Calcium channel blockers are increasingly used in the treatment of hypertension. Newer calcium channel blockers of the dihydropyridine group have longer elimination half-lives (t1/2) that permit once-daily dosage and are generally better tolerated than their parent compound. In this study, the efficacy and safety of lacidipine and amlodipine were compared in 65 patients with mild-to-moderate hypertension attending the hypertension outpatient clinic of a teaching hospital in a randomized double-blind cross-over trial with dose titration. Lacidipine and amlodipine both significantly reduced systolic blood pressure (SBP: by 19.2 +/- 13.5 and 22.3 +/- 15.3 mm Hg, respectively) and diastolic BP (DBP: 13.3 +/- 4.2 and 12.3 +/- 5.3 mm Hg, respectively) 24 h postdose. There were no significant differences in their antihypertensive effects. The incidence of adverse events (AE) was 3% for lacidipine and 8% for amlodipine. The incidence of withdrawal from the study due to side effects was 0% for lacidipine and 3% for amlodipine. These results suggest that lacidipine is well-tolerated, and is as effective as amlodipine as a once-daily antihypertensive agent.