OBJECTIVE: The aim of this study was to compare, in normotensive postmenopausal women, the effects of drospirenone/estradiol and norethisterone acetate/estradiol on blood pressure and other surrogate markers of cerebrovascular and cardiovascular risk. METHODS: Thirty postmenopausal women were submitted to utero-ovarian ultrasonography and to color Doppler evaluation of ophthalmic arteries. Ultrasonographic and Doppler analysis of brachial artery flow-mediated vasodilatation and 24-hour ambulatory blood pressure monitoring were performed. Plasma concentrations of nitrites/nitrates were assayed. The participants were randomly assigned to drospirenone 2 mg/estradiol 1 mg (group 1; n = 15) or norethisterone acetate 0.5 mg/estradiol 1 mg (group 2; n = 15) treatment. The duration of the study was 6 months. RESULTS: The basal pulsatility index and the back pressure of the ophthalmic artery were similar in groups 1 and 2. After 6 months, no changes were observed. The nitrites/nitrates values were not different between groups 1 and 2 both in basal conditions and after therapy. The brachial artery flow-mediated vasodilatation and the pulsatility index of the brachial artery did not show any difference in groups 1 and 2 both in basal conditions and after the therapy. The 24-hour blood pressure monitoring showed no significant differences in the 24-hour time, daytime, and nighttime values either in basal conditions or after therapy. All participants were found to be dippers normally (nocturnal reduction > or =10% in comparison with diurnal values). The wake-up blood pressure values were similar in the studied participants. CONCLUSIONS: A 6-month hormone therapy with drospirenone/estradiol or norethisterone acetate/estradiol is equally effective and does not seem to alter the surrogate markers of cardiovascular and cerebrovascular risk.