Zolendronic acid is used to treat or prevent osteoporosis. Osteoporosis is a disease which causes bones to become thin. You are at risk for osteoporosis if you are: Zolendronic acid is given as an infusion (through a vein in your arm) lasting 15 minutes. You should drink 2 glasses of fluid at least one hour before receiving your infusion. You may eat normally before your infusion. Zolendronic acid infusions are once a year. The infusion must be administered by a health care professional.