Pharmacogenomics (PGx) is a research area aimed at identifying genetic factors that are associated with drug responses, including drug efficacy, adverse drug reactions, and the appropriate drug dosage on a case-to-case basis. To promote the clinical implementation of PGx testing, which is currently of limited use in clinical practice, recent research has focused on providing reliable evidence for its clinical utility. In neurology, psychiatry, and neurosurgery, several human leukocyte antigen (HLA) alleles have been reportedly associated with cutaneous adverse drug reactions (cADRs) induced by antiepileptic drugs, which significantly carry the risk of developing cADRs. Prior to using antiepileptic drugs such as carbamazepine and lamotrigine, which are prone to cause severe cADRs, preemptive HLA genetic testing and therapeutic interventions such as drug selection and dosage adjustment based on the results of the tests can reduce the incidence of cADRs in the population before the initiation of treatment.