Should Fosamax Be Stopped If No Improvement Is Seen on Follow-Up DEXA Scan?
No, Fosamax (alendronate) should not be stopped simply because follow-up DEXA shows no improvement in bone mineral density. The decision to continue or discontinue bisphosphonate therapy depends on fracture risk status, treatment duration, and whether BMD remains stable rather than showing improvement 1.
Key Decision Framework
Continue Treatment If High or Very High Fracture Risk Persists
Continue alendronate for up to 10 years if fracture risk remains high, defined as T-score ≤ -2.5, prior hip or spine fracture, or high FRAX scores (hip fracture ≥3% or major osteoporotic fracture ≥20%) 1.
Stable BMD (no decline) represents treatment success, not failure—bisphosphonates primarily prevent bone loss and reduce fracture risk through mechanisms beyond BMD improvement 2, 3.
Clinical vertebral fracture risk continues to be reduced with ongoing alendronate treatment even after 5 years, with a 55% relative risk reduction (RR 0.45,95% CI 0.24-0.85) in those who continued versus discontinued therapy 3.
Consider Bisphosphonate Holiday Only After 5 Years in Lower-Risk Patients
After 5 years of oral alendronate, consider a drug holiday only if fracture risk is no longer high (T-score > -2.5 and patient has remained fracture-free), but continue treatment for up to an additional 5 years if fracture risk remains high 1.
For very high-risk patients, consider a holiday only after 6-10 years of stability 1.
The decision to end a bisphosphonate holiday should be based on: increase in fracture risk, BMD decrease beyond the least significant change of the DEXA machine, or increase in bone turnover markers 1.
Why "No Improvement" Does Not Mean Treatment Failure
BMD Stability Is the Goal
Women who discontinued alendronate after 5 years showed moderate BMD decline (-2.4% at total hip, -3.7% at spine over 5 years) but maintained BMD levels at or above pretreatment baseline from 10 years earlier 3.
No significant difference in nonvertebral fracture risk was observed between those continuing (19%) versus discontinuing (18.9%) alendronate after 5 years, except for clinical vertebral fractures 3.
Fracture Risk Reduction Occurs Independent of BMD Changes
The proportion of treatment effect attributable to BMD increases was minimal (only 1.2-2.8%) in patients receiving alendronate, indicating that fracture risk reduction occurs through mechanisms beyond BMD improvement 4.
Bone turnover markers remain suppressed even after stopping alendronate, with residual antiresorptive effects persisting for years due to bisphosphonate retention in bone 2, 5.
Common Pitfalls to Avoid
Do Not Switch to Another Oral Bisphosphonate Based on Lack of BMD Improvement
Switching from alendronate to risedronate after "treatment failure" showed no benefit: 45.5% continued to lose bone, 30.4% maintained bone mass, and only 24.1% gained bone mass after the switch 6.
Risedronate should not be recommended in the scenario of alendronate treatment failure based on densitometric response 6.
Do Not Stop Abruptly Without Reassessing Fracture Risk
Reassess using clinical criteria: presence of new fractures, T-score trajectory, bone turnover markers, fall risk, and overall fracture probability 1.
If stopping is appropriate, monitor BMD every 1-2 years during the drug holiday and restart therapy if BMD declines beyond the least significant change or fracture risk increases 1.
Alternative Strategies If Truly Inadequate Response
Consider Switching to More Potent Agents
If recurrent fractures or continued bone loss occur despite alendronate, consider switching to more potent antiresorptives (zoledronic acid, denosumab) or anabolic agents (teriparatide, romosozumab, abaloparatide) rather than stopping treatment 2, 1.
Referral to an osteoporosis specialist should be considered when recurrent fractures or continued bone loss occur in a patient receiving therapy without obvious treatable causes 1.
Verify Treatment Adherence and Secondary Causes
Use bone turnover markers to assess compliance and efficacy: significant reductions in BTMs indicate appropriate response to antiresorptive therapy 1.
Evaluate for secondary causes of bone loss (vitamin D deficiency, hyperparathyroidism, malabsorption, medications) before attributing lack of response to medication failure 1.