Bisphosphonate are a class of drugs that prevent the loss of bone mass.They are used to treat osteoporosis and related bone metabolic diseases such as paget's disiease.The more used ones are:actonel, fosamax, dridronel, reclast, (zoledronic acid) Boniva and zometa.They can be taken either daily, once a week, once a month and in persons having problem taking it orally ther is an inyectable form as well.