How Long Can Lesuride OD Be Taken For Dyspepsia?

Doctor has diagnosed me as dyspepsia. 1) Dr. Has advised me to take medication( i.e. Lansoprozole for a long time. 2) I am following it and having controll on diet but still I face stomach complication and when I visit doctor he prescribe tablet Lesuride OD 75 and get relief and after two month again I face problem and again visit doctor again Lesuride OD 75 is prescribed. Please let me know how long I have to practice like this.