The Efficacy of Lansoprazole and Domperidone Combination on Intragastric and Intraesophageal Acidity

Inclusion Criteria: * Diagnosis of GERD with symptoms (i.e. regurgitation, pyrosis) during last one year with at least 1 or more episodes a week * Age ≥ 18 years and \<65 years * Helicobacter pylori (an infection) negative * Have a body mass index (BMI) between 18 and 33 kg/m² * pH\>4 gastric exposure \<25% on a 24-hour dual pH channel monitoring study performed prior to screening (normal intragastric pH +2SD) * Pathologic intraesophageal acidity exposure (DeMeester score \>14.75 and/or \>4% of pH\<4 (at least 21 hours measured) Exclusion Criteria: * Have food existence at stomach during upper GIS endoscopy, Barrett's stricture, GIS bleeding, malignite, and all type of GIS pathology to affects the study * Have allergy to the study drug or any of the excipients of the formulation * Must use of pain relieving medications (NSAIDs) during study, (paracetamol not excess of 2 gram/day can be used) * Use of any concomitant therapy which are drug affects the motility of GIS and acid secretion * Use of prostaglandin analogs and sucralfate * Have taken PPIs or H2-blockers within 7 days and prokinetic drugs within 3 days before entering the study * History of surgery of cholecystectomy * Abusing drugs or alcohol * Have a major psychiatric disease * Use of antidepressant (patient with minor depression or under controlled with drug can be included) * Have suppressed immune system or taken a immunosupressive treatment, including cortisone. * Have malabsorption, gastric outlet obstruction that affects the absorption of drug * Must use of drug ketoconazole, iron salts, digoxin, ampicilin esters , anticoagulants, antineoplastic agents * Women who are pregnant or of childbearing * Have gastroparesis * Current or a history of cancer, with the exception of fully excised skin carcinoma (Malign Melanoma will be excluded). * Have severe concomitant disease (i.e. uncontrolled or insuline dependent diabetes mellitus, symptomatic bladder stone (patients have asemptomatic, not undergone colesistit, stone \<3cm and polib \<1cm can be included), active or unhealed gastric or duodenum ulcer, Zollinger Ellison syndrome, primary esophageal motility disorder, pancreatitis, inflammatory bowel disease, chronic hepatic disease, severe lung disease, uncontrolled kidney failure, cardiac failure, cerebrovascular disease, epilepsy) which affects the conduct and result of study.