Among depressed patients, escitalopram plasma levels differed between those who were considered extensive metabolizers and inadequate metabolizers of CYP2C19.Consequently, we studied the impact of CYP2C19 gene variants on the levels of drugs in the bloodstream of individuals suffering from MDD (Major Depressive Disorder) in south India.Heterocyclic-based drugs have strong bioactivities and are active pharmacophores, used to design several drugs.A total of 109 individuals with MDD who prescribed escitalopram at doses of were 5, 10, 15, or 20 mg daily participated in this research.High-performance liquid chromatog. (HPLC) was used to analyze the level of escitalopram in blood.The polymorphisms of the CYP2C19 were determined by employing the PCR techniques.The mol. docking anal. of escitalopram against different proteins responsible for SIRT6 (PDB ID: 5Y2F), OSR1 kinase (PDB ID: 2VWI), Akt1 (PDB ID: 7APJ) & desvenlafaxine (PDB ID: 4MMC) is discussed.Our study found that 55 % of the subjects were intermediate metabolizers, followed by extensive (19.3 %), poor (17.4 %), and ultra-rapid (8.3 %).A significant correlation is identified between the steady state plasma concentration and Sex with (P- Value <0.05), and an insignificant correlation was seen in Age and BMI with (P - Value >0.05).Most gene variants seen in the study population were CYP2C19*1/*2, accounting for 49 individuals (44.9 %).Many heterocyclic-based derivatives show residual interactions, affinity, and hydrogen bonding with the different proteins with escitalopram, which were identified by investigating such heterocyclic compounds in silico mol. docking anal.The research presented here showed that heterocyclic derivatives may operate as potent anti-ischemic agents when combined with other compounds to produce highly efficient anti-ischemic agents.These findings showed that sex substantially impacted the CYP2C19 genetic variation.Medication administration to individuals with CYP2C19 PM (poor metabolizers) requires special caution.