the recommended reperfusion therapy with fibrinolysis and percutaneous coronary intervention is available only to a minority of patients. This gap in care is a result of financial barriers, limited healthcare infrastructure and poor knowledge and accessibility of acute medical services for a majority of its population. METHODS AND ANALYSIS: This is a prospective, multicentre, 'pretest/post-test' quasi-experimental, community-based study. This programme will use a 'hub-and-spoke' model of an integrated healthcare network based on clusters of primary-care health clinics, small hospitals and large tertiary-care facilities. It is an 'all-comers' study which will enrol consecutive patients presenting with STEMI to the participating hospitals. The primary objectives of the study is to improve the use of reperfusion therapy and reduce the time from first medical contact to device or drug in STEMI patients; and to increase the rates of early invasive risk stratification with coronary angiography within 3-24 h of fibrinolytic therapy in eligible patients through changes in process of care. Outcomes will be measured with statistical comparison made before and after implementing the TN-STEMI programme. The estimated sample size is based on the Kovai Erode Pilot study, which provided an initial work on establishing this type of programme in South India. It will be adequately powered at 80% with a superiority margin of 10% if 36 patients are enrolled per cluster or 108 patients in three clusters. Thus, the enrolment period of 9 months will result in a sample size of 1500 patients. ETHICS: This study will be conducted in accordance with the ethical principles that have their origin in the current Declaration of Helsinki and 'ethical guidelines for biomedical research on human participants' as laid down by the Indian Council for Medical Research. All participating hospitals will still obtain local ethics committee approval of the study protocol and written informed consent will be obtained from all participants. DISSEMINATION AND RESULTS: Our findings will be reported through scientific publications, research conferences and public policy venues aimed at state and local governments in India. If successful, this model can be extended to other areas of India as well as serve as a model of STEMI systems of care for low-income and middle-income countries across the world. REGISTRATION: Trial is registered with Clinical trial registry of India, No: CTRI/2012/09/003002.