Psychiatr. praxi. 2025;26(1):19-24 | DOI: 10.36290/psy.2025.004

Pharmacogenetic testing in hospitalized psychiatric patients: benefits and interpretation importance

PharmDr. Ivana Tašková, Ph.D.1, Mgr. Nicole Šafářová1, 2, 3
1 Oddělení klinické farmacie, Psychiatrická nemocnice Bohnice, Praha
2 Národní ústav duševního zdraví, Klecany
3 3. lékařská fakulta Univerzity Karlovy, Praha

Our article aims to introduce the reader to pharmacogenetic (PGx) testing in psychiatry, where it currently represents an available and significant tool in personalized medicine. PGx testing enables the adjustment of pharmacotherapy based on patients' genetic predispositions. In psychiatry, PGx testing focuses on polymorphisms in genes responsible for drug metabolism, primarily cytochrome P450 enzymes such as CYP2C19 and CYP2D6. In clinical practice, these tests can help predict drug efficacy or toxicity, thereby improving the safety and effectiveness of pharmacotherapy. PGx testing, which was conducted at the Bohnice Psychiatric Hospital, was done on patients who exhibited signs of drug resistance, discrepancies in therapeutic drug monitoring (TDM), or significant adverse effects during therapy with standard doses. Results showed that up to 75% of the tested patients had altered function of one or both CYP isoenzymes (i. e., slow, ultra-rapid, rapid, or intermediate metabolizer phenotypes). The interpretation of PGx test results is crucial and should be performed by professionals with expertise in this field. Additionally, a thorough understanding of pharmacokinetics, as well as comprehensive patient-specific information, is required. Only under these conditions can PGx testing significantly influence the correct selection and optimal dosing of psychotropic drugs, especially those whose effectiveness depends on the patient's phenotype (e.g., risperidone, haloperidol, venlafaxine, tricyclic antidepressants, es-/citalopram, etc.). Correct interpretation of PGx results also enables medication optimization, contributing to individualized therapy. This minimizes the risk of side effects and ensures better treatment outcomes. Our article concludes with a case report illustrating a real-life situation in which PGx testing played a key role in guiding pharmacotherapy decisions.

Keywords: pharmacogenetics, phenotype, polymorphism, psychotropics, psychiatry.

Accepted: March 27, 2025; Published: April 10, 2025  Show citation

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Tašková I, Šafářová N. Pharmacogenetic testing in hospitalized psychiatric patients: benefits and interpretation importance. Psychiatr. praxi. 2025;26(1):19-24. doi: 10.36290/psy.2025.004.
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