I was prescribed this for horrible heartburn and was taking it in the evening, as lying down at night was when the acid bothered me most. In the day it was pretty unpleasant but easier to ignore when busy.
Anyway I happened to read an article about heartburn in general that said take it first thing in the morning on an empty stomache as you get an acid surge when you first eat.
I've been doing this for the last few weeks and have noticed a massive improvement. Acid scarcely bothers me in all day now, which has improved my overall mood, and I still feel the benefits at bedtime.
Anyway might be worth a try and hope this helps someone else.