List of products in the National Drug Code with proprietary name . Alendronate is used to prevent and treat certain types of bone loss (osteoporosis) in adults. Osteoporosis causes bones to become thinner and break more easily. Your chance of developing osteoporosis increases as you age, after menopause, or if you are taking corticosteroid medications (such as prednisone) for a long time. This medication works by slowing bone loss. This effect helps maintain strong bones and reduce the risk of broken bones (fractures). Alendronate belongs to a class of drugs called bisphosphonates.