After baseline investigations, patients will be randomly assigned to either Esomeprazole 20 mg daily or identical looking placebo for 8 weeks. The random allocation sequence will be obtained from a computer-generated list of random numbers in blocks of 10. Concealed allocation is achieved by an independent staff who assigns treatments according to consecutive numbers in sealed envelopes. Study medications are dispensed as sealed packages in consecutive numbers. Medication adherence is measured by pill counts during interval visits.