I have started taking omeprazole magnesium recently after my gastroentologist performed an colonoscopy and upper gi, then prescribed it to me. I have had the beginnings of a sore throat for a few days, have felt fatigued, defecating more frequently, starting to hurt when I wipe. I also got tired and had to stop what i was doing, when usually it wouldn t be a problem. I feel a little sick, but not quite like when you know it s coming a few days before.