Gastroesophageal Reflux Treatment in Scleroderma

Phase 1 SSc patients who fit all inclusion and exclusion criteria will be eligible to phase 1 study for evaluation the prevalence of omeprazole resistant-GERD Inclusion criteria: 1. SSc patients aged between 18 and 65 years. 2. Clinically diagnosed as GERD and GERD-questionnaire score \>3 3. Must not receive any proton pump inhibitor (PPI) or prokinetic drug within 2 weeks before baseline evaluation Exclusion criteria: 1. Pregnancy or lactation 2. Previous history of gastroesophageal surgery or endoscopic therapy due to severe erosive esophagitis 3. Present of Barrett's esophagus 4. Bedridden and confined to no self-care 5. Evidence of active malignant disease 6. Present of uncontrolled or severe medical problems such as asthma, angina, hepatic or renal diseases 7. Present of active infection that needs systemic antibiotic 8. Allergic history of omeprazole 9. Receiving prohibit co-medications that may have drug interaction or attenuate GERD symptoms such as tetracycline, ferrous salt, digoxin, isoniacid, oral bisphosphonate Phase 2 randomized parallel study SSc patients who fit all inclusion and exclusion criteria will be eligible to phase 2 study. Inclusion criteria: 1. SSc patients who completed the phase 1 study. 2. The subjects were defined as PPI-resistance. 3. The subject must be willing to continue phase 2 study. Exclusion criteria: 1. Pregnancy 2. Present of uncontrolled or severe medical problems 3. Present of active infection 4. Allergic history of alginic acid or domperidone 5. Receiving prohibit co-medications that may have drug interaction or attenuate GERD symptoms such as tetracycline, ferrous salt, digoxin, isoniacid, oral bisphosphonate 6. Chewing difficulty