Emerging drugs for gastroesophageal reflux disease.

Proton pump inhibitors (PPIs) are very effective and safe drugs for the treatment of erosive and non-erosive gastroesophageal reflux disease (GERD). Nevertheless, a significant proportion of GERD patients (30 - 40%) continue to suffer from symptoms during PPI treatment, which has stimulated the search for better drugs. Improvement of PPI pharmacokinetics and pharmacodynamics has been the main focus of drug development in the past decade with the ultimate goal of optimizing acid inhibition. New inhibitors of the proton pump with a longer half-life, acting faster and longer, have been developed, including potassium-competitive acid blockers. Recent data, however, suggest that the therapeutic efficacy of acid suppression may have reached its maximum and other mechanisms may have to be targeted to further improve symptom control. Potential drugs interacting with different targets are reflux inhibitors such as GABA(B) receptor agonists and mGluR5 antagonists. These agents reduce the number of transient lower esophageal sphincter relaxation thereby reducing both acid and non-acid reflux. Theoretically, visceral analgesics to modulate visceral perception or even growth factors to enhance mucosal healing may be other emerging drugs to treat GERD.