Actonel, which is risedronate - is prescribed for treatment and prevention of osteoporosis (post-menopausal, caused by corticosteroids), Paget disease. Risedronate binds to substance of a bone tissue, inhibits its resorption mediated by osteoclasts and reduces a bone turn (does not break process of formation of a bone). It increases the biomechanical strength and volume of bone mass. The maximum decrease in a bone turn is observed in 3-6 months, remaining at the same level during a course of treatment.