Aistė Lengvenytė1, Robertas Strumila2, Edgaras Dlugauskas3, Algirdas Utkus4, Alvydas Navickas1
1Vilnius University Medical Faculty Psychiatric Clinic, Vilnius, Lithuania
2Vilnius University Medical Faculty, Vilnius, Lithuania
3Vilnius University Medical Faculty Neurological Clinic, Vilnius, Lithuania
4Vilnius University Medical Faculty Department of Human and Medical Genetics, Vilnius, Lithuania
Background: Finding the right medication in psychiatry can be very demanding both for the doctor and for the patient. Genetic testing is successfully applied in various medical fields. Yet clinical application in psychiatry is still awaited. Individualized treatment decisions in psychiatry may be important, since substantial part of drugs are metabolized by CYP450 enzymes. Most important of them in psychiatry are CYP2D6, CYP2C19 and CYP2C9. Genotypes that determine function of these enzymes are very polymorphic, and phenotypes are classified as poor, intermediate, normal and ultrarapid metabolizer. That can strongly contribute to personal differences in response to psychotropic drugs.
Aim of the study: Determine whether pharmacogenetic testing of CYP2D6, CYP2C19 and CYP2C9 polymorphism would have had influence on 6 patients’ treatment courses, which were unsuccessful.
Methods: Six patients that were diagnosed for treatment-resistant psychiatric disorders in Vilnius University Hospital Santariskiu Clinics Centre of Neurology, Department of Psychiatry were invited to give blood samples for genetic testing retrospectively. Patients’ CYP2C19, CYP2D6 and CYP2C9 enzymes genetic polymorphism results were compared with previous empirical pharmacological treatment courses of these patients.
Results: In four cases significant polymorphism of CYP2C19 enzyme allele was detected. In all of these cases 1*/2* genetic variant, that conditions intermediate metabolizer phenotype, was identified. In the fifth case CYP2C19 ultrarapid (1/*17) and CYP2D6 poor metabolizer (4/*5) profile was discovered. Only in one case CYP2C19 (1*/1*) variant, that conditions normal metabolizer phenotype, was detected.
Conclusions: Pharmacogenetic testing could have had influence on treatment choices for 5 out of 6 selected patients leading to less side effects and rehospitalizations. More extensive studies on pharmacologic testing that would include comparison between objective clinical efficacy of treatment, measured drug concentration in serum and genetic testing results are needed.