Introduction: Combination of clopidogrel and aspirin has been proven beneficial in treating symptomatic intracranial stenosis. The CYP2C19 polymorphism (CYP2C19*1, CYP2C19*2, CYP2C19*3, and CYP2C19*17 alleles) affects the efficacy of clopidogrel. Although epidemiologic studies of CYP2C19 polymorphism have been conducted in the Thai population, data on the frequency of allelic variants of CYP2C19 in Thai patients with symptomatic intracranial stenosis are lacking. This study aims to determine the prevalence of CYP2C19 polymorphism in patients with symptomatic intracranial stenosis.
Methods: The study included 100 Thai patients with symptomatic intracranial stenosis. Genotyping of CYP2C19 alleles (CYP2C19*1, CYP2C19*2, CYP2C19*3, and CYP2C19*17) was performed using the Real-time Polymerase Chain Reaction (rt-PCR) technique.
Results: The allele frequencies of CYP2C19*1, CYP2C19*2, CYP2C19*3, and CYP2C19*17 were 70.5%, 26%, 2.5%, and 1%, respectively. The results indicated that 53% of patients with symptomatic intracranial stenosis were normal metabolizers, while 36% were intermediate metabolizers and 10% were poor metabolizers.
Conclusion: Almost half of the Thai patients with symptomatic intracranial stenosis were intermediate or poor metabolizers. The combination of aspirin and clopidogrel might not be effective in this group of patients.
The Author(s). Published by S. Karger AG, Basel.