Stop PPIs (Prevacid, Prilosec etc.)7 days before the test.
Stop Pepcid, Zantac and Axid 48 hours before the test.
You can take antacids (Tums, Maalox etc.) up to the day before the test Nothing to eat or drink 6 hours before your appointment.
You will need to return at the end of 24/48 Hours to return the pH monitor.