Abstract: AIM: To investigate effects of β₁-adrenergic receptor and CYP2D6 gene polymorphism on metoprolol antihypertension therapy.METHODS: 120 cases of patients with essential hypertension were detected by β₁-adrenergic receptor and CYP2D6 gene polymorphism,118 patients with Arg 389 allele in β₁- adrenergic receptor gene chosen from 120 essential hypertension patients were divided into three phenotype groups according to CYP2D6 gene mutations: the poor metabolism group(PM, 55 cases), intermediate metabolism group(IM, 36 cases)and extensive metabolism group(EM, 27 cases).The subjects of PM, IM and EM were administrated with metoprolol for the same dose(100 mg/d), taking orally twice a day. Blood pressures, heart rates and side effects were observed during 4-week following-up.RESULTS: Blood pressure and heart rate in group PM, IM and EM were decreased, especially, obviously decreased in group PM, however, the incidence of side effect was significantly increased in group PM.CONCLUSION: The genetic polymorphism of β₁- adrenergic receptor and CYP2D6 was associated with the efficiency of metoprolol antihypertension therapy.

Key words: Essential hypertension, β₁-adrenergic receptor, CYP2D6, Genetic polymorphism, Metoprolol