Host: The Japanese Society of Toxicology
Name : The 51st Annual Meeting of the Japanese Society of Toxicology
Date : July 03, 2024 - July 05, 2024
Aripiprazole is an atypical antipsychotic drug whose main pharmacological effect is partial agonism of the dopamine D2 receptor. Its long-acting injection (LAI) formulation is used to treat schizophrenia and bipolar disorders. Medication adherence is often the key to preventing the recurrence of both diseases, and it has been noted that LAI formulations are more effective than oral formulations in preventing recurrence. Because the LAI formulation is initiated after appropriate dosing, and tolerability has been confirmed with the oral formulation of the same ingredient, it is usually assumed that the only major adverse event to observe is injection site reactions if there are no adverse reaction problems with the oral formulation.
Aripiprazole is mainly metabolized by the drug-metabolizing enzymes cytochrome P450 (CYP) 3A4 and CYP2D6.
The metabolic capacity of CYP2D6 varies among individuals and can be classified into three categories: extensive metabolizers (EM), where enzyme activity is normal; intermediate metabolizers (IM), where activity is moderately reduced; and poor metabolizers (PM). The percentage of IM in Japanese patients has been reported to be approximately 40%.
In this study, we report a case of drug-induced liver injury in a manic patient with bipolar disorder who was started on oral aripiprazole and switched to LAI formulation after confirming that the patient tolerated the drug. We report this case because genetic polymorphism of a drug-metabolizing enzyme may have contributed to the development of drug-induced injury in this patient.
