The use of CYP2D6 and CYP2C19 genotyping to guide antipsychotic prescribing did not improve drug persistence in patients with schizophrenia, according to a randomized clinical trial published online in JAMA Network Open.
“These results do not support routine use of genotyping for CYP2D6 and CYP2C19 polymorphisms in patients with schizophrenia,” researchers wrote.
Because psychotropic drugs are metabolized by CYP2D6 and CYP2C19, researchers aimed to gauge whether identification of genetic polymorphisms improved antipsychotic treatment in patients with schizophrenia compared with clinically guided treatment. Antipsychotic drug persistence, or the length of time elapsed before the antipsychotic medication or dose was changed, served as a surrogate for tolerability and effectiveness in the study.
The investigation included 311 adults with schizophrenia divided into 3 intervention groups: antipsychotic treatment guided by CYP test, antipsychotic treatment guided by structured clinical monitoring with adverse effects and factors affecting compliance recorded at least quarterly, or treatment as usual. Patients were followed for 1 year.
Patients who received CYP test-guided treatment did not differ in antipsychotic drug persistence from patients who received structured clinical monitoring or patients who received treatment as usual, according to the study. Even patients with notedly reduced or fast metabolic capacity had similar results with each of the interventions, subgroup analyses showed.
“The goal of this investigator-initiated randomized clinical trial was to evaluate whether routine CYP testing can improve antipsychotic treatment in terms of tolerability and effectiveness in patients diagnosed with schizophrenia,” researchers wrote. “We found no differences between study groups in antipsychotic drug persistence, neither in the full study population nor in the subgroup of extreme metabolizers.”
Jürgens G, Andersen SE, Rasmussen HB, et al. Effect of routine cytochrome P450 2D6 and 2C19 genotyping on antipsychotic drug persistence in patients with schizophrenia: a randomized clinical trial. JAMA Network Open. 2020;3(12):e2027909.