Introduction: Nowadays, the first-line medications in depression include SSRIs, SNRIs, NDRIs, NaSSAs, SMSs, or a melatonin (M1/M2) receptor agonist and a 5-HT2C receptor antagonist. These drugs have quite similar antidepressant efficacy and safety profiles, but they differ in chemical structure, receptor affinity, and pharmacokinetics. Areas covered: Pharmacokinetic properties of first-line antidepressant drugs and factors influencing their pharmacokinetic processes are presented. Alterations in pharmacokinetics of newer antidepressants in special populations are summarized. In addition, the significance of therapeutic drug monitoring (TDM) and pharmacogenetic testing in dose optimization for the treatment of depressive disorders using newer antidepressants is discussed. Expert opinion: Due to the fact that 30-40% of depressive patients do not respond to the therapy and that the incidence of depression is constantly growing, the search for new more effective and safer antidepressant therapies is becoming an urgent need. More well-designed clinical studies under naturalistic conditions are needed to establish/refine therapeutic ranges for older and current state-of-the-art antidepressant drugs. The pharmacogenetic testing with concomitant application of TDM seems to be the best way for implementing personalized dosing of current state-of-the-art antidepressants metabolized by polymorphic CYPs, especially when co-administered with strong inhibitors or other substrates of CYP2D6 or CYP2C19.
Keywords: CYP2C19; CYP2D6; P-glycoprotein; TDM; antidepressants; pharmacogenetics; pharmacokinetics.