Title:Patient, Disease, and Drug-Related Risk Factors Associated with Phenytoin-
Induced Cutaneous Adverse Drug Reactions in South Indian Epileptic
Patients - A Prospective Case-Control Study
Volume: 17
Issue: 3
Author(s): Shobana John, Bhutorn Canyuk, T.C. Vijay Anand, Chonlaphat Sukasem and Sutthiporn Pattharachayakul*
Affiliation:
- Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Songkhla, Hat
Yai-90110, Thailand
Keywords:
Cutaneous Adverse Drug Reactions (CADRs), AEDs, Phenytoin (PHT), risk factors, epileptic patients, gene mutations.
Abstract:
Background: Phenytoin is the most commonly reported aromatic Anti-Epileptic Drug
(AED) to cause Cutaneous Adverse Drug Reactions (CADRs). Cutaneous adverse drug reactions
may be immune or non-immune mediated. It has been observed that predisposition is multifactorial
and that gene mutations alone cannot be the cause.
Objectives: In this study, we investigated the patient, disease, and drug-related risk factors associated
with phenytoin-induced cutaneous adverse drug reactions in South Indian epileptic patients.
Methods: This study was conducted as a single-center prospective case-control study over a period
of 13 months. The Fisher’s exact test and multivariate binary logistic regression analysis were used
to test the association of single and multiple variables, respectively.
Results: This study comprised 26 patients with phenytoin-induced cutaneous adverse drug reactions
(PHT-CARDs) and 32 phenytoin-tolerant controls with a mean age of 40.60±18.15 and
36.21±14.71 years, respectively. Among 26 phenytoin-induced cutaneous adverse drug reactions,
76.92% cases were mild-moderate reactions and 23.07% were severe. The onset latency period of
these reactions ranged from 7-42 days. The multivariate analysis showed that multiple AEDs (OR
=18.62, 95% CI 4.28-80.87, p=< .001) and comorbidities (OR= 5.98, 95% CI 1.33-26.78, p=.01)
are risk factors for PHT-CADRs. PHT-SCARs were shown to be associated with previous allergy
history (OR= 31, % CI 2.40-398.8, p=.008).
Conclusion: The risk factors found to be associated with CARDs in South Indian Epileptic patients
are multiple AEDs, comorbidities, and past allergic history. Therefore, physicians and other
associated health care professionals should closely monitor the patients when phenytoin is employed.
