A non-comparative open clinical pharmacological surveillance study was conducted, in which 427 patients from both sexes with diagnosis of light to moderate essential arterial hypertension were included. All patients were treated with nitrenpine, a dihydropyridinic calcium antagonist during a 28-week period. The initial dosage was 10 mg/day, increasing such dosage to 20 and 40 mg/day and associating it with a thiazidic diuretic in those patients showing no antihypertensive response (diastolic arterial pressure (DAP) of 90 mmHg or a reduction of 10 mmHg in baseline figures). A significant decrease was observed in systolic arterial pressure (from 159.3 +/- 12.6 to 149.2 +/- 12.2 mmHg) and in Dap (from 94.8 +/- 9.6 to 86.7 +/- 10.5 mmHg), p < 0.001, with effectivity in 66.3% of patients (65% receiving monotherapy; 10.3% combined therapy: nitrendipine and diuretic). No modifications were observed in heart rate nor in the biological-metabolic parameters under study. Side effects had a low incidence (15.9% of patients, with a 4.7% of drop-outs) and were well-tolerated in most cases. Given these results, we can conclude that nitrendipine is an effective and safe drug for the treatment of light to moderate arterial hypertension.