Pharmacogenomics deals with heredity and the effect of drugs. It is a branch of science devoted to efforts of explaining variability of one another drug response, and to search for the genetic basis of such variations or differences.

Pharmacogenomics a Promising tool of Personalized Medicine:The concept of individualized Drug therapy has been a central focus in clinical pharmacology and therapeutics. In practice, there are two key elements concerning customized therapies: Choice of the dosing regimen and/or the drug itself. Both of these factors contribute to personalized medicine, despite these factors individualization depends on molecular heterogeneity in human genome, patient-to-patient and between-population differences reflects in drug effects as well as therapeutic dose requirements.

STRATEGIES FOR APPLICATIONS OF PHARMACOGENOMICS TO CUSTOMIZE THERAPY;

Interpretation of Pharmacogenetic and genomic studies Reveals Identification of an association between a clinical phenotype, such as drug response, and a genetic variant or a set of genetic variants is an increasing theme in the medical literature. Another reason may be subtle differences in patient study groups, such as ethnicity or definition of end points. Thus, similar to other diagnostic approaches, pharmacogenetic testing will be implemented only when its predictive value is established and Pharmacogenetics can provide clues for discovery of novel targets and Pharmacogenomics offers much hope for novel drug target discovery and development against infectious for practicing rational use of antimicrobial drugs. Pharmacogenomics may also breathe new life into some drugs that were abandoned during the development process,Thus genome wide studies Can help in Drug discovery and  Preclinical development .For example, development of the beta-blocker drug bucindolol (Gencaro) was stopped after two other beta-blocker drugs won FDA approval to treat heart failure. But interest in Gencaro revived after tests showed that the drug worked well in patients with two genetic variants that regulate heart function. If Gencaro is approved by the FDA, it could become the first new heart drug to require a genetic test before prescription.A pivotal aim to pharmacogenomics is to provide the clinicians with genetic tests that can be applied relatively low cost in order to predict efficacy and adverse effects. Here are the few Pharmacogenetic implications Anticoagulation ;In 2007, the FDA revised the label on the  drug warfarin (Coumadin) to explain that a person’s genetic makeup might influence response to the drug.The FDA also is considering genetic testing for another blood-thinner, clopidogrel bisulfate (Plavix), used to prevent dangerous blood clots. Researchers have found that Plavix may not work well in people with a certain genetic variant. Cancer Chemotherapy Cancer is another very active area of pharmacogenomic research. Studies have found that the chemotherapy drugs, gefitinib (Iressa) and erlotinib (Tarceva), work much better in lung cancer patients whose tumors have a certain genetic change. Psychiatric Diseases Recently, researchers identified genetic variations that influence the response of depressed people to citalopram (Celexa), which belongs to a widely used class of antidepressant drugs called selective serotonin re-uptake inhibitors (SSRIs).Here by Reaching the conclusion That Pharmacogenomics helps to optimize Therapy, Drug discovery and Preclinical development,Predicting efficacy and adverse drug reactions and even detecting unidentified rare genetic disorders.

RESOURCES:

PharmGKB ,CPIC(Clinical Pharmacogenetic Implementation Consortium), DrugBank, SCAN and PACdb ,Human cytochrome P450 databases, The Pharmacogenetic website of the US FDA

Other Resources

PGRN HUB, PGRN-PiLS, Functional Pharmacogenes, PGRN- RIKEN, PharmVar, RPGEH

BARRIERS:

The Cost Factor and Access to Genomic Technologies

One reason for slow adoption of pharmacogenetic testing is that data on cost-effectiveness are limited. This is obviously a complex issue that relates not only to the cost of genotyping . Themselves.In sofar as the monogenic variability in drug metabolism is concerned, for example, inpatients in a psychiatry unit who are at extremes for CYP2D6 expression (poor and ultrarapid metabolizers) were found to incur, on average, $4000–$6000 higher healthcare costs when treated with drugs eliminated by CYP2D6 .

Pharmacogenomic Testing at Point of Care: Technical Standards and Expectations for Diagnostic Applications

Technical barriers in pharmacogenomic research are increasingly being overcome by declining costs and increased throughput of genotyping (or gene expression) methodologies. To date, much emphasis in pharmacogenomics has been placed on SNPs and their characterisation in clinical samples. These required standards for diagnostic pharmacogenomic tests at point of care are still not within reach in many countries and genetic testing largely remains restricted to specialised research laboratories or tertiary care medical centres.