THE ROLE OF PHARMACOGENETIC TESTING IN IMPROVING THE EFFICACY AND SAFETY OF ANTIPSYCHOTIC THERAPY (CASE REPORT)

Schizophrenia is a socially significant disease that requires long-term therapy with antipsychotics. In this sense, the selection of treatment that takes into account both efficacy and safety for the patient becomes critically important. Adverse drug reactions often have a genetic predisposition and are caused by the polymorphism of genes responsible for encoding proteins involved in the metabolism and transport of antipsychotics and their metabolites. Taking into account the individual pharmacogenetic characteristics of the patient, it is possible to significantly reduce the probability of adverse drug reactions. In the described clinical case of a 33-year-old patient with paranoid schizophrenia, insufficient efficacy and poor tolerability of second and third-generation antipsychotics were observed. Pharmacogenetic tests revealed that the patient was a homozygous carrier of the non-functional T alleles rs1045642, rs1128503, rs2032582 of the ABCB1 gene encoding the p-glycoprotein protein that transports antipsychotics across the blood-brain barrier, and that she was a heterozygous carrier of the non-functional A allele rs3892097 of the CYP2D6 gene encoding the 2D6 cytochrome р450 isoenzyme that metabolizes a large number of antipsychotics. The patient's pharmacogenetic phenotype was established for the first time: intermediate metabolizer and poor transporter. For further therapy of the mental disorder, the patient was prescribed the antipsychotic brexpiprazole, which is not a substrate and does not have the properties of a p-glycoprotein inhibitor. This resulted in a reduction in adverse drug reactions and a significant improvement in the patient's mental state. This clinical case emphasizes that the widespread use of pharmacogenetic testing and a personalized approach to psychopharmacotherapy can significantly improve both the efficacy and safety of antipsychotic therapy in psychiatric practice.