“…3,4 At the intersection point where genetic variation shapes the individual responses to combination of food and drug, pharmacogenetics takes place. 5 The optimal drug concentration range, that is, the therapeutic range that, allows drugs to be effective while avoiding side effects, maybe narrow for some pharmacological agents, making the dosing of the pharmacological agent very precise. 5 Due to physiological changes such as partial dysfunction in kidneys, hepatic blood flow, liver function, lean body mass, or increase in body fat mass and volume of distribution, especially elderly people who take more than one drug, use complementary and alternative therapies, are at risk in terms of FDI.…”