Zolendronate (also known as zolendronic acid or aclasta) is the most potent medicine in the bisphosphonate class currently available. Bisphosphonates work by preventing resorption of bone by inhibiting the function of bone-dissolving cells called osteoclasts. Bisphosphonates are commonly used in the treatment of osteoporosis and paget’s disease, and are also sued for preventing some forms of cancer from spreading in bone. Zolendronate is given by an intravenous infusion (into a vein in the arm in a “drip”) over about 15 – 30 minutes and can be given each 12 – 24 months as needed for treatment of osteoporosis. Treatment of paget’s disease involves even less frequent infusions. Zolendronate increases the bone density in patients with osteoporosis, to about the same extent as other medicines such as alendronate (Fosamax), and is effective at reducing fracture rates by 35 – 70%. It also reduces bone pain in paget’s disease. Other than flu-like symptoms after the first infusion, side effects from zolendronate treatment are uncommon, and are in general no different from placebo-treated patients in randomised trials. It should be remembered that major fractures can be very serious, so this should be balanced against the small risk of ill effects from treatments. Treatment is usually accompanied by some calcium tablets and/or vitamin D tablets given at the time of the infusion, to keep blood calcium levels normal.