Do You Have To Take Dulcolax At Night Why Isn't Dulcolax Working?

Why isn't dulcolax working? - do you have to take dulcolax at night

I work 4 tablets of Dulcolax Perles not at 9 clock last night, and yet! My stomach is slightly swollen and hard, but need the bathroom! So I have another at 11 clock in the morning and still nothing! It worked before, does anyone know why not work this time? I do not know how long it usually takes to go to work, but its more than 12 hours! Thank you in advance x