Objective: To evaluate the effects of unopposed therapy (conjugated equine estrogens [CEE]) vs. opposed therapy (CEE and medroxyprogesterone acetate), tibolone, and raloxifene on serum substance p levels.
Design: Clinical study.
Setting: University hospital.
Patient(s): One hundred eight postmenopausal women were assigned to four treatment groups: unopposed hormone therapy (HT) (n = 30), opposed HT (n = 48), tibolone (n = 18), and raloxifene (n = 12).
Intervention(s): Conjugated equine estrogens, CEE and medroxyprogesterone acetate, tibolone, and raloxifene were administered orally; blood samples were collected before therapy and 3 months after.
Main outcome measure(s): Serum substance p levels were measured before and at the end of the third month of the treatment.The serum substance p levels were increased in the unopposed HT group after treatment. On the contrary, substance p levels were decreased in the opposed HT group, in the tibolone group, and in the raloxifene group.
Conclusion(s): Addition of progesterone (P) to estrogen (E) treatment significantly decreases serum substance p levels. Tibolone and raloxifene exert the same effect.