Title
Critical analysis of the main phase III clinical trials done with risedronate

Abstract
Risedronate is a piridinil bisphosphonate (a nitrogenated bisphosphonate) with a powerful antiresortive action, it's primary action mechanism is the supression of bone remodelation, with a subsequent increase of the bone mineral density (BMD), as it tends to localize at the remove surfaces, from where it is taken by the osteoclasts and in which it induces apoptotic mechanisms by inhibition of the colesterol biosynthesis routes, interfering with GTPases and disruption of the cytoskeleton, vessicle traffic and enzimatic action, among other activities.

The phase III clinical program with daily Risedronate in postmenopause osteoporosis (treatment and prevention) includes an already large list of studies, most of which, present optimal sample sizes and designs for obtaining conclusions with good levels of evidence that avail the use of risedronate in daily clinical practice.
Among these, we will cite the VERT (Vertebral Efficacy with Risedronate Therapy)studies, and the HIP (Hip Intervention Program) studies, as the highest exponents of the efects of risedronate at two levels -spine and hip- of extreme importance, because of their frecuency and consequences in morbidity and mortality, in postmenopause osteoporosis, that are resumed, analyzed y critized in this revision.

Key words
Risedronate. Bisphosphonates. HIP. VERT. Critical Analysis.