Because of binding avidity, these drugs are slowly
released from bone and can exert actions long after
they are discontinued. This binding avidity and
duration of effect on bone has been studied clinically
to address efficacy in fracture prevention after drug
withdrawal. With use of zoledronate or alendronate
for 3 and 5 years, respectively, the antifracture effects
are maintained for 3-5 years after the drugs have been
stopped.14,15 This has led to the concept of a “drug
holiday” to allow patients with clinically and
radiographically stable bone and with low fracture
risk to discontinue zoledronate after 3 years and
alendronate after 5 years and still maintain
antifracture efficacy temporarily thereafter.