Pharmacogenetics: A Boon of Biotechnology

Generally medicines or drugs are based on the concept “one medicine fits all”. In other words medicines are given for a disease without looking into the constitution of the patient, except in some cases of allergy. However, it is now known that the response to a particular drug may differ in different patients suffering with the same disease. The study of how genetic differences of patients may influence the variability in the response to specific drugs is called as pharmacogenetics. It has been recognized that the presence or absence of response to a drug, and also its adverse side effects may sometimes to be attributed to reasons like mis- dosing, drug- drug interactions, allergy or medication error. However, it has been shown that efficacy and toxicity of many medications depend on genetic polymorphism in patients for drug metabolizing enzymes, transporters, receptors and other drug targets. These genes may also encode proteins involved in drug absorption, distribution, elimination and metabolism. Many of the genes determining the response to drug are non- disease and non- gene specific and are being studied in some detail. These studies have also shown that the drug response is polygenic in many cases, thus making their clinical study difficult. A study of these genetic polymorphisms is providing a strong scientific basis for optimizing drug therapy on the basis of each patient’s constitution. Pharmacogenetics approach will allow all such cases to be dealt more appropriately, through a study of genetic basis of patients’ response to medicines. In this review article I’ll try to collect some important views and work of different workers on the pharmacogenetics and pharmacogenomics.