Beyond acid suppression: new pharmacologic approaches for treatment of GERD.
Proton pump inhibitors are highly successful in treating gastroesophageal reflux disease, but a significant proportion of patients have persistent symptoms from weakly or nonacidic reflux. Transient lower esophageal sphincter relaxation (TLESR) represents the dominant mechanism of gastroesophageal reflux and has therefore become the most intensely investigated therapeutic target. The triggering of TLESR involve the vagal pathways and the gamma-aminobutyric type B (GABA(B)) and metabotropic glutamate type 5 (mGluR5) receptors. Baclofen is a GABA(B) receptor agonist that is effective in inhibiting TLESR and reducing the number of reflux episodes, but is associated with significant central nervous system (CNS) side effects. The newer GABA(B) agonists, such as AZD9343 and AZD3355, and mGluR5 antagonists, such as 2-methyl-6-(phenylethynyl)-pyridine (MPEP), have been shown in small, randomized, controlled trials to have comparable efficacy to baclofen, but possibly a more favorable CNS side effect profile. Cannibinoid agonists, such as Delta(9)-THC, have also been demonstrated to reduce TLESRs and reflux events respectively. Macrolide antibiotics (eg, erythromycin) show early promise in a select group of patients with possible reflux associated post-lung transplant problems.
Kuo
Paul
P
Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia.
Holloway
Richard H
RH
D000818:Animals; D001418:Baclofen / Q000494:pharmacology*; D063386:Cannabinoid Receptor Agonists; D004285:Dogs; D013759:Dronabinol / Q000494:pharmacology; D004917:Erythromycin / Q000494:pharmacology; D018755:GABA Agonists / Q000494:pharmacology*; D058786:GABA-B Receptor Agonists / Q000627:therapeutic use; D005764:Gastroesophageal Reflux / Q000188:drug therapy*; D005765:Gastrointestinal Agents / Q000494:pharmacology; D006801:Humans; D010721:Phosphinic Acids / Q000494:pharmacology; D011437:Propylamines / Q000494:pharmacology; D054328:Proton Pump Inhibitors / Q000627:therapeutic use*; D011725:Pyridines / Q000494:pharmacology; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors
D063386:Cannabinoid Receptor Agonists; D018755:GABA Agonists; D058786:GABA-B Receptor Agonists; C578935:GRM5 protein, human; D005765:Gastrointestinal Agents; D010721:Phosphinic Acids; D011437:Propylamines; D054328:Proton Pump Inhibitors; D011725:Pyridines; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate; C545087:lesogaberan; D004917:Erythromycin; D013759:Dronabinol; C121465:6-methyl-2-(phenylethynyl)pyridine; D001418:Baclofen