At the end of a short-term (3-month) study of antihypertensive treatment of mild-to-moderate hypertension, 141 of the 200 study patients continued into a 2-year follow-up of isradipine as monotherapy or in combination with other antihypertensive agents. Although all 141 patients completed the first year, only 102 completed the study. Twenty-four patients dropped out: 2 with flushing; 1 each with arrhythmia, edema, angina, and headache; 12 who were noncompliant; 2 with disease unrelated to the study drug; and 4 for reasons unknown. Before the follow-up, 70% of the 141 patients were taking isradipine; after 2 years, 63% were still taking isradipine as monotherapy. During the follow-up study, the blood pressure remained stable (142.9/86.8 mm Hg after 3 months, and 142.9/86.2 mm Hg after 2 years), whereas the normalization rate was only slightly changed (73 vs. 75.2%). The incidence of reported adverse events decreased with time. At the end of the short-term study, 44.7% of patients had reported one or more adverse events; after 2 years of treatment, only 14.4% reported adverse events. Two patients had ECG signs of left ventricular hypertrophy: one showed no relevant changes while the other presented clear signs of regression. No clinically relevant laboratory abnormalities were noted during the study. In conclusion, isradipine is effective, well tolerated and safe in the long-term treatment of mild-to-moderate hypertension.