Proton-pump inhibitor therapy in patients with gastro-oesophageal reflux disease: putative mechanisms of failure.

Proton-pump inhibitor (PPI) failure in gastro-oesophageal reflux disease (GORD) patients has become the main reason for referral of these patients to gastroenterology specialists. It is estimated that 30% of GORD patients requiring a PPI once daily will experience treatment failure. Patients with non-erosive reflux disease are the most common GORD-related group in which once-daily PPI therapy fails. Various mechanisms have been suggested to underlie PPI failure in GORD patients. The most pertinent include weakly acidic reflux, duodenogastro-oesophageal reflux, visceral hyperalgesia, delayed gastric emptying, psychological co-morbidity and concomitant functional bowel disorders, as well as others. Because of the importance of PPI failure as a target for future drug development, further understanding of the most relevant underlying mechanisms is needed.