Abstract: AIM: To evaluate the efficacy and safety of domestic olmesartan in treatment of mild to moderate essential hypertension in comparison with Ao tan and to verify its equivalency with the original study medicine.METHODS: 57 patients with mild to moderate essential hypertension were enrolled in a randomized,double-blind, multi-center, paralleded and active-controlled trial, and were divided into olmesartan group (27 patients with domestic olmesartan 20 mg+Ao tan simulated piece 1 piece 20 mg) and Ao tan group (30 patients with Ao tan 20 mg+domestic olmesartan simulated piece 1 piece 20 mg) for a 8-week therapy. All patients were followed up every two weeks, and the efficacy and adverse effects were observed. After treatment for 2 weeks, dosages of drugs were doubled in patients with seated diastolic blood pressure≥90 mm Hg (1 mm Hg=0.133 kPa).RESULTS: Compared with those before treatment, both systolic blood pressure and diastolic blood pressure significantly decreased in domestic olmesartan group and Ao tan group 8 weeks after treatment [(22.5±9.5) mm Hg and (21.4±9.5) mmHg, respectively for systolic blood pressure (P<0.001); (16.1±5.5) mm Hg and ( 14.7±4.4) mm Hg, respectively for diastolic blood pressure (P<0.001) ], while there was no significant difference between these two groups (P>0.05). There was no significant difference in total effective rate (96.30% vs 92.60%) and incidence of adverse effect between these two groups (P>0.05) .CONCLUSION: Domestic olmesartan is very effective in treatment of mild to moderate hypertension in a daily dose of 20-40 mg with good tolerability.

Key words: Domestic olmesartan, Ao tan, Hypertension, Heart rate