Administration of tibolone decreases 24 h heart rate but not blood pressure of post-menopausal women.
OBJECTIVE
Elevation of blood pressure and heart rate increase the risk of cardiovascular disease. Administration of estrogens does not affect heart rate but may decrease 24 h blood pressure. In this study, we tested the effect of the estro-progestogenic compound tibolone.


METHODS
Thirty healthy, post-menopausal women were randomized to receive placebo (n = 15) or tibolone, at the commonly prescribed dose of 2.5 mg per day (n = 15). Before and after 6 months of treatment, in each woman blood pressure and heart rate were monitored every 30 min for 41 h by an ambulatory device. Valuable readings were those collected from 8:00 a.m. of the second day to 8:00 a.m. of third day. Analyses were performed of 24 h, day-time (7:00 a.m.-11:00 p.m.) and night-time (11:00 p.m.-7:00 a.m.) values. Day to night difference was also calculated.


RESULTS
Placebo did not modify 24h, day-time, and night-time blood pressure or heart rate values. Day-night differences were also not affected by placebo. Similarly to placebo, tibolone administration did not modify any of the blood pressure parameters taken into consideration. By contrast, a significant decline of 24 h heart rate (73.2 +/- 2.3 beats/min versus 69.3 +/- 1.7 beats/min; P < 0.0008) was observed. The effect was significant both at day (76.6 +/- 2.4 beats/min versus 72.1 +/- 1.9 beats/min; P < 0.0001) and night (65.8 +/ 2.6 beats/min versus 62.4 +/- 1.9 beats/min; P < 0.05). Day-night blood pressure and heart rate differences were not affected by tibolone.


CONCLUSIONS
In post-menopausal women, administration of tibolone does not influence 24 h blood pressure but reduces heart rate.
Cagnacci
Angelo
A
Institute of Obstetrics and Gynecology, Policlinico di Modena, via del Pozzo 71, 41100, Italy. cagnacci@unimore.it
Baldassari
Francesco
F
Arangino
Serenella
S
Alessandrini
Chiara
C
Volpe
Annibale
A
D001794:Blood Pressure / Q000187:drug effects; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm / Q000187:drug effects; D004334:Drug Administration Schedule; D020847:Estrogen Receptor Modulators / Q000008:administration & dosage*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D020249:Hormone Replacement Therapy; D006801:Humans; D008875:Middle Aged; D009652:Norpregnenes / Q000008:administration & dosage*; D017698:Postmenopause; D016896:Treatment Outcome
D020847:Estrogen Receptor Modulators; D009652:Norpregnenes; C027385:tibolone