The purpose of this study is to investigate several aspects of chronic use of acid suppressing medication: dependence on maintenance therapy, the possibilities for on-demand use, and predictors (patient characteristics) for daily need, for on-demand use and for termination of chronic use.

2-5% of the general population is chronic user of acid suppressing medication (proton pump inhibitors, H2 receptor antagonists), mostly because of gastro-oesophageal reflux disease (GORD). Prescription data from health insurances show that the number of chronic users increases every year, which has large economic consequences.

There are indications however that on-demand and intermittent therapy can be as effective as daily use. No evidence exists regarding patients who are likely to benefit from intermittent, on-demand therapy or even termination.

In this study several aspects of chronic use of acid suppressive therapy are investigated in family practice patients.

Chronic users are transferred to pantoprazole 20 mg for 4 weeks. Patients with adequate relief of symptoms are randomized in two groups for a period of 13 weeks.

group 1: daily pantoprazole 20 mg, placebo on-demand (indicative for placebo-dependency) group 2: daily placebo, pantoprazole 20 mg on-demand (indicative for pharmacological dependency) Patients visit the research nurse at the beginning of the study and at week 4, 5, 10 and 17.

In this study we are looking for patient characteristics indicative for the dependency on acid suppressive drugs and for possibilities to reduce the dose of these drugs.

Furthermore, aspects described in "secondary outcomes" will be addressed.

Inclusion Criteria:

• male and female (non-pregnant, non-lactating)out-patients between 18-75
• chronic users of acid suppressive therapy for at least 180 days over the last year

Exclusion Criteria:

• stage 3, 4 oesophagitis, Barrett's oesophagus, acute peptic ulcer
• gastric hypersecretory condition, predominantly IBS symptoms, previous gastric/oesophageal surgery, pyloric stenosis
• severe, unstable comorbidities
• alarm symptoms
• malignancies in the past 5 years
• use of NSAID, systemic glucocorticoids, Cox-2 inhibitors, acetylsalicylic acid more than 150 mg daily, drugs with pH-dependent absorption, anticholinergics