Abstract The antihypertensive effects of felodipine (10 mg in the morning) and amiloride HCl-hydrochlorothiazide (Moduretic® mite; hydrochlorothiazide 25 mg, amiloride 2.5 mg, in the morning), when used as monotherapy (34 patients) or when used as the first addition in patients inadequately controlled by a beta-blocker (combined therapy, 32 patients), were compared in controlled, double-blind, crossover studies in Thai and Chinese patients with essential hypertension. After 4 weeks of monotherapy, both felodipine and Moduretic mite significantly reduced supine and standing blood pressure (BP). The supine BP reduction was significantly greater during felodipine (24 ± 4/21 ± 2 mmHg) than Moduretic mite (18 ± 3/15 ± 2 mmHg) treatment ( P < 0.05). Significantly more patients responded (supine diastolic BP ⩽90 mmHg) to felodipine (87%) than Moduretic mite (58%) ( P < 0.05). Combined therapy, with a beta-blocker plus felodipine or Moduretic mite both resulted in a significant reduction in supine and standing BP. A significantly greater reduction in supine BP was observed after felodipine (26 ± 4/17 ± 2 mmHg) than after Moduretic mite (19 ± 3/12 ± 3 mmHg) when given as additional therapy ( P < 0.05). There were more adverse events reported during Moduretic mite than felodipine treatment. One patient was withdrawn in the Moduretic mite group because of adverse events. No clinically significant changes in blood or urine laboratory tests were detected. In conclusion, felodipine given as monotherapy or in combination with a beta-blocker was more effective than Moduretic mite in reducing BP in patients with essential hypertension.