Aclasta (zoledronic acid)
Aclasta (zoledronic acid) is a drug used in treatment of postmenopausal osteoporosism (PMO). The regime is a yearly intravenous infusion where 100 mililitres infusion fluid containing 5 mg of zoledronic acid is given over a period of at least 15 minutes. Aclasta, which is documented with concurrent treatment with calcium and vitamin D, reduces the risk of in vertebral fractures with 70%, in non-vertebral fractures with 25% and hip fractures with 41%. All risk reductions are significant compared to placebo. In absolute numbers it is 7,6%, 2,7% and 0,9%. Aclasta causes, by first injection, in 7% of the patients a flu-like syndrome and transient hypocalcaemia, which is also known from other intravenous bisphosphates. In a study of approximately 7.700 women with PMO an increased occurrence of atria flickering was seen in the Aclasta-treated patients. The mechanism behind the increased occurrence of atria flickering is unknown. Aclasta is not metabolised and is secreted unchanged through the kidneys.
Effect and documentation are comparable to the bisphosphonates alendronate and risedronate. Aclasta is however better documented than etidronate and ibandronate in the treatment of postmenopausal osteoporosis. Because of Aclastas higher price, alendronate should be used as the first choice of treatment in patients with postmenopausal osteoporosis.