Abstract
Phenytoin is a long-established anticonvulsant that remains in substantial use presently. Data
from Songklanagarind Hospital in 2019 reveals that 1,970 outpatient and 2,583 inpatient
prescriptions for phenytoin were dispensed. Reports from the Health Product Vigilance Center
of the Thai Food and Drug Administration in 2017 documented 1,314 cases of Stevens-Johnson
Syndrome (SJS) and 124 cases of Toxic Epidermal Necrolysis (TEN), both classified as severe
cutaneous adverse reactions (SCARs), attributed to phenytoin. Numerous studies across diverse
populations have suggested associations between various genetic polymorphisms and SCARs
induced by phenytoin. Nevertheless, no genetic markers provided a promising predictability for
these adverse drug reactions in the Thai population. Furthermore, the unique anthropological
origin of Southern Thai populations also contributes to distinct genetic characteristics which
makes the clinical implication of pharmacogenetic markers more challenging. This research
project aimed to evaluate clinical factors along with genetic markers towards a better
understanding of phenytoin-induced adverse reactions. The study consisted of two phases: the
first phase involved multidimensional data analysis of a large database from Songklanagarind
Hospital to evaluate the influence of clinical parameters in a real-world dataset. The second
phase investigated the association between these predictive outcomes and genetic markers
through a case-control association study. The combined clinical and genetic data will be used
to construct a predictive model for adverse drug reactions.
