Prokinetics to alter the position of the gastric acid pocket in Gastro Esophageal Reflux Disease

Gastro-esophageal reflux is a common phenomenon in which gastric contents flow
back into the esophageal lumen, which can cause symptoms and/ or esophageal
damage. Most reflux episodes occur during transient relaxations of the lower
esophageal sphincter (TLESR). The rate of TLESRs is however comparable in
healthy subjects and patients with gastro-esophageal reflux disease (GERD). In
contrast, several studies agree that the risk to have acidic reflux during a
TLESR is twice as large in GERD patients compared to healthy subjects.
Esophageal acid exposure is of great importance for development of symptoms
and/or esophageal damage.
Recently our lab has shown that the main factor in this difference is the
position of the postprandial acid pocket. The acid pocket is an unbuffered pool
of acid floating on top of the meal in the proximal stomach, where it is the
most important source of refluxate. By injection of 99mTc-pertechnetate we were
able to visualize this pool of acid scintigraphically, as 99mTc-pertechnetate
is also secreted by parietal cells in the stomach.
The most important finding of the study was that in patients with a large
hiatal hernia, the acid pocket may be trapped in the hiatal sac above the
diaphragm allowing acid reflux to occur during episodes of low LES pressure.
This explains the increased risk to have acidic gastroesophageal reflux during
a TLESR, when the LES relaxes after swallowing or when LES pressure is low in
patients with a hiatal hernia.
The macrolide Azitromycin is a bacterostatic antibiotic, with gastroprokinetic
properties. Erytromycin, a comparable macrolide alters proximal gastric volume
and postprandial relaxtion time. Administration of Azitromycine in patients
after lung transplant has shown to lower the rate of reflux episodes.
Interestingly, it mainly alters the rate of acidic reflux events, suggesting
that it alters the position of the acid pocket, as macrolides have no influence
on acid secretion or TLESRs. Therefore, our aim is to show that the
administration of Azitromycin leads to an altered position of the acid pocket
scintigraphically, and it thereby changes the rate of postprandial acid reflux
episodes.

Our Objective is to show that the administration of prokinectics leads to an
altered position of the acid pocket scintigraphically, and it thereby changes
the rate of postprandial acid reflux episodes.

A double blind, placebo controlled, crossover, randomized trial.

administration of azitromycin

Scintigraphy and esophageal manometry are safe and common procedures. The
utilization of prokinetics for patients with a hiatal hernia might show
valuable. Prokinetics are safe and well tolerated, and patients with a hiatus
hernia are generally patients wiith severe GERD.