Antihypertensive agents are routinely studied in terms of changes in the level of systolic, diastolic, and mean arterial pressure. Pulse pressure may be independently modified from these parameters as a consequence of specific changes in the mechanical properties of the large arteries and in the timing of incident and reflected pressure waves. The aim of this study was to evaluate the changes in pulse pressure produced by acute calcium blockade by the dihydropiridine derivative, lacidipine, in a double-blind design versus placebo in 18 subjects with mild to moderate hypertension. Carotid and femoral pressure waveforms were recorded noninvasively by applanation tonometry using a Millar micromanometer-tipped probe. Early (Pi) and mid-to-late (Ppk) systolic peaks of carotid pressure waveform were evaluated, enabling the effect of incident pressure wave to be quantified as the ratio of Pi to the total height of carotid pulse wave (PP) (Pi/PP) and the effect of wave reflections as the ratio (Ppk-Pi)/PP. Travel time of the reflected wave (delta tp) was timed from the foot of the pressure wave to the foot of the late systolic peak. Pulsatile changes in diameter were studied using noninvasive echo-tracking techniques. Whereas mean arterial pressure significantly decreased following lacidipine, pulse pressure measured at three different sites (brachial, carotid, and femoral arteries) was unchanged. Carotid-femoral pulse wave velocity, carotid and femoral arterial stiffness, and delta tp were not modified, whereas the (Ppk-Pi)/PP ratio and left ventricular ejection time was significantly reduced and the Pi/PP ratio was significantly increased.(ABSTRACT TRUNCATED AT 250 WORDS)