Dual antiplatelet therapy of aspirin and clopidogrel is pivotal for patients undergoing percutaneous coronary intervention. However, the variable platelets reactivity response to clopidogrel may lead to outcome failure and recurrence of cardiovascular events. Although many genetic and nongenetic factors are known, great portion of clopidogrel variable platelets reactivity remain unexplained which challenges the personalization of clopidogrel therapy. Current methods for clopidogrel personalization include CYP2C19 genotyping, pharmacokinetics, and platelets function testing. However, these methods lack precise prediction of clopidogrel outcome, often leading to insufficient prediction. Pharmacometabolomics which is an approach to identify novel biomarkers of drug response or toxicity in biofluids has been investigated to predict drug response. The advantage of pharmacometabolomics is that it does not only predict the response but also provide extensive information on the metabolic pathways implicated with the response. Integrating pharmacogenetics with pharmacometabolomics can give insight on unknown genetic and nongenetic factors associated with the response. This review aimed to review the literature on factors associated with the variable platelets reactivity response to clopidogrel, as well as appraising current methods for the personalization of clopidogrel therapy. We also aimed to review the literature on using pharmacometabolomics approach to predict drug response, as well as discussing the plausibility of using it to predict clopidogrel outcome.

ObjectivesGeneric medicine prescribing has become a common practice in public hospitals. However, the trend in private medical centres seems to be different. The objective of this study was to investigate knowledge, perceptions and behavior of physicians from private medical centres in Malaysia regarding generic medicines.MethodsThis study was a cross-sectional nationwide survey targeting physicians from private medical centres in Malaysia. The survey was conducted using questionnaire having (i) background and demographic data of the physicians, volume of prescription in a day, stock of generic medicines in their hospital pharmacy etc. (ii) their knowledge about bioequivalence (iii) prescribing behavior (iv) physicians’ knowledge of quality, safety and efficacy of generic medicines, and their cost (v) perceptions of physicians towards issues pertaining to generic medicines utilization.ResultsA total of 263 questionnaires out of 735 were received, giving a response rate of 35.8%. Of the respondents, 214 (81.4%) were male and 49 (18.6%) were females. The majority of the participants were in the age range of 41–50 years and comprised 49.0% of the respondents. Only 2.3% of physicians were aware of the regulatory limits of bioequivalence standards in Malaysia. Of the respondents, 23.2% agreed that they ‘always’ write their prescriptions using originator product name whereas 50.2% do it ‘usually’. A number of significant associations were found between their knowledge, perceptions about generic medicines and their demographic characteristics.ConclusionsThe majority of the physicians from private medical centres in Malaysia had negative perceptions about safety, quality and the efficacy of generic medicines. These negative perceptions could be the cause of the limited use of generic medicines in the private medical centres. Therefore, in order to facilitate their use, it is recommended that the physicians need to be reassured and educated about the drug regulatory authority approval system of generic medicines with regard to their bioequivalence, quality, efficacy and safety. Apart from the policy on generic substitution, it would also be recommended to have a national medicine pricing policy, which controls drug prices, in both the public and private sector. These efforts are worthwhile to reduce the drug expenditure and improve the medicine affordability in Malaysia.

Clopidogrel is a widely-used antiplatelet drug. It is important for the treatment and prevention of coronary heart disease. Clopidogrel can effectively reduce platelet activity and therefore reduce stent thrombosis. However, some patients still have ischemic events despite taking the clopidogrel due to the alteration in clopidogrel metabolism attributable to various genetic and non-genetic factors. This review aims to summarise the mechanisms and causes of clopidogrel resistance (CR) and potential strategies to overcome it. This review summarised the possible effects of genetic polymorphism on CR among the Asian population, especially CYP2C19 *2 / *3 / *17, where the prevalence rate among Asians was 23.00%, 4.61%, 15.18%, respectively. The review also studied the effects of other factors and appropriate strategies used to overcome CR. Generally, CR among the Asian population was estimated at 17.2–81.6%. Therefore, our overview provides valuable insight into the causes of RC. In conclusion, understanding the prevalence of drug metabolism-related genetic polymorphism, especially CYP2C19 alleles, will enhance clinical understanding of racial differences in drug reactions, contributing to the development of personalised medicine in Asia.

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