Material and Method: With approval of the Ethical Committee, 74 postmenopausal osteoporosis were recruited in the randomized controlled trial. Each group has taken the drug every week for 24 weeks. The serum levels of bone resorption marker (CTX) were also collected at 12, and 24 weeks after taking medicine. The adverse events and evidence of osteoporotic fracture were interviewed and evaluated at regular intervals.

Results: The percentages of serum CTX reduction were not significantly different between both drugs at 12 weeks (66.3% in Aldren 70® group and 66.6% in Fosamax® group) and also at 24 weeks (71.1% in Aldren 70® group and 62.6% in Fosamax® group). Non drug response has been revealed 20% in Aldren 70® group and 23.5% in Fosamax® group. In relation to drug disintegration time, both drugs have resulted in same prevalence of side effects to gastrointestinal system. Although, Aldren 70® group had 10.8% of upper GI side effects and Fosamax® group had only 2.7%, but there is no statistical difference between both groups. Non-adherence rate was not significantly different in both groups. However, non-adherence with once a week bisphosphonate was 17.6% in 12 weeks and 26.2% in 24 weeks after starting treatment.

Conclusion: Aldren 70® was comparable to Fosamax® in terms of efficacy in reducing serum level of bone resorption maker (serum CTX) after 12 and 24 weeks of treatment. The adverse events in both groups were in an acceptable range and had no statistical difference.

Keywords: bisphosphonates, osteoporosis, post menopause, bone marker, adherence