An open multicentre study was conducted to evaluate the long term efficacy and tolerability of once-daily amlodipine (5 or 10mg for up to 24 weeks) in 9295 patients with mild or moderate essential hypertension. After a 2-week washout period, patients began treatment with amlodipine 5 mg/day, and this could be increased to 10 mg/day in patients showing inadequate blood pressure control after 2 weeks. If acceptable control was not achieved after 6 weeks of treatment with amlodipine alone, a second antihypertensive agent could be added (diuretic, ACE inhibitor or beta-blocker). Data were analysed for the population as a whole, as well as for 2 subgroups based on age (group I: less than or equal to 65 years; group II: > 65 years). 9295 patients were evaluable for tolerability and 8031 for efficacy. Significant reductions were achieved in both sitting and standing systolic and diastolic blood pressure after antihypertensive therapy (sitting position from 171/102mm Hg to 143/84mm Hg; standing position from 170/102mm Hg to 143/84mm Hg; p < 0.001), and successful blood pressure control was achieved in 83% of the patients treated with amlodipine alone. None of the patients experienced significant changes in heart rate, ECG parameters or bodyweight. The only statistically significant changes in laboratory findings were a reduction in total cholesterol (-3%) and low density lipid (-4.4%) levels (p < 0.001). Amlodipine was well tolerated in most patients; the most common adverse events were oedema and headache. Only 3.6% of patients discontinued treatment because of adverse events. Thus, these findings indicate that amlodipine (alone or in combination with another antihypertensive agent)is an effective and well tolerated treatment option for mild to moderate hypertension. In addition, the once-daily dosage regimen appears to have a positive influence on patient compliance, which is reflected in the high percentage of patients (86.4%) completing this trial.
