Background and objective: Hypertension is very prevalent in the Chinese population in Taiwan. Chinese people frequently experience bothersome cough when receiving angiotensin-converting enzyme (ACE) inhibitors, and angiotensin II (AT(1)) receptor antagonists are thus relatively more frequently used in this context. In this trial we studied the effectiveness of a new AT(1) receptor antagonist, olmesartan, in the treatment of Chinese patients with mild-to-moderate essential hypertension.
Patients and methods: The present study was a double-blind, randomised, multicentre trial to compare the efficacy and safety profiles of two AT(1) receptor antagonists, olmesartan and losartan, in the treatment of Chinese patients with mild-to-moderate essential hypertension. 126 adults were randomised to receive either once-daily olmesartan 20mg or once-daily losartan 50mg for 12 weeks. There were 49 evaluable patients in the olmesartan group and 57 in the losartan group.
Results: At baseline, neither diastolic (DBP) nor systolic (SBP) blood pressures were significantly different between the two study groups. Trough blood pressures were measured and recorded for the evaluation of treatment effect. After drug treatment for 4, 8 and 12 weeks, SBP and DBP values were significantly decreased in both groups of patients. However, both SBP and DBP were significantly lower in the olmesartan group than in the losartan group after treatment. At the end of treatment, DBP values were 87.0 +/- 8.6mm Hg versus 91.6 +/- 8.7mm Hg (p < 0.001) and SBP values were 129.5 +/- 12.6mm Hg versus 135.4 +/- 12.1mm Hg (p < 0.001) in the olmesartan and losartan groups, respectively. After 4 weeks of treatment, the reduction in BP values was larger in the olmesartan group than in the losartan group (decreases in DBP of 12.1 +/- 8.4mm Hg vs 7.2 +/- 6.8mm Hg [p < 0.005] and in SBP of 15.1 +/- 13.0mm Hg vs 10.3 +/- 10.1mm Hg [p < 0.05] for the olmesartan and losartan groups, respectively). Patients treated with either drug experienced only mild adverse reactions, such as dizziness, cough, headache and neck pain, all of which occurred at low frequencies. There were no significant changes in laboratory parameters.
Conclusion: Both olmesartan and losartan are effective and safe in the treatment of Chinese patients with mild-to-moderate essential hypertension. Olmesartan 20mg once daily is more potent and has a more rapid antihypertensive effect than losartan 50mg once daily in the treatment of mild-to-moderate hypertension in Chinese patients.