Antiepileptic drugs are among the most common causes of cutaneous adverse reactions, such as mild maculopapular eruption, hypersensitivity syndrome, Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Some recent studies have reported that the human leukocyte antigen (HLA)-B* 1502 allele is associated with an increased risk of lamotrigine (LTG)-related cutaneous reactions. Objective: the authors investigated the frequency of HLA8*1502 allele and the relation between HLA-B*1502 allele and LTG-related cutaneous reactions in Vietnamese epileptic patients. Methods: This was a cross-sectional study, including 63 epileptic patients. Thirty-eight subjects were treated with lamotrigine. The presence of HLA8* 1502 was confirmed by real-time polymerase chain reaction. Patients who had taken LTG for at least 3 months without developing cutaneous adverse reactions were considered to be LTG-tolerant. Results: Among 63 subjects (28 men, 35 women, mean age at diagnosis 18.4 +/- 12. 8 years), the frequency of HLA-B*1502 allele was 25.4 percent (16 patients). The HLA-B*1502 allele was present in 80 percent (4 of 5) of LTG-related cutaneous reactions cases but in only 9.1 percent (3 of 33) of LTG-tolerant groups. The occurrence of LTG-related cutaneous reactions associated with the presence of the HLA-B* 1502 allele (odds ratio (OR) = 40
95 percent confidence interval (CI) = 3.3 - 483.4
P = 0.004). Conclusions: This study showed a high rate of HLA-B* 1502 allele in epileptic patients in Vietnam. There was statistical relation between HLA-B*1502 and lamotrigine-related cutaneous adverse reactions. Future studies with larger sample sizes are suggested to verify the results.