Hello, thanks for asking your question.
I am not aware that a PPI can suddenly stop working. how
ever, there are cases where GERD are refractory to optimal PPI treatment. For intance, GERD can "breakthrough" optimal PPI therapy. Up to 70 percent of
patients taking PPIs twice daily will have periods of
gastric pH <4 lasting for more than 60 minutes, particularly at night. Nocturnal acid breakthrough may be responsible for the majority of
patients with refractory GERD.