Acid reflux-zantac

My 3 month old baby has acid reflux problem and we are giving him 1.5 ml zantac(ranitidine) twice everyday for about more than a month. At first it was 1 ml then increased to 1.5. Its working and he is not spiting up much but i am afraid if its safe to give him this medicine everyday for a long period??? When can he stop taking meds and not have acid reflux.. Appretiate any updates