What is the maximum duration a patient can be on Fosamax (alendronate)?

Maximum Duration for Fosamax (Alendronate) Therapy

Patients should be treated with alendronate for 5 years, after which therapy should be reassessed and a drug holiday considered for those at low fracture risk. 1

Initial Treatment Duration

• The American College of Physicians recommends treating osteoporotic women with pharmacologic therapy for 5 years. 1
• The FDA label states that the optimal duration of use has not been determined, but safety and effectiveness data are based on clinical trials of four years duration. 2
• All patients on bisphosphonate therapy should have the need for continued therapy re-evaluated on a periodic basis, with patients at low-risk for fracture considered for drug discontinuation after 3 to 5 years of use. 2

Evidence Supporting the 5-Year Duration

• Data from the Fracture Intervention Trial Long-Term Extension (FLEX) study demonstrate that fracture protection exists for up to 5 more years after stopping alendronate in women who took it for 5 years. 1
• The American Geriatrics Society notes that women with osteoporosis taking alendronate for longer than 5 years who discontinued it for 5 subsequent years had a modest absolute increase in clinical vertebral fractures (5.3% vs 2.4%) but no difference in morphometric vertebral fractures or non-vertebral fractures. 1
• Bisphosphonates persist within bone after administration is stopped, providing continued benefit. 1

Drug Holiday Recommendations After 5 Years

For patients who have been on alendronate for 5 years, discontinuation should be considered in those at low fracture risk. 3

Criteria for Drug Holiday:

• Patient has not experienced fractures before or during therapy 3
• Fracture risk is low (femoral neck T-score > -2.5) 3, 4
• No prevalent vertebral fractures 4

Duration of Drug Holiday:

• 3 to 5 years is suggested for alendronate 3
• After this time, the patient should be reassessed 3

When to Continue Beyond 5 Years

High-risk patients should continue therapy beyond 5 years. 4

High-Risk Criteria Requiring Continuation:

• Femoral neck T-score ≤ -2.5 after 5 years of treatment 3, 4
• Prevalent vertebral fractures 4
• New fracture experienced during therapy 3
• Increased fracture risk on reassessment 3

Monitoring During and After Treatment

• Bone mineral density with vertebral fracture assessment should be performed every 1-2 years during treatment 5, 6
• Reassessment after 3-5 years of therapy should determine the need for continuation 7
• Patients who discontinue therapy should have their fracture risk re-evaluated periodically 2

Maximum Duration Considerations

• Administration of alendronate for more than 5 years has not been extensively evaluated in adjuvant trials, and therefore recommendations for longer duration are not strongly supported. 1
• Treatment with alendronate for 10 years was shown to be well tolerated with positive impact on bone density versus placebo, but concerns about rare adverse effects (atypical femoral fractures, osteonecrosis of the jaw) increase with duration beyond 5 years. 1
• There are concerns about adverse effects such as atypical bone fractures based on reports from the osteoporosis literature, supporting treatment holidays after 3 to 5 years for patients with lower fracture risk. 1

Special Populations

• For patients on glucocorticoid therapy or with cancer treatment-induced bone loss, the same 5-year reassessment principle applies, though continued risk factors may warrant longer treatment. 5
• In elderly patients with multiple comorbidities, consideration can be given to drug holidays or dose reduction after 5 years, as fracture protection may persist for up to 5 years after stopping therapy. 5