Hi tehseen: Great question. Aclasta is the brand name for (zoledronic acid) as is Reclast. Both of these drugs are made by Novartis and are given as a once yearly infusion. Aclasta was the name given to the form used in Europe/Canada/US and Reclast is the name for the same thing in the US. Actonel is an oral med that is given daily, weekly, bimonthly or monthly. Reclast, Aclasta, Zometa, Fosamax, Boniva, and Actonel are all bisphosphonates. Below is a link from Dr. Gonter that explains the *very small* risk of osteonecrosis of the jaw associated with these types of drugs.  http://www.healthcentral.com/osteoporosis/c/73/13598/reclast-acid/?ic=4004 Trying to decide which medication to take is always difficult. Talk to your Dr about your personal medical history and see which drug might be best for you.  You may want to check with your insurance co to see what the cost may be for both of these meds to see if that helps in your decision.  Good luck with your decision.